A Prospective Study of Birth Interval Dynamics in Rural Bangladesh

Abstract

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. From the Department of Population Dynamics, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland 21205.

Birth Intervals, Survival and Growth in a Nigerian Village

“…A previous paper by Martin, Morley & Woodland (1964) described the birth interval of the area, and discovered an unexpectedly high overall mean interval of 35-5 months following the birth of a child who survived to 1 year. Since then, other studies from developing populations have produced estimates of birth intervals approaching 3 years (Potter et al, 1965;Cantrelle & Leridon, 1971;Chen et al, 1974). In this paper evidence will be presented from more extensive and recent data from Imesi to confirm the results first presented by Martin et al (1964), and to investigate the relationship between the birth interval and other variables, especially the survival and growth of the child.…”

Spousal separation, selectivity and contextual effects: exploring the relationship between international labour migration and fertility in post-Soviet Tajikistan

“…At an aggregate level, van de Walle (1975) links the relatively low levels of marital fertility in nineteenth century Ticino, Switzerland to the regular seasonal pattern of male absence. Massey and Mullan (1984) use cross-sectional individual-level data from a rural town in Mexico to show that women with husbands absent through migration (leaving at some point between 1976 and 1978) were significantly less likely to have a child aged one or two (born in 1976 and 1977), while Chen et al (1974) argue that monthly variation in the number of days males are absent partially explains the striking seasonal pattern in births found in Matlab, Bangladesh over the two-year observation period.…”

Malnutrition and Fertility

“…Sociobiol. 6 (1). Also, seasonal variations in plasma prolactin and milk yield were associated with significant differences in maternal nutrition and physical labor and were not explained by the frequency of infant feeding (1,3,4).…”

“…In a prospective study in Bangladesh, Chen et al (6) found that the median duration of lactational amenorrhea with a surviving child was 17 months. This long period was related both to child feeding practices and to the poor nutritional status of the mother and child.…”

“…Supplementing the nursing infant's diet shortens lactational amenorrhea (1)(2)(3)(4). As the periods of breast-feeding shorten and the intensity of suckling declines, the concentration of the ovulation-inhibiting hormone prolactin also declines, eventually resulting in the return of normal ovulatory function (1,(5)(6)(7)(8). The question at issue is whether the mother's nutritional status can influence amenorrhea if breast-feeding and suckling patterns are unchanged.…”