1.  Peer Reviewed Title: A new estimate of permanent sterility by age: Sterility defined as the inability to conceive. Author: Leridon H Source: Population Studies. 2008 Mar;62(1):15-24. Abstract: The proportion of couples permanently sterile beyond a certain age is an important component of the reproductive process. Unless medical assistance is used, this age is the upper bound of the fecund period. Most estimates of sterility by age of the woman have been derived from natural fertility populations, in which the number of births and the timing of the last birth (of the complete reproductive history) were not controlled by the couples. Because data on these populations do not include pregnancies not ending in a live birth, the sterility estimates apply to the proportion of couples unable to conceive and to have a live birth. For this reason, it is useful to have an estimate of sterility based on the risk of conceiving, independently of the fate of the pregnancy. Using this new estimate, sterility increases with age much more slowly than with most previous estimates. (author's) Language: English Keywords: GLOBAL | RESEARCH REPORT | THEORETICAL MODELS | INFERTILITY | NATURAL FERTILITY | FECUNDABILITY | RISK FACTORS | ESTIMATION TECHNIQUES | Research Methodology | Reproduction | Fertility | Population Dynamics | Demographic Factors | Population | Fecundity | Biology Document Number: 324153 |
| 2. Title: Ratio of boys to girls at birth is not related to the time taken to conceive, or exposure to environmental agents [editorial] Author: Bonde JP; Wilcox A Source: BMJ. British Medical Journal. 2007 Mar 10;334(7592):486-487. Abstract: In 2005, the BMJ published a paper suggesting that subfertile couples were more likely than fertile couples to have boys. This observation was offered as support of the hypothesis that sperm bearing Y chromosomes swim faster through viscous cervical mucous. In the flurry of letters that followed, other researchers reported that their data did not support the sex ratio finding. Furthermore, the sperm swimming hypothesis was exposed as a persistent myth. In this week's BMJ, Joffe and colleagues pool data from several large fecundity studies, further confirming the lack of association between secondary sex ratio (boys to girls at birth) and time to pregnancy. On this point, we are confident the authors are correct. However, their hypothesis that the sex ratio could be a marker of adverse effects on the male reproductive system is less certain. They suggest that a slight decline over time in the secondary sex ratio could represent deterioration in male reproductive health. But does it? (excerpt) Language: English Keywords: GLOBAL | CRITIQUE | EVALUATION | INFANT | PARENTS | SEX RATIO | ENVIRONMENTAL DEGRADATION | TOXICITY | TIME FACTORS | SUBFECUNDITY | FERTILITY DETERMINANTS | Youth | Age Factors | Population Characteristics | Demographic Factors | Population | Family Relationships | Family Characteristics | Family and Household | Sociocultural Factors | Sex Distribution | Sex Factors | Environment | Physiology | Biology | Population Dynamics | Fecundity | Reproduction | Fertility Document Number: 308471 |
| 3. Peer Reviewed Title: Sex ratio and time to pregnancy: analysis of four large European population surveys. Author: Joffe M; Bennett J; Best N; Jensen TK Source: BMJ. British Medical Journal. 2007 Mar 10;334(7592):524-528. Abstract: The objective was to test whether the secondary sex ratio (proportion of male births) is associated with time to pregnancy, a marker of fertility. Design: Analysis of four large population surveys. Setting: Denmark and the United Kingdom. Participants: 49 506 pregnancies. Main outcome measure: Secondary sex ratio. No association was found between the sex ratio and time to pregnancy and no discernible trend was found for sex ratio with time to pregnancy, either within individual datasets or in the pooled analysis. The odds ratios were 0.97 (95% confidence interval 0.90 to 1.04) for contraceptive failures, 1.01 (0.96 to 1.05) for time to pregnancy of 2-4 months, 1.02 (0.97 to 1.08) for 5-10 months, 0.98 (0.93 to 1.03) for 11 months or more, and 0.88 (0.74 to 1.06) for fertility treatment, with 0-1 months as the reference category. No association was found between the secondary sex ratio and time to pregnancy. (author's) Language: English Keywords: DENMARK | UNITED KINGDOM | RESEARCH REPORT | FERTILITY SURVEYS | PREGNANT WOMEN | SEX RATIO | FERTILITY | TIME FACTORS | SUBFECUNDITY | FERTILITY DETERMINANTS | Developed Countries | Europe, Northern | Europe | Europe, Western | Fertility Measurements | Population Dynamics | Demographic Factors | Population | Population Characteristics | Sex Distribution | Sex Factors | Fecundity | Reproduction Document Number: 308472 |
4.  Title: Estimating the fecundability and average conception wait of women among low contraceptive tribal community of southern Ethiopia. Author: Regassa N Source: Studies of Tribes and Tribals. 2007 Dec;5(2):103-111. Abstract: This article is an empirical study aimed at examining the fecundability of women in low contraceptive communities in Southern Ethiopia. The data were collected from 1467 ever-married women who were selected from one of the most populous zones of Southern Ethiopia (the Sidama tribe) through the multistage stratified sampling technique. In order to provide a comparative picture, secondary data collected at national level were used. The study examined the fecundability distribution by age of women using last closed birth interval analysis, and found out that the probability of conception in a month among women of the reproductive age in the study population is about 0.072 with implied average conception wait of 13.88 months. Finally, the study has come up with some policy implications of the findings especially from the viewpoint of fertility decline. (author's) Language: English Keywords: ETHIOPIA | RESEARCH REPORT | QUESTIONNAIRES | EVER MARRIED | WOMEN | AGE DISTRIBUTION | FECUNDABILITY | CONTRACEPTIVE PREVALENCE | EDUCATIONAL STATUS | BIRTH INTERVALS | FERTILITY DECLINE | Developing Countries | Africa, Eastern | Africa, Sub Saharan | Africa | Marital Status | Nuptiality | Demographic Factors | Population | Age Factors | Population Characteristics | Fecundity | Reproduction | Contraceptive Usage | Contraception | Family Planning | Socioeconomic Status | Socioeconomic Factors | Economic Factors | Fertility Measurements | Fertility | Population Dynamics | Fertility Changes Document Number: 323510 |
| 5. Title: A new estimate of permanent sterility by age: Sterility defined as the inability to conceive. Author: Leridon H Source: [Unpublished] 2005. Presented at the 2005 Annual Meeting of the Population Association of America, Philadelphia, Pennsylvania, March 31 - April 2, 2005. 9 p. Abstract: The proportions of couples already and definitely sterile by woman's age have been estimated by various authors. Vincent (1950) gave estimates based on the proportions of newly married couples which remained childless, by age at marriage. Henry (1961) did the same on other samples and derived new estimates based on the comparison of the fertility rate for later fertile couples and the overall fertility rate at a given age. Other authors applied the same methodologies to other populations. These estimates are all based on two main approaches: the first one counts as sterile any couple remaining childless from the time of marriage to the end of the reproductive period; the other one derives the sterility rates from the distribution of age at last live birth. In both cases the data must come from populations where birth control is supposed to be absent or inefficiently used. In this paper, we will first review the previous estimates of sterility, then present the methodology used for our estimation, and finally compare the results with those from previous works. (excerpt) Language: English Keywords: UNITED KINGDOM | CANADA | SUMMARY REPORT | COUPLES | WOMEN | INFERTILITY | FERTILITY RATE | AGE FACTORS | FERTILITY MEASUREMENTS | REPRODUCTIVE BEHAVIOR | SUBFECUNDITY | Developed Countries | Europe, Western | Europe | North America, Northern | Americas | Family Characteristics | Family and Household | Sociocultural Factors | Demographic Factors | Population | Reproduction | Birth Rate | Fertility | Population Dynamics | Population Characteristics | Fecundity Document Number: 319335 |
