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: 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 |
| 3. 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 |
| 4. 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 |
| 5. Peer Reviewed Title: Social determinants of human reproduction. Author: ESHRE Capri Workshop Group Source: Human Reproduction. 2001;16(7):1518-26. Abstract: Developed countries have experienced both some population growth and unprecedented declines in fertility rates during the last half of the 20th century. Couples now have fewer than two children on average in most European countries and they tend to postpone these births until a later age. A decline in male fertility has been suggested by some studies of semen quality, but there is contrasting evidence of shorter times to pregnancy for couples trying to conceive. An important economic factor is the income of young men relative to their parents' incomes, which determines how they rate the ability of their own earnings to support a family. Lower relative income in the 1970s was associated with a lower fertility rate. The decline in fertility in the USA may have been attenuated by the sharp rise in female income during the late 1960s and early 1970s, allowing women to take advantage of purchased child care, thus maintaining the relative family income. The level of demand for children does not appear to be set by known psychological factors, although explanations for the desire to reproduce have been sought in biological, psychoanalytical and socio-cultural research. Recent studies indicate that adults with secure attachment relationships are more interested in being parents. Possible epidemiological factors include age at first marriage, but in eastern Europe, where age at the first marriage is as low as 22 years, fecundity rates do not exceed 1.5. When mothers' age cohorts are analyzed, the mean fecundity rate has been falling since the 1920s. Health factors affecting population trends include the change in contraceptive prevalence over the last 40 years. The prevalence of sub-fertility remains close to 10% and studies from a number of countries indicate that approximately 50% of infertile couples make use of infertility services including invitro fertilization and intracytoplasmic sperm injection which are available in 45 countries covering 78% of the world's population. It is estimated that the level of service is sufficient for less than one-third of the need. (author's) Language: English Keywords: DEVELOPED COUNTRIES | UNITED STATES OF AMERICA | EUROPE | BIRTH RATE | FERTILITY DECLINE | REPRODUCTION | COUPLES | FECUNDABILITY | FECUNDITY | HEALTH SERVICES | PROGRAMS | North America | Americas | Fertility Measurements | Fertility | Population Dynamics | Demographic Factors | Population | Fertility Changes | Family Characteristics | Family and Household | Delivery of Health Care | Health | Organization and Administration Document Number: 163122 |
| 6. 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 |
| 7. 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 |
| 8. 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 |
| 9. 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 |
| 10. 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 |
| 11. 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 |
| 12. 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 |
| 13. 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 |
| 14. Title: On estimation of fecundability from live birth history of women: an application of fecundity model. Author: Warvadekar J Source: Mumbai, India, International Institute for Population Sciences, 1999 Apr 20. 8, [8] p. Abstract: As defined by multilingual dictionary of demography, fecundity is the physiological capacity of women to conceive as well as fecundability refers to the monthly probability of conception in the absence of contraception. Using the fecundity model developed by Jain, an attempt is being done to study the relationship between age at marriage, marital duration and fecundability. Data were collected from the 1992-93 National Family Health Survey, in which 6254 married women of age group 13-49 was interviewed. Women in the age group 45-49, have currently married and sterilization is not adopted either by herself or her spouse, are selected. The fecundity model developed by Jain fits well for the cumulative fertility of Madhya Pradesh women, in the absence of contraception. It was also shown that age at marriage affects the levels of relative fecundability and the probability of giving a live birth while the physiological and behavioral factors are having their own effect over it. In the subgroup of early married