Prospective study of birth interval dynamics in rural Bangladesh

A group of 209 married, fecund women in rural Bangladesh were studied prospectively for 24 months from 1969 to 1971 to define some of the biological and sociological factors relating to fertility performance. These women were selected from a larger study population of 112,000 that had been followed with a daily house-to-house vital registration programme since 1966. The selected women were interviewed bi-weekly and were asked questions about menstruation, pregnancy, lactation, husband's occupational absences, and monthly urine tests for pregnancy were taken. The results for 193 non-contracepting women revealed that the seasonal pattern of births previously observed in this population could be associated with a corresponding seasonal pattern of conceptions and that this was due to a seasonal trend in fecundability. The highest conception rates were in the coolest months of the year. Post-partum lactational amenorrhoea was very prolonged, averaging 17 months for women with a surviving child. The appearance of the first post-partum menstrual flow (onset of ovulation) also had a seasonal trend which could not be adequately explained. The median waiting time to conception, once menstruation had resumed was eight months. This interval was influenced by seasonal fluctuations, as well as by the age of women and by husbands' absences. The foetal wastage rate was 15·0 per 100 conceptions, with 62 per cent of the foetal losses occurring during the second month of gestation. Overall, the average birth interval was 33 months, with the prolonged lactational amenorrhoea accounting for almost 45 per cent of this interval.      

Pregnancy outcome and the time required for next conception

Abstract Variations in the time required for next conception by outcome ofthe preceding pregnancy, and the age of woman, are studied for Taiwanese women. Pregnancy interval, defined as the period between the end of one pregnancy and the beginning of the next, is taken as a measure of the time required for the next conception. The averages and variances of pregnancy intervals are estimated from reports of pregnancies occurring in a probability sample of 2,443 married women, aged 20-39, living in Taichung (Taiwan) in 1962. The effects of 'truncation bias' and 'memory bias' on the two moments of pregnancy intervals are estimated indirectly by cross-classifying women according to their ages at interview and their ages at the beginning (or end) of each pregnancy interval. The moments of post-partum amenorrhoea are, then, estimated indirectly from the moments of pregnancy intervals. The effects of truncation bias and memory bias are compensatory in this sample. In the absence of contraception, women, on an average, took longer to conceive following a live birth than following a foetal death. The time taken for next conception increases as women become older irrespective of the outcome of the preceding pregnancy.     

Nutrition and Fertility in Bangladesh: Breastfeeding and Post Partum Amenorrhoea

From 1975 to 1980 a prospective study a nearly 2,500 married, fertile women was conducted in Matlab, Bangladesh at the International Centre for Diarrhoeal Disease Research. Women were interviewed at monthly intervals to collect information on nutritional and reproductive status, in order to study the factors associated with natural fertility. The median duration of amenorrhoea for women with no child deaths was 15.5 months, with older women and those of higher parities recording longer durations than younger women or those of lower parities. Median duration of amenorrhoea for women with six or more years of education was 8.4 months compared to 16.4 months among women with no education. When classified by weight at pregnancy termination, average duration of amenorrhoea of women weighing less than 38 kg was 17.6 months compared to 13.6 months among women weighing more than 44 kg. Proportional hazards analyses show that mother's education, parity, month of birth, supplementation practices and nutritional status were significantly associated with the probability of resuming menstruation.     

Lactation and fertility in Rural Bangladesh

Summary Analysis of data from various phases of a study of post-partum amenorrhoea in Bangladesh illustrated good aggregate consistency of response on menstrual status, but less individual consistency on duration of post-partum amenorrhoea. Using life table techniques, the median duration of amenorrhoea was calculated as 19.9 months for women with births between February and September 1974. There were substantial seasonal variations in duration, with the median decreasing from 21.5 months for women with February births to 16.9 months for those with September births. By contrast, the median duration of post-partum amenorrhoea varies by only two months for women in the lowest and highest quartiles of weight and weight for height. The seasonal pattern was similar for all weight groups.     

Population planning in Asia in the 1970s

Analysis of data from various phases of a study of post-partum amenorrhoea in Bangladesh illustrated good aggregate consistency of response on menstrual status, but less individual consistency on duration of post-partum amenorrhoea. Using life table techniques, the median duration of amenorrhoea was calculated as 19.9 months for women with births between February and September 1974. There were substantial seasonal variations in duration, with the median decreasing from 21.5 months for women with February births to 16.9 months for those with September births. By contrast, the median duration of post-partum amenorrhoea varies by only two months for women in the lowest and highest quartiles of weight and weight for height. The seasonal pattern was similar for all weight groups.     