| 6. Title: Frustrated fertility: infertility and psychological distress among women. Author: McQuillan J; Greil AL; White L; Jacob MC Source: Journal of Marriage and Family. 2003 Nov;65:1007-1018. Abstract: Using a random sample of 580 Midwestern women, we test the hypothesis that women who have experienced infertility report higher psychological distress. Approximately one third of our sample reports having experienced infertility sometime in their lives, although the majority of the infertile now have biological children. Drawing hypotheses from identity and stress theories, we examine whether roles or resources condition the effects of infertility or whether its effects are limited to childless women. Infertility combined with involuntary childlessness (including biological and social) is associated with significantly greater distress. For women in this category, the risk of distress is substantial. (author's) Language: English Keywords: UNITED STATES OF AMERICA | RESEARCH REPORT | SAMPLING STUDIES | THEORETICAL MODELS | WOMEN | INFERTILITY | SUBFECUNDITY | STRESS | DEPRESSION | AGE FACTORS | SOCIOECONOMIC STATUS | FEMALE ROLE | Developed Countries | North America | Americas | Studies | Research Methodology | Demographic Factors | Population | Reproduction | Fecundity | Psychological Factors | Behavior | Mental Disorders | Diseases | Population Characteristics | Socioeconomic Factors | Economic Factors | Social Behavior Document Number: 286224 |
| 7. Title: Estimating time to pregnancy from current durations in a cross-sectional sample. Author: Keiding N; Kvist K; Hartvig H; Tvede M Source: Biostatistics. 2002 Dec;3(4):565-578. Abstract: A new design for estimating the distribution of time to pregnancy is proposed and investigated. The design is based on recording current durations in a cross-sectional sample of women, leading to statistical problems similar to estimating renewal time distributions from backward recurrence times. Non-parametric estimation is studied in some detail and a parametric approach is indicated. The results are illustrated on Monte Carlo simulations and on data from a recent European collaborative study. The role and applicability of this approach is discussed. (author's) Language: English Keywords: DENMARK | RESEARCH REPORT | CROSS SECTIONAL ANALYSIS | RETROSPECTIVE STUDIES | STUDY DESIGN | MATHEMATICAL MODEL | ADULTS | WOMEN | COUPLES | FECUNDABILITY | PREGNANCY | TIME FACTORS | Europe, Northern | Europe | Developed Countries | Research Methodology | Studies | Theoretical Models | Age Factors | Population Characteristics | Demographic Factors | Population | Family Characteristics | Family and Household | Fecundity | Reproduction | Population Dynamics Document Number: 184593 |
| 8. Title: Sub-fecundity and its reproductive health implications: an analysis of change and continuity in parity distribution in Sudan. Author: Otor SC; Pandey A Source: Demography India. 2002;31(1):37-49. Abstract: In this paper, attempt is made to examine the past and current fertility in tile six northern region of Sudan' by studying tile quantum and speed of reproduction. This is in an effort to speculate on tile effect of the changing environmental resource base structure on fecundity in parts of the country in view of the fact that data pertaining to the implications of the biomassbased subsistence economies for female autonomy as well as female reproductive health are not as yet available for most part of sub-Saharan Africa in general and Sudan in particular. Autonomy and reproductive health of women might justifiably be singled out for attention because the ecological changes can be perceived to generate a local environmental resource base structure that does not favour women in view of the fact that women are the main resource producers. We return to this below. Secondly, female reproductive health is important in that women expend more energy on the biological "investment"--i.e., nine months of pregnancy in each child--in children than men do. (excerpt) Language: English Keywords: SUDAN | COMPARATIVE STUDIES | WOMEN | EVER MARRIED | MODERNIZATION | REPRODUCTIVE HEALTH | SUBFECUNDITY | FERTILITY | BEHAVIOR | BIRTH INTERVALS | Africa, Northern | Africa | Developing Countries | Studies | Research Methodology | Demographic Factors | Population | Marital Status | Nuptiality | Social Change | Health | Fecundity | Reproduction | Population Dynamics | Fertility Measurements Document Number: 186492 |
| 9. Title: Some procedures to estimate the level of fecundability of migrant couples based on first birth interval data. Author: Yadava KN; Islam S; Kumar A Source: Demography India. 2002;31(1):65-77. Abstract: In this paper, some procedures to estimate the level of fecundability of migrant couples has been proposed based on the data of the duration of first birth interval treating time to be discrete as well as continuous. A probability mass function (treating time as discrete) and a probability density function (treating time as continuous) have also been proposed for the duration of first birth interval. Appropriate statistical techniques have been used to estimate the parameters involved in tile models. Models are illustrated with some real sets of observed data. (excerpt) Language: English Keywords: BANGLADESH | RESEARCH REPORT | QUESTIONNAIRES | THEORETICAL MODELS | MIGRANT WORKERS | COUPLES | REPRODUCTIVE BEHAVIOR | FECUNDABILITY | MARRIAGE DURATION | FERTILITY | FIRST BIRTH INTERVALS | Asia, Southern | Asia | Developing Countries | Research Methodology | Labor Force | Human Resources | Economic Factors | Family Characteristics | Family and Household | Population Dynamics | Demographic Factors | Population | Fecundity | Reproduction | Marriage | Nuptiality | Birth Intervals | Fertility Measurements Document Number: 186494 |
| 10. Title: Sterility, fecundity: what about the men? Author: de la Rochebrochard E Source: Population and Societies. 2001 Sep;(371):1-4. Abstract: Human reproduction is based on the sexual union of a man and a woman. Nonetheless, scientific research on fertility (births), fecundity (the ability to give birth) or contraception (birth control) is mainly devoted to women and practically ignores men. Some studies on male fecundity have been carried out, however. These focus on the role of men in three aspects of human fecundity: couple infertility, the question of a possible male fecundity decrease with age and the hypothesis that the fecundity of younger male generations may be diminishing. (excerpt) Language: English Keywords: FRANCE | RESEARCH REPORT | EPIDEMIOLOGIC METHODS | CLINICAL RESEARCH | MEN | INFERTILITY | MALE ROLE | AGE FACTORS | SEX FACTORS | SUBFECUNDITY | SPERM COUNT | Developed Countries | Europe, Western | Europe | Research Methodology | Demographic Factors | Population | Reproduction | Social Behavior | Behavior | Population Characteristics | Fecundity | Laboratory Procedures | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Medical Procedures | Medicine | Health Services | Delivery of Health Care | Health Document Number: 312443 |
