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PubMed2006

[Effects of the late marriage of Korean women on the first-birth interval].

OBJECTIVES: The purpose of this study was to examine the effect of women's late age of marriage on the interval between marriage and their first birth. METHODS: Data from Year 2000 Korea National Fertility Survey was collected through direct interview questionings, and the data was analyzed based on randomly selected sampling. In particular, the married women (N=5,648) were analyzed for the factors that determined the first-birth interval by performing Cox's proportional hazard model survival analysis. RESULTS: Unlike previous findings, the woman whose age of marriage was 30 or more was more likely to delay the birth of her first baby than were the other women who married earlier. Further, a woman's age at marriage, a woman's residence before marriage, her husband's religion, her husband's level of education and the difference in age between the woman and her husband significantly influenced the first-birth interval. In contrast, for a married woman, her age, level of education, current residence and religion were not significant predictors of her first birth interval. CONCLUSIONS: Our study showed that women who married at the age of 30 years or more tend to postpone their first birth in Korea. When facing the increasing number of women who marry at a late age, the Korean government should implement population and social policies to encourage married women have their first child as early as possible.

Adult↗

PubMed1993

On the estimates of the fecundability from interlive birth interval data.

"This study derives some probability models for all closed birth intervals and last closed birth intervals under [the] same set of assumptions. The models have been applied to some observed data taken from [India's] Varanasi Survey (1978). Models considered for analysis are presented in section two of the paper while section three deals with [the] illustration of models."

Asia↗

PubMed1993

Age of marriage and length of the first birth interval in a traditional Indian society: life table and hazards model analysis.

The length of the first birth interval is one of the strongest and most persistent factors affecting fertility in noncontracepting populations, with longer intervals usually associated with lower fertility. Compared to Western society, the average length of the first birth interval is much longer in traditional Indian society. Yet Indian fertility rates are higher because of either ineffective family planning procedures or deliberate nonuse of birth control and because of the high proportion of the population that is married. Here, we examine the effects of various sociodemographic covariates (with an emphasis on the role of age at marriage) on the length of the first birth interval for two states of India: Assam and Uttar Pradesh. Life table and multivariate hazards modeling techniques are applied to the data. Covariates such as age at marriage, present age of mother, female's occupation, family income, and place of residence have strong effects on the variation of the length of the first birth interval. For each subgroup of females (classified according to different levels of the covariates), the median length of the first birth interval for the Assam (Bengali-speaking) sample is shorter than that of the Uttar Pradesh (Hindi-speaking) sample.

Adolescent↗

PubMed2005

Changes in marriage age and first birth interval in Huaning County, Yunnan Province, PR China.

The timing of marriages, first birth interval and the prevalence of premarital conception (PMC) among women of successive birth cohorts in one rural county in Yunnan, China, were examined. Detailed pregnancy histories were collected for 1,336 women aged 15-64 years using a Life History Calendar. The rising marriage age and shorter first birth interval correspond to over-all changes in the Chinese society over the same time period. The mean age at first marriage for women born before 1950 was just below 20, and 22.5 among women born 1976-1980. The later marriage age was partly offset by the dramatic shortening of the first birth interval from over 30 months in the oldest cohort to 11-12 months in the youngest. One explanation of the shortening of the first birth interval may be the increase in premarital conception. Among the young women in our study almost one-third of first pregnancies were conceived before marriage.

Adolescent↗

PubMed1996

Birth interval and pregnancy outcome.

A cross-sectional study was conducted from September to March 1993 at maternity ward of Jimma Hospital to asses the pattern and determinants of birth interval and the role of contraceptive in influencing the length of birth interval. The information was collected by use of pre-tested questionnaire from 415 mothers by three midwives trained for this purpose. The variables examined were: information on parity, use of contraceptive methods during the preceding birth intervals, breast feeding and some demographic variables such as age, martial status, education. Pregnancy outcome variables such as, live births, stillbirths, abortion and infant deaths. Slightly over seventy five per cent of the study subjects were aged 20-29 years, 59% and 27% were para 2-3 and 4-5 respectively. In more than 81% of the subjects, the birth interval was less than three years with a mean birth interval of 22.1 months. Approximately two per cent used contraceptive when the birth interval was 12 months and less. Stillbirth and early neonatal deaths accounted for 3.2% and 6.9% respectively. Based on the findings, we underscore the importance of birth spacing using the available family planning methods to promote safe motherhood and achieve better child survival.