High foetal mortality and birth intervals

Abstract Studies of birth intervals have generally separated the process into: (1) the period of infertility following a pregnancy termination; (2) the length ofthe interval from the end of the infertile period to the next conception (which reflects the probability of conception), and (3) the average duration of pregnancy for both live births and foetal deaths.(1) Empirically derived intervals between successive live births average from 19 to 30 lunar months(2) (Table 1), depending upon the population studied and the birth order.(3) Estimates of conception rates using birth intervals data require some estimate of the extent to which foetal wastage increases the birth interval.     

Dynamics of contraceptive use and breastfeeding during the post-partum period in Peru and Indonesia

This paper examines the interaction between contraceptive use and breastfeeding in relation to resumption of intercourse and duration of amenorrhea post-partum. We used data from the month-by-month calendar of reproductive events from Demographic and Health Surveys (DHS) in Peru and Indonesia. The analyses show that breastfeeding women were less likely than non-breastfeeding women to have resumed sexual intercourse in the early months post-partum in both countries. In Peru, but not in Indonesia, breastfeeding women had a significantly lower odds than non-breastfeeding women of adopting contraception. Although the likelihood of contraceptive adoption was highest in the month women resumed menstruation in both countries, about ten per cent of subsequent pregnancies occurred to women before they resumed menses. These results emphasize the importance of integrating breastfeeding counselling and family planning services in programmes serving post-partum women, as a means of enabling those who wish to space their next birth to avoid exposure to the risk of a pregnancy that may precede the return of menses.     

A Family planning survey in four Delhi villages

A family planning attitude survey was conducted in four villages near metropolitan Delhi. Information was obtained through questionnaires from 455 currently married females of reproductive age: Of the women interviewed, 50 per cent were aware of family planning, 19 per cent had knowledge of a method and only 3 per cent used birth control methods. The method most commonly practised was prolonged lactation. Of the women interviewed, 253 were willing to learn about family planning; they said there was little opposition from their family members. These women thought that a family should have four children, and spacing between them should be roughly four years.     

The contribution of HIV to fertility decline in rural Zimbabwe, 1985-2000

HIV-related sub-fertility has been reported for those populations in sub-Saharan Africa in which contraceptive use is low. We use data from a retrospective survey in rural Zimbabwe and multivariate logistic regression models to show that recent birth rates and current pregnancy rates are also lower among HIV-positive women than among HIV-negative women in those African populations where contraceptive use is high. The fertility reduction is smaller than where contraceptive use is low because age at first sexual intercourse is later and birth rates at older ages are already low. Nevertheless, total fertility is approximately 8.5 per cent lower and HIV-associated sub-fertility may account for as much as one-quarter of fertility decline in Zimbabwe since the late 1980s. Mechanisms for HIV-associated sub-fertility in rural Zimbabwe include more frequent widowhood and divorce, reduced coital frequency, increased amenorrhoea, and possibly, pelvic inflammatory disease. Miscarriage appears to be a less important factor than elsewhere possibly because syphilis is rare.     

Seasonal Patterns of Reproduction in Matlab,Bangladesh

In Bangladesh twice as many births occur in December as in July. This paper examines the seasonal patterns of the risks of conception, fetal loss and return of menses post partum in a longitudinal study of 2,300 women in 14 villages of Matlab, Bangladesh. Life tables were estimated for each month of entry event and then ‘period’ life tables were constructed with the risks for a given calendar month. Confirming the results of earlier studies, risks of resumption of menses were higher in November and December, regardless of time elapsed since the last birth. Similarly, there are increased conception risks in the period from February to April for all fecundable women. The time of lowest fetal loss and stillbirth risks is in the cool season, though this variation makes only a minor contribution to the overall seasonality of births. The pattern of fecundability estimated from data on coital frequency did not match the pattern estimated from reported conceptions; these discrepancies imply possible seasonal changes in other parameters of fecundability besides intercourse.     