| 11. Peer Reviewed Title: Return of fertility in nulliparous women after discontinuation of the intrauterine device: comparison with women discontinuing other methods of contraception. Author: Doll H; Vessey M; Painter R Source: British Journal of Obstetrics and Gynaecology. 2001 Mar;108:304-14. Abstract: The aim was to clarify the effect of using the IUD on fertility in nulliparous women. A prospective cohort study of two groups of nulliparous women, one recruited while using an IUD and the other while using an oral contraceptive (OC), was conducted. 17 family planning clinics in England and Scotland were covered by the study. 1071 nulliparous, married women, aged 18-40 years, 558 of whom contributed information to the main objective of the study, made up the study sample. The women were recruited between 1982 and 1985 and followed up annually to 1994. Dates and reasons for any contraceptive method changes (which were most frequently to barrier methods) were recorded, together with the outcome of any pregnancies, at each follow up. The main outcome measure was the number of nulliparous women giving birth at term after stopping contraception (OC, IUD or barrier method) in order to conceive. Women who stopped using a barrier method to achieve a planned pregnancy conceived most quickly: 54% were delivered after 1 year vs. 39% of IUD and 32% of OC users (log rank P = 0.002). There was no association between fertility and duration of OC use. However, short-term IUD users (<42 months) showed a fertility pattern more favorable than seen in those discontinuing OCs, with increasing duration of IUD use being associated with decreasing fertility (linear trend P = 0.005); the fertility of women who had used the IUD for 78+ months was the most impaired (28% were delivered by 12 months vs. 46% of short-term users; at 36 months the corresponding figures were 79% vs. 91%). This association remained after adjusting for potential confounding factors, including maternal age, husband's social class, and history of gynecological illnesses, factors which themselves had independent associations with fertility. (author's) Language: English Keywords: UNITED KINGDOM | SCOTLAND | RESEARCH REPORT | PROSPECTIVE STUDIES | COHORT ANALYSIS | WOMEN | FECUNDABILITY | NULLIPARITY | CONTRACEPTION TERMINATION | IUD | United Kingdom | Europe, Western | Europe | Developed Countries | Studies | Research Methodology | Demographic Factors | Population | Fecundity | Reproduction | Parity | Fertility Measurements | Fertility | Population Dynamics | Contraception | Family Planning | Contraceptive Methods Document Number: 160078 |
| 12. Peer Reviewed Title: The relationship between cervical secretions and the daily probabilities of pregnancy: effectiveness of the TwoDay Algorithm. Author: Dunson DB; Sinai I; Colombo B Source: Human Reproduction. 2001 Nov;16(11):2278-2782. Abstract: BACKGROUND: The TwoDay Algorithm is a simple method for identifying the fertile window. It classifies a day as fertile if cervical secretions are present on that day or were present on the day before. This approach may be an effective alternative to the ovulation and symptothermal methods for populations and programmes that find current natural family planning methods difficult to implement. METHODS: We used data on secretions from a large multinational European fecundability study to assess the relationship between the days predicted to be potentially fertile by the TwoDay Algorithm and the day-specific probabilities of pregnancy based on intercourse patterns in 434 conception cycles from the study. RESULTS: The days around ovulation that had the highest fecundability were the days most likely to be classified as fertile by the TwoDay Algorithm. In addition, intercourse on a particular day in the fertile interval was twice as likely to result in a pregnancy if cervical secretions were present on that day or the day before. CONCLUSIONS: The TwoDay Algorithm is effective, both in identifying the fertile days of the cycle and in predicting days within the fertile interval that have a high pregnancy rate. Our data provide the first direct evidence that cervical secretions are associated with higher fecundability within the fertile window. (author's) Language: English Keywords: EUROPE | RESEARCH REPORT | STUDIES | PROBABILITY | FERTILITY | WOMEN | FECUNDABILITY | CERVICAL MUCUS | NATURAL FAMILY PLANNING | Developed Countries | Research Methodology | Statistical Studies | Population Dynamics | Demographic Factors | Population | Fecundity | Reproduction | Cervix | Uterus | Genitalia, Female | Genitalia | Urogenital System | Physiology | Biology | Family Planning, Behavioral Methods | Family Planning Document Number: 174884 |
| 13. Title: [Fetal mortality and abortion] Mortalidad fetal y aborto. Author: Hernández D Source: In: La población de México: tendencias y perspectivas sociodemográficas hacia el siglo XXI, edited by José Gómez de León Cruces and Cecilia Rabell Romero. Mexico City, Mexico, Consejo Nacional de Población [CONAPO], 2001. :349-362. Abstract: Demographic phenomena are affected by diverse factors. In the case of fertility, guidelines for studiying the phenomenon have been developed based on the concept that the socioeconomic, cultural, and biological elements that influence it operate through some closely related factors. Davis and Blake proposed 11 of these factors, also known as intermediate variables of fecundity (1956), which can be organized into three categories: (i) factors that affect exposure to intercourse; (ii) factors that affect the risk of conceiving, and (iii) factors that affect gestation. Within the latter two, one finds fetal mortality for involuntary or voluntary causes, such as spontaneous or induced abortion. Nevertheless, the analysis of fetal mortality is limited for diverse reasons. Perhaps the most debated issue is related to the judicial condition of induced abortions. In Mexico, abortions are considered crimes except in determined circumstances, a fact that is connected with an underreporting of this type of event (Tolbert, Ehrenfeld, and Lamas, 1996; Salas, 1996) (excerpt) Spanish Abstract: Los fenómenos demográficos se ven afectados por diversos factores. En el caso de la fecundidad, para su estudio se han desarrollado esquemas basados en el concepto de que los elementos socioeconómicos, culturales y biológicos que influyen en ella operan mediante unos cuantos factores próximos. Davis y Blake propusieron 11 de estos factores, también conocidos como variables intermedias de la fecundidad (1956), que pueden agruparse en tres categorías: i) factores que afectan la exposición al coito; ii) factores que afectan el riesgo de concebir; y iii) factores que afectan la gestación. Dentro de estos últimos se encuentra la mortalidad fetal por causas involuntarias o voluntarias, a saber: el aborto espontáneo o el inducido. Sin embargo, el análisis de la mortalidad fetal se ve limitado por diversos motivos, Quizá el que ha sido más discutido se relaciona con la condición jurídica de los abortos inducidos, que en México sólo en determinadas circunstancias no son clasificados como delito, lo que se vincula con una subdeclaración de este tipo de hechos (Tolbert, Ehrenfeld y Lamas, 1996; Salas, 1996). (extracto) Language: Spanish Keywords: MEXICO | FETAL DEATH | INFANT MORTALITY | ABORTION | FECUNDABILITY | SOCIOECONOMIC FACTORS | North America | Latin America | Americas | Developing Countries | Mortality | Population Dynamics | Demographic Factors | Population | Fertility Control, Postconception | Family Planning | Fecundity | Reproduction | Economic Factors Document Number: 179726 Notification |