Adult↗

PubMed1990

Birth intervals and childhood mortality in rural Bangladesh.

This study investigates the relationship between birth intervals and childhood mortality, using longitudinal data from rural Bangladesh known to be of exceptional accuracy and completeness. Results demonstrate significant but very distinctive effects of the previous and subsequent birth intervals on mortality, with the former concentrated in the neonatal period and the latter during early childhood. The impact of short birth intervals on mortality, however, is substantially less than that found in many previous studies of this issue, particularly for the previous birth interval. The findings are discussed in terms of the potential for family planning programs to contribute to improved child survival in settings such as Bangladesh.

Bangladesh↗

PubMed1993

Analysis of birth intervals in India's Uttar Pradesh and Kerala States.

Life tables of birth intervals and median birth intervals in two Indian states, Uttar Pradesh and Kerala, were computed for several subgroups of the study population. Multivariate hazards modelling technique was used to examine the net effect of each of the variables studied. The results show a substantial effect of socioeconomic variables in child-spacing after controlling for the major intermediate variables.

Adolescent↗

PubMed2005

Effects of preceding birth intervals on neonatal, infant and under-five years mortality and nutritional status in developing countries: evidence from the demographic and health surveys.

OBJECTIVE: This paper examines the association between birth intervals and infant and child mortality and nutritional status. METHODS: Repeated analysis of retrospective survey data from the Demographic and Health Surveys (DHS) program from 17 developing countries collected between 1990 and 1997 were used to examine these relationships. The key independent variable is the length of the preceding birth interval measured as the number of months between the birth of the child under study (index child) and the immediately preceding birth to the mother, if any. Both bivariate and multivariate designs were employed. Several child and mother-specific variables were used in the multivariate analyses in order to control for potential bias from confounding factors. Adjusted odds ratios were calculated to estimate relative risk. RESULTS: For neonatal mortality and infant mortality, the risk of dying decreases with increasing birth interval lengths up to 36 months, at which point the risk plateaus. For child mortality, the analysis indicates that the longer the birth interval, the lower the risk, even for intervals of 48 months or more. The relationship between chronic malnutrition and birth spacing is statistically significant in 6 of the 14 surveys with anthropometric data and between general malnutrition and birth spacing in 5 surveys. However, there is a clear pattern of increasing chronic and general undernutrition as the birth interval is shorter, as indicated by the averages of the adjusted odds ratios for all 14 countries. CONCLUSION: Considering both the increased risk of mortality and undernutrition for a birth earlier than 36 months and the great number of births that occur with such short intervals, the author recommends that mothers space births at least 36 months. However, the tendency for increased risk of neonatal mortality for births with intervals of 60 or more months leads the author to conclude that the optimal birth interval is between 36 and 59 months. This information can be used by health care providers to counsel women on the benefits of birth spacing.

Birth Intervals↗

PubMed1990

Birth interval among breast-feeding women not using contraceptives.

One hundred twelve Orthodox Jewish mothers were surveyed by means of questionnaire about birth interval in relationship to formula-feeding (n = 30) and breast-feeding (n = 236) experiences in the absence of birth control. Analyses indicate that mothers who breast-fed have longer birth intervals than those who did not. Moreover, data obtained from the same mothers show that birth intervals preceded by breast-feeding were longer than those preceded by formula-feeding of the previous infant. For those mothers who breast-fed, there was significant positive correlation between duration of breast-feeding and the length of lactational amenorrhea and total birth interval. The age at which night feeding was terminated had corresponding but less strong associations with lactational amenorrhea and total birth interval.

Adult↗

PubMed2000

The effect of birth interval on malnutrition in Bangladeshi infants and young children.