women, the fecundability may be declined due to slightly greater effect of behavioral factors and among latter married women the effect of physiological changes are much greater than the effect of behavioral factors. Overall, the relative fecundability is a function of women's potentiality to conceive which depends on the three factors: women's age, age at marriage and duration of married life. Language: English Keywords: INDIA | RESEARCH REPORT | SURVEYS | ESTIMATION TECHNIQUES | REPRODUCTIVE BEHAVIOR | FECUNDABILITY | FECUNDITY | MARRIAGE AGE | MARRIAGE DURATION | Asia, Southern | Asia | Developing Countries | Sampling Studies | Studies | Research Methodology | Fertility | Population Dynamics | Demographic Factors | Population | Reproduction | Marriage Patterns | Marriage | Nuptiality Document Number: 169165 |
| 15. 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 |
| 16. 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 |
| 17. 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 |
| 18. 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 |
| 19. Title: Puberty and the family formation process in Sudan: age-at-menarche differential fecundity hypothesis revisited. Author: Otor SC; Pandey A Source: SOCIAL BIOLOGY. 1998 Fall-Winter;45(3-4):246-59. Abstract: Earlier studies have interpreted the difference in the onset of female pubertal maturation as indicative of biological differences in fecundity between early and late menarcheal women. The authors examine the ways in which the reproductive behavior of a woman is determined by how early or late in adolescence she enters puberty. Addressing the entire reproductive life of women, the authors study the transition from one parity to the next, as well as the speed of timing of reproduction, using birth intervals and parity progression ratios from which biological fecundity among women may be inferred. World Fertility Survey data for Sudan collected between December 1978 and April 1979 are used. Little evidence is found that early menarcheal women are more fecund than their late puberty counterparts. Language: English Keywords: SUDAN | RESEARCH REPORT | PUBERTY | WOMEN | MENARCHE | AGE FACTORS | FAMILY AND HOUSEHOLD | FECUNDITY | FECUNDABILITY | Africa, Northern | Africa | Developing Countries | Reproduction | Demographic Factors | Population | Menstruation | Population Characteristics Document Number: 140649 |
| 20. Title: Predictors of fecundability and conception waits among the Dogon of Mali. Author: Strassmann BI; Warner JH Source: AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY. 1998 Feb;105(2):167-84. Abstract: Female fertility in the Dogon village of Sangui, Mali, was studied by focusing upon the waiting time to conception during menstrual cycling among 50 women aged 16-41 years over 736 consecutive days. Sangui had a pronatalist and noncontracepting population of 460 as of January 1988. In accordance with animist beliefs, the women of Sangui spend 5 nights sleeping at a menstrual hut during menses. The women's conception waits were monitored prospectively by surveying the women present at the two menstrual huts in the study village on each of 736 consecutive nights from July 1986 to July 1988. 33 of 50 women observed became recognizably pregnant during the study, while 25 women cycled without becoming pregnant. Hormonal profiles confirm the accuracy of the data on conception waits obtained from the menstrual hut census. The following factors were significant predictors in the continuous time model of the waiting time to conception: wife's age, husband's age, marital duration, gravidity, and breast-feeding status. Additional variables were not significant, including duration of postpartum amenorrhea, sex of the last child, nutritional status, economic status, polygyny, and marital status. Language: English Keywords: MALI | RESEARCH REPORT | FECUNDABILITY | FERTILIZATION | TIME FACTORS | AGE FACTORS | MARITAL STATUS | PREGNANCY RATE | BREASTFEEDING | Developing Countries | Africa, Western | Africa, Sub Saharan | Africa | Fecundity | Reproduction | Population Dynamics | Demographic Factors | Population | Population Characteristics | Nuptiality | Fertility Measurements | Fertility | Infant Nutrition | Nutrition | Health Document Number: 132139 |