The island-wide family planning programme in Taiwan: Analysis of the accomplishments of the past eight years

Abstract Taiwan's island-wide family planning programme is the showcase of similar programmes in the developing world. In the past eight years, between 1964 and 1971, a cumulative total of 935,000 married women accepted the Lippes loop, 236,000 accepted the pill, and 116,000 couples accepted condoms. The prevalence rates of loop and pill users at the end of 1971 are estimated at 18·7 per cent and 3-6 per cent respectively. The programme had been recruiting more younger women of lower parity to practise family planning which is desirable, but a fact of concern is that a large proportion of the acceptors had had at least one son, and had accepted the methods to stop, rather than to space births. The 'life expectancy' of loop and pill, the two major contraceptives recommended in the programme, have been shorter than expected, 31·4 months without and 49·9 months with re-insertion for the loop, and only 10·5 months without re-taking for the pill. The concepts of 'half-life (retention)' and 'half-life (impact)', developed by the author, were applied in the analysis to obtain the values of 18·6 months and 25·7 months respectively for the loop, and 5·8 months and 9·2 months respectively for the pill all for the first segment. Only nine per cent of the total current loop wearers were aged 40-44 in 1964, but the proportion had increased substantially, to 20·5 per cent, in 1971. This 'ageing' of current users tends to minimize the demographic impact of the programme which is a factor of concern. Methods to overcome this and other problems should be explored for the final success of the programme.     

CharacteriStics and utilization of midwives in a selected rural area of East Pakistan

The purpose of this study was to obtain information about the utilization of midwives (dais) by village women and to learn more about the characteristics and practices of those dais. Two interview schedules were prepared. The first was used to interview 632 village women to determine who performed or assisted with their last two deliveries. The second was used to obtain information from 21 dais.The results of the first phase may be summarized as follows: (a) 38 per cent of the women were delivered by relatives; (b) 33 per cent of the women delivered their own children; (c) 14 per cent were delivered by neighbors; (d) 6 per cent were delivered by dais; (e) 2 percent were delivered in hospitals; and (f) the remaining 7 per cent were accounted for by several minor categories.The results of the interviews with dais are summarized as follows: (a) they are mainly widows and older women; (b) they have no formal training; (c) they work for friends, neighbors, and relatives and receive a sari as compensation; (d) they cannot handle complicated deliveries; (e) they deliver 3-4 children a year; (f) their sterilizing procedures depend upon soap, water, and folk beliefs; (g) most think midwifery is a worthwhile service; (h) about one-half have a general understanding of the reproduction process; (i) most do not know how to prevent conception; and (j) about half think that it is a good idea to participate actively in a family planning program.     

A model for estimating fecundability of the currently married woman from the data on her susceptibility status—A cohort approach

A probability model to estimate fecundability of a married woman has been proposed under some mild assumptions. It utilises the knowledge on the susceptibility status of the married women (including menstruation, menopause, pregnancy and amenorrhea) and therefore sets another approach for estimating fecundability. In addition, it is capable of predicting the parity, proportion of foetal losses, fecundability and incidence of secondary sterility. The problem of finding out the consistent estimates of the parameters in the distribution is discussed in section 4. For illustra-tion, the model is applied to a set of simulated data after simplifying many assumptions of the model     

Female sterilization in Aberdeen: Preliminary findings

2,500 women whose first marriage was continuing and who were living with their husbands at the time of hospital admission were sterilized in Aberdeen between 1963 and 1971. The social and demographic characteristics of these women are analysed, and a preliminary analysis by marriage cohort is presented. Those marriage cohorts in which sterilization was being performed for the first time mainly on young women with small families are identified. The family size of sterilized women was found to be substantially higher than that of women from the same marriage cohort who had not undergone the procedure. The contribution to total fertility made by the various forms of foetal wastage is assessed. Women whose sterilization was performed in association with a termination of pregnancy were found to have patterns of foetal loss which differed markedly from those of women who were not pregnant at the time of the operation.     

The effect of child mortality experience on subsequent fertility: in Pakistan and Bangladesh