| 14. Peer Reviewed Title: Regional differences in waiting time to pregnancy among fertile couples from four European cities. Author: Jensen TK; Slama R; Ducot B; Suominen J; Cawood EH; Andersen AG; Eustache F; Irvine S; Auger S; Jouannet P; Vierula M; Jørgensen N; Toppari J; Skakkebaek NE; Keiding N; Spira A Source: Human Reproduction. 2001 Dec;16(12):2697-2704. Abstract: BACKGROUND: A previous European study found a longer time to pregnancy (TTP) among fertile women from Paris compared with women from other Western European countries. A co-ordinated, cross-sectional study of pregnant couples from Denmark (Copenhagen), France (Paris), Scotland (Edinburgh) and Finland (Turku) was therefore undertaken to assess differences in waiting TTP among couples from these cities. METHODS: Pregnant women were invited to participate when they showed up for their first antenatal visit in one of the four centres. Inclusion criteria included that their partner was 20-45 years of age and born in the country in which he was currently living and that the pregnancy was achieved without fertility treatment. Both partners filled in a questionnaire and the man underwent a physical examination and delivered a semen sample (Turku: n = 237. Copenhagen: n = 302. Edinburgh: n= 212. Paris: n = 191). RESULTS: French couples had a decreased probability of conception compared with couples from the other three countries, although only after adjustment for confounders. No significant differences between couples from the three other countries were found. CONCLUSION: The observed geographical differences in TTP remain unexplained and were not due to differences in semen quality, but may be caused by varying exposures to an environmental factors or psychological distress. In addition, selection bias due to the low participation rates cannot be ruled out. Future studies examining the causes of geographical differences in TTP are needed. (author's) Language: English Keywords: DENMARK | FINLAND | FRANCE | SCOTLAND | RESEARCH REPORT | CROSS SECTIONAL ANALYSIS | QUESTIONNAIRE DESIGN | MEASUREMENT | PREGNANT WOMEN | FERTILITY | GEOGRAPHIC FACTORS | TIME FACTORS | FECUNDABILITY | SEMEN | ENVIRONMENTAL IMPACT | ANALYSIS | Europe, Northern | Europe | Developed Countries | Europe, Western | United Kingdom | Research Methodology | Survey Methodology | Surveys | Sampling Studies | Studies | Population Characteristics | Demographic Factors | Population | Population Dynamics | Fecundity | Reproduction | Seminal Vesicles | Genitalia, Male | Genitalia | Urogenital System | Physiology | Biology | Environment Document Number: 174883 |
| 15. Title: Seasonality and fertility in rural Mali: the role of socioeconomic resources] Saisonnalite et fecondite dans le Mali rural: le role des ressources socio-economiques. Author: Masudi Uchudi J Source: In: Regulations demographiques et environnement. Actes des VIes Journees demographiques de l'ORSTOM, 22-24 septembre 1997 - Paris, sous la direction de Laurent Auclair, Patrick Gubry, Michel Picouet, Frederic Sandron. Paris, France, Institut de Recherche pour le Developpement, 2001 Feb. :93-102. (Etudes du CEPED No. 18) Abstract: Almost all human populations have seasonal variations in birth rates due to a range of different biological and behavioral factors. The rainy season is the most difficult of seasons in most tropical areas. The beginning of the humid season marks the beginning of a difficult period of the year during which food supplies are short, agricultural chores take great physical effort, diseases abound, and child care, family hygiene, and cooking are neglected by already overburdened women. The author explores whether seasonality is linked with a decline in pregnancy from the beginning of the rainy season and if women of relatively higher income households are more likely to conceive during that period. Most rural populations of the Western Sahel experience seasonal difficulties of varying acuteness depending upon the severity of climatic changes and the ability to cope with prevailing agro-climatic conditions given the available technological and socioeconomic resources. Therefore during the season before harvest, food supplies dwindle while the labor demand is highest. People are also at elevated risk of disease during the rainy season. Data used in this study were drawn from the Demographic and Health Survey conducted during March-August 1987 by the Sahel Institute. Analysis of the data indicates that in Mali's rural population, higher household economic status is associated with a greater likelihood of conception at the beginning of the rainy season. The phenomenon results from the increase in supplies and/or income at that time. French Abstract: Presque toutes les populations humaines se caractérisent par des variations saisonnières de la natalité, des variations qui résultent de nombreux facteurs biologiques et comportementaux. Dans la plupart des zones tropicales, la saison la plus difficile est celle des pluies. Le début de la saison humide correspond à une période de l'année très défavorable durant laquelle il manque de denrées alimentaires, les tâches agricoles exigent beaucoup d'énergie physique, les maladies prévalent, et les soins aux enfants, l'hygiène familiale, et la cuisine sont négligés par les femmes autrement occupées par leur travail. L'auteur essaye de déterminer si la saisonnalité est liée à un creux saisonnier dans la conception au début de la saison des pluies et si la probabilité pour une femme de concevoir au début de la saison des pluies augmente avec le revenu du ménage. La plupart des populations rurales du Sahel occidental souffrent des difficultés saisonnières dont l'acuité dépend tous les deux de la sévérité des variations climatiques et du niveau des ressources technologiques et socio-économiques dans lesquelles s'inscrivent les conditions agro-climatiques. C'est ainsi que durant la saison précédant les moissons, la nourriture se raréfie alors que la demande de main-d'oeuvre est la plus élevée. La saison des pluies correspond aussi à une élévation des risques de maladie. Les données utilisées dans cette étude proviennent de l'Enquête démographique et de santé effectuée entre mars et août 1987 par l'Institut du Sahel. Les résultats de l'analyse des données indiquent que dans les campagnes maliennes, l'amélioration du statut économique du ménage est liée à une plus forte probabilité de concevoir au début de la saison des pluies. Ce phénomène résulte de l'augmentation des stocks et/ou des revenus à cette saison. Language: French Keywords: MALI | RESEARCH REPORT | RURAL POPULATION | SEASONAL VARIATION | REPRODUCTIVE BEHAVIOR | FECUNDABILITY | FERTILITY DETERMINANTS | SOCIOECONOMIC FACTORS | INCOME | FOOD SUPPLY | HOUSEHOLDS | Developing Countries | Africa, Western | Africa, Sub Saharan | Africa | Population Characteristics | Demographic Factors | Population | Population Dynamics | Fertility | Fecundity | Reproduction | Economic Factors | Natural Resources | Environment | Family and Household Document Number: 158130 |