| 21. Title: Extent of infecundity derived from open birth interval data. Author: Yadava RC; Srivastava M Source: DEMOGRAPHY INDIA. 1998 Jan-Jun;27(1):205-11. Abstract: This study offers a methodology to estimate the proportion of fecund females among women with an open birth interval. Methods are based on the work of Srinivasan (1967), Yadava and Saxena (1989), Yadava and Bhattacharya (1985), and Yadava et al. (1992). The proposed method assumes no fertility decline over time, and that women after giving birth may remain either fecund or sterile throughout the observation period by any means. The proposed method was tested with data from a 1978 demographic survey among about 3500 currently married females aged 15-49 years from rural Varanasi in India. Findings suggest the proportion of fecund females having open birth intervals between 5-10 years was small for parities of 3 or higher. With an open birth interval of 7-10 years, the proportion of fecund females was very small. The low fertility among the aforementioned populations means that family planning is not likely to reduce fertility, but will help women maintain a longer open interval. Language: English Keywords: INDIA | RESEARCH REPORT | METHODOLOGICAL STUDIES | SURVEYS | RURAL POPULATION | ESTIMATION TECHNIQUES | FECUNDABILITY | OPEN LIVE-BIRTH INTERVALS | PARITY PROGRESSION RATIO | Asia, Southern | Asia | Developing Countries | Sampling Studies | Studies | Research Methodology | Population Characteristics | Demographic Factors | Population | Fecundity | Reproduction | Birth Intervals | Fertility Measurements | Fertility | Population Dynamics | Parity Document Number: 137988 |
| 22. Title: The probability of conception on different days of the cycle with respect to ovulation: an overview. Author: Ferreira-Poblete A Source: ADVANCES IN CONTRACEPTION. 1997 Jun-Sep;13(2-3):83-95. Abstract: Several mathematical models have been developed to determine the probability of conception on different days of the menstrual cycle and to estimate the day of ovulation. One group of models (Barrett and Marshall, Schwartz) extends the concept of cycle viability to allow for differences between cycles within couples and for the introduction of couple covariates. In a second group of models (Royston, Weinberg and Wilcox), the probability of conception depends mainly on the time of intercourse and the survival times of sperm and ovum. The probability of conception is greatest from 5 days before ovulation to the day of ovulation. Since the mean survival of the ovum has been estimated at 0.7 days, the width of the fertile window is likely due to the survival of sperm and the inaccuracy of estimated times of ovulation. Cycle viability estimates range between 0.57 for the Barrett-Marshall data found by Royston to 0.37 for the data found by Wilcox. The mean survival of sperm is 1.4-1.5 days, but significant probabilities of conception up to 5 days before ovulation imply that the survival distribution of sperm falls off very slowly. Further work is needed in the area of daily conception probabilities to obtain biologically sensible models and to examine covariates that could be included in these models. Further research should also look at modeling cycle viability as a continuous outcome rather than as a dichotomous event. Language: English Keywords: LITERATURE REVIEW | MATHEMATICAL MODEL | OVULATION DETECTION | MENSTRUAL CYCLE | FERTILE PERIOD | PROBABILITY | FERTILIZATION | FECUNDABILITY | Theoretical Models | Research Methodology | Laboratory Procedures | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Menstruation | Reproduction | Statistical Studies | Studies | Fecundity Document Number: 127407 |
| 23. Title: Estimation of fecundability: levels of trends in Bangladesh. Author: Islam MM; Yadava RC Source: Journal of Family Welfare. 1997 Sep;43(3):13-20. Abstract: The concept of fecundability - the monthly probability of conception in women - is one of the principal determinants of fertility and one of the most important parameters for studying fertility patterns in different societies. Fecundability affects fertility through its relationship with the average time required for a conception to occur, and can also be thought of as the transition probability for the passage from the susceptible state to pregnancy. In practice, fecundability is measured in women who are ovulating regularly, that is, pregnant, sterile or post-partum, anovulatory women are excluded. The term natural fecundability is used non-contracepting populations; 'total (or physiological)' fecundability considers all conceptions regardless of outcome, including non-implanted fertilized ova and conceptions aborted spontaneously before the end of the cycle, while 'recognizable' fecundability relates to conceptions recognizable at the end of the conception cycle by the non-occurrence of menstruation, and 'effective' fecundability includes only pregnancies ending in live births. In this study, the term 'fecundability' mainly refers to effective fecundability. (excerpt) Language: English Keywords: BANGLADESH | MATHEMATICAL MODEL | WOMEN | FECUNDABILITY | DIFFERENTIAL FERTILITY | FAMILY SIZE, DESIRED | Asia, Southern | Asia | Developing Countries | Theoretical Models | Research Methodology | Demographic Factors | Population | Fecundity | Reproduction | Fertility | Population Dynamics | Family Size | Family Characteristics | Family and Household Document Number: 281241 |