Summary This paper presents an empirical analysis of the effects, behavioural and biological, of child mortality experience on subsequent fertility in two South Asian Islamic nations. Data for the investigation came from retrospective pregnancy histories of 2,910 currently married women interviewed in the Pakistan National Impact Survey (1968-69) and from longitudinal vital registration data (1966-2070) of 5,236 women residing in a rural area of Bangladesh collected by the Cholera Research Laboratory. The aim of this study was to assess the importance of the child-replacement motivational response to child death experience after biological effects have been controlled adequately. A common approach employed previously has been to examine cumulative fertility according to child death experience. In Pakistan and Bangladesh, a consistently positive relationship was demonstrated between the number of children ever born and the number of child deaths. This method, however, did not exclude the inverse relationship, the influence of fertility on mortality, nor did it dissect out behavioural from biological effects. Utilizing a measure of subsequent fertility, live-birth-to-live-birth intervals, the study further illustrated another common pitfall. Since the risk of infant death, which leads to shorter birth intervals, is associated with the mother's reproductive history, women with child mortality experience are more likely to experience shorter intervals because of the biological effect of subsequent infant death. Behavioural influences may, therefore, be observed by considering only those birth intervals in which the first-born child survives to the end of the interval. With these limitations controlled, very few, if any, behavioural influences were noted in the Pakistan and Bangladesh data. Median birth intervals in Pakistan varied between 35-43 and 41-42 months, increasing with parity. Within each parity group, no consistent difference was observed between women with and without previous child loss. In Bangladesh, the median birth interval for all women with a surviving infant was 37-2 months. This was shortened to 24-31 months by an infant death. When intervals with infant deaths were excluded, little or no behavioural influence was detected among women of the same parity, but with varying levels of previous child loss. Even without behavioural effects, elimination of infant mortality in Bangladesh would reduce fertility by prolonging the average period of post-partum sterility. In the Bangladesh setting, however, the size of the effect was only about four per cent. This modest effect, more-over, was counterbalanced by an overall increase of net reproduction by seven per cent due to better survivorship of infants.     

Cohort Trends in Premarital First Births: What Role for the Retreat From Marriage?

We examine cohort trends in premarital first births for U.S. women born between 1920 and 1964. The rise in premarital first births is often argued to be a consequence of the retreat from marriage, with later ages at first marriage resulting in more years of exposure to the risk of a premarital first birth. However, cohort trends in premarital first births may also reflect trends in premarital sexual activity, premarital conceptions, and how premarital conceptions are resolved. We decompose observed cohort trends in premarital first births into components reflecting cohort trends in (1) the age-specific risk of a premarital conception taken to term; (2) the age-specific risk of first marriages not preceded by such a conception, which will influence women’s years of exposure to the risk of a premarital conception; and (3) whether a premarital conception is resolved by entering a first marriage before the resulting first birth (a “shotgun marriage”). For women born between 1920–1924 and 1945–1949, increases in premarital first births were primarily attributable to increases in premarital conceptions. For women born between 1945–1949 and 1960–1964, increases in premarital first births were primarily attributable to declines in responding to premarital conceptions by marrying before the birth. Trends in premarital first births were affected only modestly by the retreat from marriages not preceded by conceptions—a finding that holds for both whites and blacks. These results cast doubt on hypotheses concerning “marriageable” men and instead suggest that increases in premarital first births resulted initially from increases in premarital sex and then later from decreases in responding to a conception by marrying before a first birth.     

Changes in union status during the transition to parenthood in eleven European countries, 1970s to early 2000s

Couples who have children are increasingly likely to have lived together without being married at some point in their relationship. Some couples begin their unions with cohabitation and marry before first conception, some marry during pregnancy or directly after the first birth, while others remain unmarried 3 years after the first birth. Using union and fertility histories since the 1970s for eleven countries, we examine whether women who have children in unions marry, and if so, at what stage in family formation. We also examine whether women who conceive when cohabiting are more likely to marry or separate. We find that patterns of union formation and childbearing develop along different trajectories across countries. In all countries, however, less than 40 per cent of women remained in cohabitation up to 3 years after the first birth, suggesting that marriage remains the predominant institution for raising children.     

The influence of child spacing on child survival

Summary This study evaluates the strength of the influence of spacing on child survival. Data related to a traditional culture (Punjab) in which almost all children are breast-fed up to the age of 17 months. An initial pregnancy history survey, subsequent four years updating through continuous monitoring of vital events and a second cross-sectional pregnancy history survey at the mid-point provided a file containing information on pregnancies and survival of children of 5,018 women. The analysis first looks at the correlation between the lengths of the preceding and subsequent intervals of index children, then examines whether this correlation was related to the repeated pattern of child death or survival. Next, the influence of the duration of the preceding interval on the survival of the index child in general and after accounting for the fate of the preceding child were considered. Then the influence of the length of the subsequent interval on the survival of the index child after conception and after the birth of the next child were studied. Lastly, regression analyses with preceding and subsequent intervals as independent variables and age-specific survival or death as the dependent variable were performed.