| 16. Peer Reviewed Title: Time to pregnancy as a correlate of fecundity: differential persistence in trying to become pregnant as a source of bias. Author: Basso O; Juul S; Olsen J Source: International Journal of Epidemiology. 2000 Oct;29(5):856-61. Abstract: Subfecundity is a frequent and often serious problem and it is important to identify its preventable determinants and to monitor fecundity over time. Since follow-up studies are difficult and expensive to conduct, time to pregnancy (TTP) in pregnant women is often used as a surrogate measure of fecundity. TTP data can be retrieved at low costs and they need no valid population registry as a source for sampling. While TTP may serve as a valid surrogate measure in many situations, its validity rests upon a number of assumptions. The authors have analyzed one of these overlooked assumptions, the importance of persistence in trying to become pregnant. By means of computer simulations, the authors estimated bias caused by differences in persistence in pregnancy attempts. The authors investigated whether the assumptions made in the simulation were realistic by using empirical data from a European study. The mean waiting time to pregnancy and other estimates of subfecundity (or infertility) strongly depend upon the persistence of couples in pursuing a pregnancy. The authors show that even moderate changes in the planning behavior considerably modify the waiting time distribution. Empirical data confirm that persistence in trying to become pregnant is age-related. Persistence in pregnancy attempts affects outcome measures of subfecundity in studies based upon TTP in pregnant women. It is likely that the length of time during which couples keep trying to become pregnant is influenced by a number of factors which would probably change over time or be different between populations to be compared. (author's) Language: English Keywords: EUROPE | RESEARCH REPORT | THEORETICAL MODELS | SUBFECUNDITY | PREGNANCY OUTCOMES | EPIDEMIOLOGY | Developed Countries | Research Methodology | Fecundity | Reproduction | Pregnancy | Public Health | Health Document Number: 153040 |
| 17. Peer Reviewed Title: Daily fecundability: first results from a new data base. Author: Colombo B; Masarotto G Source: DEMOGRAPHIC RESEARCH. 2000 Sep 6;3:[39] p.. Abstract: This multicenter study has produced a database of 7017 menstrual cycles contributed by 881 women. It provides improved knowledge on length and location of the "fertile window" (identified as of up to 12 days duration) and the patterns and level of daily conception probability. The day of ovulation was identified in each cycle from records of basal body temperature and mucus symptoms. By referencing days of intercourse to the surrogate ovulation markers, estimates of daily fecundability were computed either directly or by the Scwartz model, both for single and multiple acts of intercourse in the fertile window. The relationship between coital pattern and fecundability has been explored. Univariate analysis underlines the significant link with fecundability only of the woman's reproductive history. (author's) Language: English Keywords: EUROPE | RESEARCH REPORT | FECUNDABILITY | MENSTRUAL CYCLE | FERTILE PERIOD | BASAL BODY TEMPERATURE METHOD | CERVICAL MUCUS METHOD | Developed Countries | Fecundity | Reproduction | Menstruation | Natural Family Planning | Family Planning, Behavioral Methods | Family Planning Document Number: 152360 |
| 18. Title: Declining human fertility? [editorial] [Assiste-t-on au déclin de la fertilité humaine ?] [éditorial] Author: Jensen TK; Keiding N; Scheike T; Slama R; Spira A Source: FERTILITY AND STERILITY.. 2000 Feb;73(2):421-2. Abstract: This article comments on the conclusion reached by Akre et al. in their study on human fertility. Akre et al. concluded that subfertility (measured as a waiting time to pregnancy of >1 year) decreased from 1983 to 1993 in Sweden and that the decline followed a birth cohort pattern. In addition, they speculated that the decrease in subfertility during the 1980s is mainly due to the eradication of gonorrhea. However, the data they presented does not seem to justify their conclusion. The researchers did not study the consequences of truncation of the waiting-time distribution in 1993 and 1983, the association between smoking and infertility, and declining semen quality in order to further support their conclusion. French Abstract: Cet article commente la conclusion à laquelle sont arrivés Akre et al. dans leur étude sur la fertilité humaine. Akre et al. conclurent que la sous-fertilité (mesurée en tant que temps d'attente de la grossesse supérieur à 1 année) a diminué de 1983 à 1993 en Suède et que le déclin a suivi un modèle de cohorte de naissance. De plus, ils ont spéculé que la baisse de la sous-fertilité durant les années 80 est principalement due à l'éradication de la gonorrhée. Cependant, les données qu'ils ont présentées ne paraissent pas justifier leur conclusion. Les chercheurs n'ont pas étudié les conséquences de troncature de la distribution du temps d'attente en 1993 et 1983, l'association entre le tabagisme et la stérilité et la qualité décroissante du sperme pour mieux étayer leur conclusion. Language: English Keywords: SWEDEN | CRITIQUE | FERTILITY DECLINE | SUBFECUNDITY | FERTILITY | Developed Countries | Europe, Northern | Europe | Fertility Changes | Population Dynamics | Demographic Factors | Population | Fecundity | Reproduction Document Number: 148034 |
| 19. Title: Impaired fertility in HIV-1-infected pregnant women: a clinic-based survey in Abidjan, Cote d'Ivoire, 1997. Author: Desgrees du Lou A; Msellati P; Yao A; Noba V; Viho I; Ramon R; Welffens-Ekra C; Dabis F Source: AIDS. 1999;13(4):517-21. Abstract: The reproductive histories of 1201 consecutive women attending a prenatal clinic in Abidjan, Ivory Coast, in 1997 were investigated to determine whether HIV-infected women become pregnant less often than HIV-negative women. This issue is important because, if HIV-positive women have fewer pregnancies or more miscarriages than other women, then women who visit antenatal clinics are not representative of all women of childbearing age and HIV prevalence is underestimated at these centers. All women were unaware of their HIV status at study entry. 169 women (14.3%) were HIV-positive, but it was not possible to determine whether the pregnancies occurred before or after infection. The mean age at first coitus was 16 years among HIV-positive and 17 years among HIV-negative women. The mean number of pregnancies was higher among HIV-positive women under 20 years of age than HIV-negative women of this age (2.1 vs. 1.7), but this trend was reversed from age 25 years onward (4.2 vs. 4.7). The interval between the last two pregnancies was longer among HIV-infected women than uninfected women (36.4 vs. 33 months). The gap was greatest among women 25-29 years of age (51.8 vs. 35.7 months). In multivariate analysis, after adjustment for age, last pregnancy outcome, duration of postpartum amenorrhea, use of contraceptives during this interval, marital status, and educational level, HIV infection significantly delayed the occurrence of the current pregnancy (Cox model hazard ratio, 0.83; 95% confidence interval, 0.69-0.99). Since HIV infection appears to compromise physiologic ability to become pregnant, HIV prevalence assessed at antenatal centers should be adjusted for the fertility differences between HIV-positive and HIV-negative women. Language: English Keywords: COTE D'IVOIRE | RESEARCH REPORT | COMPARATIVE STUDIES | HIV INFECTIONS | WOMEN | AIDS | PREGNANT WOMEN | PREGNANCY | SUBFECUNDITY | ANTENATAL CARE | EPIDEMIOLOGIC METHODS | Developing Countries | Africa, Western | Africa, Sub Saharan | Africa | Studies | Research Methodology | Viral Diseases | Diseases | Demographic Factors | Population | Population Characteristics | Reproduction | Fecundity | Maternal Health Services | Maternal-Child Health Services | Primary Health Care | Health Services | Delivery of Health Care | Health Document Number: 141556 |