| 24. Title: Probability of conception on different days of the menstrual cycle: an ongoing exercise. Author: Masarotto G; Romualdi C Source: ADVANCES IN CONTRACEPTION. 1997 Jun-Sep;13(2-3):105-15. Abstract: The European Multicenter Study is providing estimates of the probability of conception on a given day of the menstrual cycle conditional to unprotected intercourse occurring only on that specific day. To date, this prospective study has collected data on 468 pregnancies and 6434 cycles from 767 women recruited from 7 European centers that teach the symptothermal method of natural family planning. An analysis of the data set from the Verona, Italy, center (1042 charts collected by 169 couples with 125 conceptions) considered 4 covariates: the woman's age, the man's age, the number of children, and the number of days with most fertile mucus during the fertile window. Estimates of the probabilities of conception were lower than those previously reported in the literature. The man's age (but not the woman's) affected the probability of conception. The number of children also affected fecundity, presumably in its role as a proxy for the differences in biological capability to conceive between couples not explained by the other covariates. The patterns of the probabilities of conception were similar for the basal body temperature (BBT) rise and the mucus peak, although the fitted probabilities decreased faster when BBT was used. The results suggest use of a model of fecundity based jointly on BBT and mucus. Language: English Keywords: ITALY | THEORETICAL STUDIES | MATHEMATICAL MODEL | MENSTRUAL CYCLE | OVULATION DETECTION | PROBABILITY | FERTILIZATION | FECUNDABILITY | FERTILE PERIOD | SYMPTO-THERMAL METHOD | CERVICAL MUCUS | Europe, Southern | Europe | Developed Countries | Theoretical Models | Research Methodology | Menstruation | Reproduction | Laboratory Procedures | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Statistical Studies | Studies | Fecundity | Natural Family Planning | Family Planning, Behavioral Methods | Family Planning | Cervix | Uterus | Genitalia, Female | Genitalia | Urogenital System | Physiology | Biology Document Number: 127405 |
| 25. Title: Infertility treatment and multiple birth rates in Britain, 1938-94. Author: Murphy M; Hey K; Brown J; Willis B; Ellis JD; Barlow D Source: JOURNAL OF BIOSOCIAL SCIENCE. 1997 Apr;29(2):235-43. Abstract: "Trends in multiple birth rates are thought to have been substantially affected by subfertility treatments in the last 25 years, but there are few quantitative assessments of this. This paper examines trends in twin and higher multiple birth rates separately in Scotland, England and Wales and compares their course with corresponding multiple birth rates in the Oxford Record Linkage Study area, where the proportions following subfertility treatment are documented. National data on prescriptions for subfertility treatments reinforce the view that they have had a major effect on the trends, and currently perhaps 60% of triplet and higher order births and 15% of twins follow their use in Britain." (EXCERPT) Language: English Keywords: UNITED KINGDOM | MULTIPLE BIRTH | COMPARATIVE STUDIES | FECUNDABILITY | SUBFECUNDITY | INFERTILITY | TREATMENT | PREVENTION AND CONTROL | Developed Countries | Europe, Western | Europe | Reproduction | Studies | Research Methodology | Fecundity | Diseases Document Number: 171030 |
| 26. Peer Reviewed Title: Model-based approaches to studying fertility and contraceptive efficacy. Author: Weinberg CR; Zhou H Source: ADVANCES IN CONTRACEPTION. 1997 Jun-Sep;13(2-3):97-103. Abstract: Proposed in this paper are new approaches to the design and analysis of contraceptive clinical trials. Although these models were developed to allow identification of environmental exposures with reproductive toxicity, they can be used to evaluate contraceptive exposures that impair fecundability through cycle control or sperm obstruction. Another application is to evaluate putative markers for the fertile phase (e.g., mucus properties) that can be used to improve methods based on periodic abstinence. These approaches are applicable in settings where intercourse is unrestricted and daily coital logs are maintained by participating couples, and where the investigator has available a reliable benchmark for dating ovulation. For methods used sporadically (e.g., condoms), the new approaches allow simultaneous estimation of both the relevant fertility parameters and the contraceptive efficacy parameters. Language: English Keywords: THEORETICAL STUDIES | MATHEMATICAL MODEL | CLINICAL TRIALS | CONTRACEPTION RESEARCH | PROBABILITY | FECUNDABILITY | FERTILE PERIOD | CONTRACEPTIVE EFFECTIVENESS | MENSTRUAL CYCLE | OVULATION DETECTION | Theoretical Models | Research Methodology | Clinical Research | Contraception | Family Planning | Statistical Studies | Studies | Fecundity | Reproduction | Menstruation | Laboratory Procedures | Laboratory Examinations and Diagnoses | Examinations and Diagnoses Document Number: 127406 |
| 27. Title: Incidence and implications of altered semen quality on family planning. Author: Zinaman MJ; Katz DF Source: ADVANCES IN CONTRACEPTION. 1997 Jun-Sep;13(2-3):123-8. Abstract: Toxic environmental exposures have been demonstrated to have an adverse effect on the male reproductive system in animal studies. No single measure of human sperm quality can ensure that the cell is functionally competent. Recent suggestions of a deterioration in human semen quality have not been confirmed; however, any decrements in semen quality would alter the probabilities of pregnancy due to coitus on different cycle days and thereby change the duration of the fertile period. A prospective study of 210 normally fertile US couples who desired pregnancy was initiated in 1987. During the first 3 months of study enrollment, 116 (58%) of the 200 couples for whom data were analyzed conceived. By the end of the first year, 163 couples (82%) had conceived. An analysis of the proportion of couples who conceived in the first 3 months stratified by the sperm concentrations of the male revealed a consistent increase in pregnancies with increasing sperm counts except at the highest levels. Representing the non-normally distributed semen concentration by a spline fit or logarithmic transformation gave the most suitable representation of the relationship between sperm concentration and pregnancy in couples who conceived rapidly versus those who did not. In both cases, significant declines in rapid conceptions appeared at sperm concentrations under 40 million. Future findings of this study should provide information to guide natural family planning use. Language: English Keywords: UNITED STATES OF AMERICA | PROSPECTIVE STUDIES | CLINICAL RESEARCH | SEMEN | SPERM COUNT | FERTILIZATION | FECUNDABILITY | NATURAL FAMILY PLANNING | Developed Countries | North America | Americas | Studies | Research Methodology | Seminal Vesicles | Genitalia, Male | Genitalia | Urogenital System | Physiology | Biology | Laboratory Procedures | Laboratory Examinations and Diagnoses | Examinations and Diagnoses | Reproduction | Fecundity | Family Planning, Behavioral Methods | Family Planning Document Number: 127403 |
| 28. Title: Effects of a behavioural rhythm on conception probability and pregnancy outcome. Author: Boklage CE Source: HUMAN REPRODUCTION. 1996 Oct;11(10):2276-84. Abstract: Time series analyses have identified a weekday rhythm in human conception rates. The present analysis was based on 1.2 million North Carolina birth records for all deliveries beyond 18-20 weeks of gestation in the years 1979-91; 83% included a usable last menstrual period date. In the average week, coital frequency peaks between midnight Saturday and noon on Sunday, resulting in a clear excess of conceptions in cycles that have their 14th day on a Sunday. There was a secondary peak of births from cycles that began on Fridays. Average cycles that began on Monday had their most fertile day on the most likely day for intercourse, translating a weekly insemination rhythm into a weekly conception rate rhythm. The secondary conception peak in Friday-onset cycles increased with age, to become the major peak for mothers over 30 years of age. This finding suggests the presence of a previously unreported second type of cycle with a modal follicular phase length of 10 days, the frequency of which increases with age. Advancing maternal age may increase the frequency of birth anomalies through an increased probability of fertilizations that are poorly timed relative to oocyte maturation. Language: English Keywords: NORTH CAROLINA | UNITED STATES OF AMERICA | RESEARCH REPORT | STATISTICAL STUDIES | TIME FACTORS | MENSTRUAL CYCLE | OVULATION | CONGENITAL ABNORMALITIES | MATERNAL AGE | FERTILIZATION | FERTILE PERIOD | FECUNDABILITY | Developed Countries | North America | Americas | Studies | Research Methodology | Population Dynamics | Demographic Factors | Population | Menstruation | Reproduction | Neonatal Diseases and Abnormalities | Diseases | Parental Age | Age Factors | Population Characteristics | Fecundity Document Number: 119091 |