| 20. Title: Age-dependent decline of female fecundity is caused by early foetal loss. Author: Holman DJ; Wood JW; Campbell KL Source: Seattle, Washington, University of Washington, Seattle Population Research Center, [1999] 9 p. (Seattle Population Research Center Working Paper No. 00-03) Abstract: This study estimated the fecundability and fetal loss model by collecting data from a near-natural fertility population in rural Bangladesh and using a highly sensitive and specific assay to detect pregnancies at early gestational ages. The results showed that maternal age significantly affected both fecundability and fetal loss simultaneously. The probability of pregnancy loss steadily increases with maternal age, and age-related increase in risk of fetal loss closely parallels the increasing proportion of abnormal conceptuses by maternal age. Total fecundability was remarkably constant across most of the reproductive lifespan. Fecundability was at a maximum of 1 at age 20 and declined very slowly until the late 30s, when it declined rapidly and reached zero by age 48. Overall, the results suggest that the observed age-related decline in apparent fecundability (the monthly or cycle-wise probability of conception given that the pregnancy survives long enough to be detected using some particular method) over most of the reproductive span is not caused by an age-related decline in total fecundability (refers to the probability that fertilization occurs in a single month or cycle for a sexually active woman). Rather, it results from an age-related increase in early fetal loss that is masked by the inability to detect early pregnancies. Language: English Keywords: BANGLADESH | THEORETICAL STUDIES | THEORETICAL MODELS | RURAL POPULATION | WOMEN | FETAL DEATH | FECUNDABILITY | AGE FACTORS | Asia, Southern | Asia | Developing Countries | Research Methodology | Population Characteristics | Demographic Factors | Population | Mortality | Population Dynamics | Fecundity | Reproduction Document Number: 149434 |
| 21. Title: Infertility and subfecundity in population-based samples from Denmark, Germany, Italy, Poland and Spain. Author: Karmaus W; Juul S Source: EUROPEAN JOURNAL OF PUBLIC HEALTH. 1999 Sep;9(3):229-35. Abstract: No uniform data that give basic information on the societal burden of infertility and subfecundity exists in Europe. In a population-based survey the prevalence of subfecundity was ascertained by means of a standardized interview with women in Denmark, Germany, Poland, Italy, and Spain. The time of unprotected intercourse (TUI), either leading or not leading to pregnancy, was applied as a uniform measure of fecundity. Population-based samples of women 25-44 years of age were recruited. Altogether, 6630 women participated in the study. With regard to the first pregnancy, 19% of all couples had a TUI of more than 12 months, which is within the range of most previous findings. Regarding the most recent and first TUI in individual lives, if it had occurred within the previous 5 years, 23.4% overall did not conceive within 12 months (in Poland, 33.3%; in northern Italy and Germany, 26.2%; in Denmark, 23.3%; in Spain, 18.6%; in southern Italy, 14.8%). Secondary subfecundity was more prevalent in Poland. When stratifying for planning of a pregnancy, the differences between countries diminished, particularly for the most recent TUI. However, the pattern of a higher prevalence of subfecundity in Poland, northern Italy, Denmark, and Germany and a lower prevalence (<20%) in Spain and southern Italy remains. Important differences in the prevalence of subfecundity exist between the six European regions investigated. Comparisons should first consider TUI or planned TUI to reduce the impact of distorting factors, which are mainly due to differing cultures of family planning in Europe. (author's) Language: English Keywords: EUROPE | RESEARCH REPORT | SURVEYS | PREVALENCE | PREGNANCY, PLANNED | INFERTILITY | SUBFECUNDITY | Developed Countries | Sampling Studies | Studies | Research Methodology | Measurement | Reproductive Behavior | Fertility | Population Dynamics | Demographic Factors | Population | Reproduction | Fecundity Document Number: 151875 |
| 22. Peer Reviewed Title: Reduced fertility associated with HIV: the contribution of pre-existing subfertility. Author: Ross A; Morgan D; Lubega R; Carpenter LM; Mayanja B Source: AIDS. 1999;13(15):2133-41. Abstract: HIV-1 infection is associated with lower fertility among women in sub-Saharan Africa and this association is not explained by the frequency of sexual intercourse, illness, knowledge of HIV status of infection with other sexually transmitted diseases. Women with fertility problems are at increased risk of marital instability and, therefore, HIV infection; consequently, pre-existing subfertility among HIV-infected women may contribute to the association. This study examines the relationship between HIV-1 infection and the incidence of recognized pregnancy and the role of low gravidity prior to seroconversion in rural Uganda. A group of 176 women (80 HIV infected and 96 uninfected) were enrolled into an HIV-1 natural history cohort and invited to attend 3- monthly clinic appointments. Data from clinic visits were analyzed to assess the independent effects of HIV infection and age, lactation, illness, reported frequency of sexual intercourse and sexually transmitted diseases (STD) on the risk of pregnancy in the following 3 months. The number of previous pregnancies was recorded at enrolment, and the effect of gravidity was examined for the subgroup of women who were uninfected at enrolment or who enrolled within 2 years of their estimated seroconversion date. During follow-up, 124 pregnancies were observed in 83 women beginning in the 3 months following 47 (7.0%) of 669 visits made by HIV-infected women and 77 (9.5%) of 812 visits by HIV-negative women (P = 0.12). Adjusting for age, lactation, illness, STD and the reported frequency of sexual intercourse, the estimated reduction in the risk of pregnancy associated with HIV infection was 47% [95% confidence interval (CI) 18-66]. Pre-existing low gravidity was strongly associated with a reduced incidence of pregnancy (odds ratio 0.39; CI 0.19-0.81). Additionally, adjusting for low gravidity reduced the estimate of the effect of HIV infection by almost a half, to 25% (95% CI-57-29). Low gravidity prior to seroconversion accounts for almost 50% of the observed association between HIV infection and lowered incidence of pregnancy, after adjusting for age, lactation, illness, STD and the frequency of sexual intercourse. (author's) Language: English Keywords: UGANDA | RESEARCH REPORT | COHORT ANALYSIS | RURAL POPULATION | WOMEN | FERTILITY | SUBFECUNDITY | HIV INFECTIONS | Developing Countries | Africa, Eastern | Africa, Sub Saharan | Africa | Research Methodology | Population Characteristics | Demographic Factors | Population | Population Dynamics | Fecundity | Reproduction | Viral Diseases | Diseases Document Number: 162514 |
| 23. Title: Reproductive change in Zimbabwe and Kenya: the role of the proximate determinants in recent fertility trends. Author: Sibanda A Source: SOCIAL BIOLOGY.. 1999 Spring-Summer;46(1-2):82-99. Abstract: This study assesses and compares changes in the relative importance of the four proximate determinants of fertility, namely, marriage patterns, contraceptive use, postpartum infecundability, and primary sterility, between two sets of Demographic Health Surveys (DHS) conducted in Zimbabwe and Kenya. Data were drawn from the 1988-89 and 1994 Zimbabwe DHS and the 1988 and 1993 Kenya DHS. The results show that the fertility-inhibiting effects of contraception are more important than the effects of postpartum infecundability, marriage patterns, or sterility in Zimbabwe. Furthermore, the contraceptive patterns have their greatest fertility-suppressing effects in the middle and younger age groups. In Kenya, on the other hand, the dominant fertility-inhibiting effect is postpartum infecundability, with contraception coming in second. Another important finding is the fairly marked extent to which observed levels of fertility in Kenya and Zimbabwe can be attributed to concomitant variations in postpartum lactational infecundability, contraception, and nuptiality. Language: English Keywords: KENYA | ZIMBABWE | RESEARCH REPORT | DEMOGRAPHIC AND HEALTH SURVEYS | FERTILITY DETERMINANTS | FERTILITY | MARRIAGE PATTERNS | CONTRACEPTIVE USAGE | INFERTILITY | FECUNDABILITY | Developing Countries | Africa, Eastern | Africa, Sub Saharan | Africa | Africa, Southern | Demographic Surveys | Population Dynamics | Demographic Factors | Population | Marriage | Nuptiality | Contraception | Family Planning | Reproduction | Fecundity Document Number: 147706 |
| 24. Title: Smoking and your reproductive health. Source: Contraception Report. 1998 Jul;9(3):[3] p.. Abstract: Not everyone realizes, however, that smoking is also harmful to a woman's reproductive health. For example, smoking is associated with cervical cancer. Among women over age 35 years who are trying to prevent pregnancy, smoking can cause higher risks of side effects with oral contraceptives (the birth control pill). For women trying to get pregnant, cigarette smoking can cause a delay in how long it takes to become pregnant. And, once a woman gets pregnant, smoking can harm the woman and her fetus. The cervix is the opening of the uterus (womb) into the vagina. Women who smoke are more likely to develop cervical cancer than those who don't. The reason for this relationship is not known; however, some studies have found a chemical byproduct of nicotine (the addictive drug in cigarettes) in the secretions of the cervix. The poisons in cigarette smoke may also get to the cervix through the bloodstream. (excerpt) Language: English Keywords: UNITED STATES OF AMERICA | RECOMMENDATIONS | EPIDEMIOLOGIC METHODS | WOMEN | TOBACCO USE | REPRODUCTIVE HEALTH | CERVICAL CANCER | RISK ASSESSMENT | ORAL CONTRACEPTIVES, SIDE EFFECTS | PREGNANCY, ECTOPIC | LOW BIRTH WEIGHT | SUBFECUNDITY | North America | Americas | Developed Countries | Research Methodology | Demographic Factors | Population | Behavior | Health | Cancer | Neoplasms | Diseases | Evaluation | Contraceptive Safety | Safety | Public Health | Pregnancy Complications | Birth Weight | Body Weight | Physiology | Biology | Fecundity | Reproduction Document Number: 312865 |
| 25. Title: Interpreting the beta geometric in comparative fecundability studies. Author: Crouchley R; Dassios A Source: BIOMETRICS. 1998 Mar;54(1):161-7. Abstract: Fecundability is usually measured by the number of menstrual cycles required for a sexually active, noncontracepting female to become pregnant. However, many observed and unobserved factors can affect human fecundability. The beta distribution has often been used to describe variation in fecundability between couples when modeling the number of menstrual cycles required for a couple to achieve pregnancy. Groups are often compared for a condition or factor which could affect conception rates. However, when heterogeneity is present in each group, comparing group-specific parameters is not very informative with regard to what any differences may imply for individual couples. The authors present a quantile ratio which provides an individual-level interpretation of any between-group differences in the beta distribution, with results illustrated on the 2 examples of Ridout and Morgan. Language: English Keywords: THEORETICAL STUDIES | MATHEMATICAL MODEL | FECUNDABILITY | Theoretical Models | Research Methodology | Fecundity | Reproduction Document Number: 141901 |
| 26. Title: Survey of subfertility patients attending a community clinic over a two year span, before and after national folate campaigns. Author: Elliman A Source: British Journal of Family Planning. 1998 Jul;24(2):80-1. Abstract: Findings are presented from a retrospective survey of two cohorts of new patients seeking subfertility advice who presented to the subfertility and preconception service of the Croydon Community Health Trust. The first cohort of 40 women presented between April 1, 1995, and March 31, 1996, and the second cohort of 36 women presented between April 1, 1996, and March 31, 1997. The national folate supplementation campaign was conducted in March-April 1996, during which local activities were held to increase awareness among health professionals. The women in cohorts 1 and 2 were aged 21-42 and 19-43 years, respectively, and had been attempting to become pregnant for 2-96 months. 45% of women in the first cohort and 36% in the second cohort had never been pregnant, while 12.5% and 27% of women in the two cohorts, respectively, had a prior history of pregnancy termination. A low incidence was observed at the clinic of correct usage of folate at the time of first attendance throughout the entire period and although folate supplementation had been discussed with some of the women upon their referral to Croydon, 100% uptake of such supplementation had not been achieved. Family planning patients at community services in Croydon should be offered routine rubella testing within 1 year of first attendance if they have not previously given birth in the UK since 1980. Furthermore, couples who are attempting to conceive must be urged to stop smoking preconceptually. Language: English Keywords: UNITED KINGDOM | RESEARCH REPORT | SUBFECUNDITY | CLIENTS | SERUM FOLATE LEVEL | FOOD SUPPLEMENTATION | TOBACCO USE | RUBELLA | COUNSELING | NEEDS | Developed Countries | Europe, Western | Europe | Fecundity | Reproduction | Program Activities | Programs | Organization and Administration | Hemic System | Physiology | Biology | Nutrition Programs | Primary Health Care | Health Services | Delivery of Health Care | Health | Behavior | Viral Diseases | Diseases | Clinic Activities | Economic Factors Document Number: 135612 |
| 27. Title: Adult and prenatal exposures to tobacco smoke as risk indicators of fertility among 430 Danish couples. Author: Jensen TK; Henriksen TB; Hjollund NH; Scheike T; Kolstad H; Giwercman A; Ernst E; Bonde JP; Skakkebaek NE; Olsen J Source: AMERICAN JOURNAL OF EPIDEMIOLOGY. 1998 Nov 15;148(10):992-7. Abstract: The effect of male and female current smoking and smoking exposure in utero on fecundability was investigated in a prospective cohort study conducted in 1992-95 in Aarhus and Copenhagen, Denmark. From a nationwide mailing to 52,255 trade union members who were 20-35 years old, lived with a partner, and had no children, a total of 430 couples were recruited. Couples discontinued contraception at study enrollment and were followed for 6 menstrual cycles or until pregnancy. A logistic regression model was used with pregnancy outcome of each cycle in a Cox discrete model calculating the fecundability odds ratio. 127 women (30%) and 137 men (32%) were smokers at study enrollment; 163 women (42%) and 154 men (40%) reported exposure to cigarette smoke in utero. In the 6 cycles of follow-up, 51.2% of smokers and 63.0% of nonsmokers conceived. After adjustment for female body mass index and alcohol intake, female reproductive organ diseases, semen quality, and duration of the menstrual cycle, the fecundability odds ratio (OR) for smoking women exposed in utero was 0.53 (95% confidence interval (CI), 0.31-0.91) compared with unexposed smokers. The fecundability OR for nonsmoking women exposed in utero was 0.70 (95% CI, 0.48-1.03) and that for female smokers not exposed in utero was 0.67 (95% CI, 0.42-1.06). In utero exposure was also associated with a decreased fecundability OR in men (0.68; 95% CI, 0.48-0.97), but current smoking did not reduce fecundability significantly. These findings indicate cigarette smoking is a reproductive health hazard both before and during pregnancy. Language: English Keywords: DENMARK | RESEARCH REPORT | PROSPECTIVE STUDIES | FECUNDABILITY | RISK FACTORS | TOBACCO USE | Europe, Northern | Europe | Developed Countries | Studies | Research Methodology | Fecundity | Reproduction | Biology | Behavior Document Number: 138070 |