| 29. Title: Effects of age at marriage on fertility and mortality in rural Bangladesh. Author: Chowdhury MK; Bairagi R; Suchindran CM Source: Chapel Hill, North Carolina, University of North Carolina at Chapel Hill, Carolina Population Center [CPC], 1996 Jan. 11 p. (Paper No. 96-1) Abstract: This article presents a study on the effects of age at marriage on fertility and infant and maternal mortality in Matlab, Bangladesh. Data on a cohort of 4650 women first wed during 1977-79 were analyzed and followed for the subsequent 12 years for live births. Analyses of live birth intervals, monthly average number of births through age 25, and average number of births per woman occurring during the last 5 years of the first 10 years of follow-up indicated that fecundability remained unchanged through the mid-1920s, no matter what age a woman first married. However, follow-up evinced a decline in fecundability beyond the mid-1920s, suggesting that increased age at marriage could have potential for fertility reduction. These results, when paired with the limited use of contraceptives noted during follow-up, show a marginal difference in effect on fertility. This underscores the point that with mean age at marriage rising to some adequately high level, the existing minimum age at marriage in the area will have little or no significance for fertility. In conclusion, it is necessary to integrate efforts that seek higher ages at marriage with those seeking increased spacing between births through family planning services. Language: English Keywords: BANGLADESH | RESEARCH REPORT | COHORT ANALYSIS | AGE FACTORS | FERTILITY | INFANT MORTALITY | MATERNAL MORTALITY | RURAL POPULATION | MARRIAGE AGE | FECUNDABILITY | DEATH RATE | Asia, Southern | Asia | Developing Countries | Research Methodology | Population Characteristics | Demographic Factors | Population | Population Dynamics | Mortality | Marriage Patterns | Marriage | Nuptiality | Fecundity | Reproduction Document Number: 147324 |
| 30. Title: Total fecundability and fetal loss in rural Bangladesh. Author: Holman DJ Source: Ann Arbor, Michigan, UMI Dissertation Services, 1996. [2], xvii, 321 p. (UMI No. 9628104) Doctoral dissertation, Pennsylvania State University, 1996. Abstract: This study presents an evaluation of a variety of methods and models for determining fetal loss and fecundability. The model used in this analysis is an extension of the Wood-Boklage model and incorporates incomplete sensitivity, incomplete specificity, and fecundability as important parameters that affect estimation. The model was tested on data obtained from 28 villages within Matlab in rural Bangladesh. The study includes a 1-month baseline survey, a 9-month follow-up survey, and a 6-week anthropometric survey. A short coital frequency survey was conducted among a sample of subjects. Urine samples from 15 women were collected and analyzed continuously and periodically over 3 days. The best estimates from the Wood-Boklage model were in general agreement with the best estimates from the modified model including fecundability. False-positive pregnancy diagnoses resulted in estimates of higher risk of fetal loss for the Wood-Boklage model. Estimates were similar between both Wood-Boklage models and the Wilcox et al. study. Fecundability was low until the age of 15 years, increased, and then declined rapidly after 42 years of age. Age-specific fecundability validated the same general pattern as the Wood-Weinstein maximal exposure model. However, the drop off was sharper and over a narrower range. The risk of fetal loss and fecundability was found to be high at all ages. Women recognized their pregnancy in the mean time of 48 days from conception. An 18-year-old woman had about a 40% chance of fetal loss for any conception. Loss rates were up to 95% by the late 40s. The mean length of gestation at the mean maternal age was 15 days. Findings suggest that development of a reliable and rapid way to screen preimplantation embryos for chromosomal disorders and specific genetic disorders would improve success rates of in vitro fertilization. Language: English Keywords: BANGLADESH | RESEARCH REPORT | FETAL DEATH | FECUNDABILITY | RESEARCH METHODOLOGY | THEORETICAL MODELS | LIFE TABLE METHOD | BASELINE SURVEYS | ANTHROPOMETRY | SEXUAL INTERCOURSE | LABORATORY PROCEDURES | Asia, Southern | Asia | Developing Countries | Mortality | Population Dynamics | Demographic Factors | Population | Fecundity | Reproduction | Demographic Analysis | Surveys | Sampling Studies | Studies | Measurement | Laboratory Examinations and Diagnoses | Examinations and Diagnoses Document Number: 119222 |
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