| 28. Title: Caffeine intake and fecundability: a follow-up study among 430 Danish couples planning their first pregnancy. Author: Jensen TK; Henriksen TB; Hjollund NH; Scheike T; Kolstad H; Giwercman A; Ernst E; Bonde JP; Skakkebaek NE; Olsen J Source: REPRODUCTIVE TOXICOLOGY. 1998 May-Jun;12(3):289-95. Abstract: The independent and combined effects of smoking and caffeine intake from different sources on fecundability were assessed in a national survey of 423 Danish couples. Couples were recruited to the study in 1992-95 through a mailing to 52,255 female trade union members seeking women who were 20-35 years old, lived with a partner, had no previous pregnancies, and intended to discontinue contraception in order to become pregnant. A total of 1596 cycles were included in the 6-month study and the cycle-specific association between caffeine intake and fecundability was analyzed in a logistic regression model with the outcome (pregnant, not pregnant) in a Cox discrete model. Compared with nonsmoking women with a caffeine intake less than 300 mg/day, nonsmoking women who consumed 300-700 mg/day of caffeine had a fecundability odds ratio (FR) of 0.88 (95% confidence interval (CI), 0.60-1.31), while those with a higher consumption had an FR of 0.63 (95% CI, 0.25-1.60), after adjustments for body mass index, alcohol intake, diseases of the female reproductive organs, semen quality, and duration of the menstrual cycle. No such dose-response relationship was detected among smokers. The same decline in point estimates of the FR was present was males. Smoking women whose only source of caffeine was coffee (over 300 mg/day) had a reduced FR (0.34; 95% CI, 0.12-0.98). The lack of adverse effect among smokers may be due to faster metabolism and clearance of caffeine. Overall, these findings indicate that nonsmoking women who wish to achieve pregnancy should consider reducing their caffeine intake. Language: English Keywords: DENMARK | RESEARCH REPORT | PROSPECTIVE STUDIES | COHORT ANALYSIS | FECUNDABILITY | TOBACCO USE | RISK FACTORS | Europe, Northern | Europe | Developed Countries | Studies | Research Methodology | Fecundity | Reproduction | Behavior | Biology Document Number: 139267 |
| 29. Title: Does moderate alcohol consumption affect fertility? Follow up study among couples planning first pregnancy. Author: Jensen TK; Hjollund NH; Henriksen TB; Scheike T; Kolstad H; Giwercman A; Ernst E; Bonde JP; Skakkebaek NE; Olsen J Source: BMJ (CLINICAL RESEARCH ED.). 1998 Aug 22;317(7157):505-10. Abstract: The effect of alcohol consumption on the probability of conception was investigated in a prospective study of 430 Danish couples seeking to achieve pregnancy for the first time. Couples were recruited through a national mailing to trade union members and followed for six menstrual cycles after contraception discontinuation or until a clinically recognized pregnancy occurred. Mean weekly alcohol intake was 4.0 drinks among women and 9.5 drinks among their male partners; 73 women (17%) abstained from alcohol drinking throughout the six cycles. During the study period, 179 (64%) of the 280 women with an average weekly alcohol intake of less than five drinks and 75 (55%) of the 136 women with a higher intake conceived. Among male partners, these rates were 67% and 58%, respectively. After adjustment for cycle number, smoking, enrollment center, diseases of the reproductive system, body mass index, sperm concentration, and menstrual cycle duration, the odds ratio decreased with increasing alcohol consumption from 0.61 (95% confidence interval, 0.40-0.93) among women who consumed 1-5 drinks a week to 0.55 (95% CI, 0.36-0.85) among those reporting 6-10 drinks a week to 0.34 (95% CI, 0.22-0.52) among women consuming 11-15 drinks a week compared with women with no alcohol intake. No dose-response relationship was found in male partners after adjustment for the same confounders. Although these findings require further corroboration, they suggest that even moderate alcohol consumption has a significant adverse effect on fecundability. Language: English Keywords: DENMARK | RESEARCH REPORT | PROSPECTIVE STUDIES | ALCOHOL USE AND ABUSE | FECUNDABILITY | RISK FACTORS | SIDE EFFECTS | Europe, Northern | Europe | Developed Countries | Studies | Research Methodology | Behavior | Fecundity | Reproduction | Biology | Treatment Document Number: 136200 |
| 30. Title: Declining fecundity and ovarian ageing in natural fertility populations. Author: O'Connor KA; Holman DJ; Wood JW Source: Maturitas. 1998 Oct 12;30(2):127-136. Abstract: Worldwide, human fertility declines with increasing maternal age, after contraceptive-use patterns and behavioral factors are taken into consideration. Here, we summarize some of our theoretical and empirical work examining the biological factors contributing to this age pattern of fertility. We undertook an 11 month prospective endocrinological study in a natural fertility (non-contracepting) population (rural Bangladesh) to estimate the contributions of fetal loss and fecundability (the probability of conception) to declining fecundity with age. Prospective interviews and urine samples for pregnancy tests were collected twice weekly from up to 700 women. These data were used to test mathematical models of the underlying biological processes contributing to changing fecundability and fetal loss risk with maternal age. The results indicate that much of the decline in fecundity can be attributed to an increasing risk of fetal loss with maternal age. Much of this fetal loss is due to chromosomal abnormalities--a result of ageing oocytes. Fecundability, on the other hand, does not begin to decline until the early 40s. We hypothesize that this is also a result of ageing at the ovarian level, namely follicular atresia, in the years just prior to menopause. The irregularity of menstrual cycles--longer cycles and increasingly variable hormonal patterns--at these ages may be a direct result of the small and rapidly dwindling remaining pool of follicles. We present a simple mathematical model of this process, and some preliminary laboratory results that support the model. (author's) Language: English Keywords: BANGLADESH | RESEARCH REPORT | PROSPECTIVE STUDIES | WOMEN | RURAL POPULATION | NONACCEPTORS | BIOLOGICAL AGING | SUBFECUNDITY | FERTILITY | OVARIAN EFFECTS | AGE FACTORS | CHROMOSOME ABNORMALITIES | Developing Countries | Asia, Southern | Asia | Studies | Research Methodology | Demographic Factors | Population | Population Characteristics | Family Planning Programs | Family Planning | Physiology | Biology | Fecundity | Reproduction | Population Dynamics | Ovary | Genitalia, Female | Genitalia | Urogenital System | Neonatal Diseases and Abnormalities | Diseases Document Number: 294558 |
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