This study was undertaken to investigate the independent effect of the length of birth interval on malnutrition in infants, and children aged 6-39 months. Data for this study were drawn from a post-flood survey conducted during October-December 1988 at Sirajganj of the Sirajgani district and at Gopalpur of the Tangail district in Bangladesh. The survey recorded the individual weights of 1887 children. Cross-tabulations and logistic regression procedures were applied to analyse the data. The proportion of children whose weight-for-age was below 70% (moderate-to-severely malnourished) and 60% (severely malnourished) of the NCHS median was tabulated against various durations of previous and subsequent birth intervals. The odds of being moderately or severely malnourished were computed for various birth intervals, controlling for: the number of older surviving siblings; maternal education and age; housing area (a proxy for wealth); age and sex of the index child; and the prevalence of diarrhoea in the previous 2 weeks for the index child. About one-third of infants and young children were moderately malnourished and 15% were severely malnourished. The proportion of children who were under 60% weight-for-age decreased with the increase in the length of the subsequent birth interval, maternal education and housing area. The proportion of malnourished children increased with the number of older surviving children. Children were at higher risk of malnutrition if they were female, their mothers were less educated, they had several siblings, and either previous or subsequent siblings were born within 24 months. This study indicates the potential importance of longer birth intervals in reducing malnutrition in children.

Adult↗

PubMed1993

Short birth intervals: the experience of Bangladeshi immigrants to the United Kingdom, 1974 through 1984.

Linked maternity data were used to calculate birth intervals from records of 7129 consecutive singleton births to Bangladeshi mothers who delivered in the London borough of Tower Hamlets from 1974 through 1984. During this period, there was active migration of women from Bangladesh, the majority coming to the United Kingdom as brides or young wives. Risk of a subsequent birth was calculated using life tables, and results were compared to national data from Bangladesh and the United Kingdom. The risk of a subsequent birth within 12 and 18 months for Bangladeshi women was twice that reported nationally for women in Bangladesh or in the United Kingdom, despite a demonstrable underestimation inherent in the method. The risk of short birth intervals was lower in the first 5 years than in the later years covered by the investigation. Short intervals stress maternal and infant health and are preventable. Possible explanations for the unusual excess of very short birth intervals include: (1) the wide availability of artificial milk in a community that has traditionally used breast-feeding as the main method of spacing pregnancies and (2) confusion regarding appropriate postnatal contraception in a young, healthy married population.

Bangladesh↗

PubMed2006

Short birth intervals and the risk of school unreadiness among a Medicaid population in South Carolina.

BACKGROUND: Communities across the United States have become more involved in enhancing school readiness. Many of the predictors of school readiness relate to conditions prior to and following the birth of the child, including a child's birthweight. Shortened birth intervals are related to a variety of health and social consequences that affect child development, yet no formal research has examined the association between birth intervals and school readiness. METHODS: This study was a secondary data analysis of de-identified pregnancy-related vital record information, matched to selected items from the Department of Health and Human Services Medicaid records on mothers and children and to the Cognitive Skills Assessment Battery score in South Carolina for the year 2000 for the child of interest (N = 6915). Analysis of covariance and logistic regression were used to determine if there was a statistically significant relationship between birth interval and school readiness. RESULTS: Results showed that birth interval is a significant predictor of school readiness with a P-value <0.001 even after controlling for various socio-demographic factors. Children born with inadequate birth intervals (less than 24 months) are more likely to fail the Cognitive Skills Assessment Battery compared with those with adequate birth intervals. Potential implications of this research include promoting optimal birth spacing to improve the likelihood that future first graders will come to school ready to learn.

Adult↗

PubMed2000

Determinants of birth interval in a rural Mediterranean population (La Alpujarra, Spain).

The fertility pattern, in terms of birth intervals, in a rural population not practicing contraception belonging to La Alta Alpujarra Oriental (southeast Spain) is analyzed. During the first half of the 20th century, this population experienced a considerable degree of geographical and cultural isolation. Because of this population's high variability in fertility and therefore in birth intervals, the analysis was limited to a homogenous subsample of 154 families, each with at least five pregnancies. This limitation allowed us to analyze, among and within families, effects of a set of variables on the interbirth pattern, and to avoid possible problems of pseudoreplication. Information on birth date of the mother, age at marriage, children's birth date and death date, birth order, and frequency of miscarriages was collected. Our results indicate that interbirth intervals depend on an exponential effect of maternal age, especially significant after the age of 35. This effect is probably related to the biological degenerative processes of female fertility with age. A linear increase of birth intervals with birth order within families was found as well as a reduction of intervals among families experiencing an infant death. Our sample size was insufficient to detect a possible replacement behavior in the case of infant death. High natality and mortality rates, a secular decrease of natality rates, a log-normal birth interval, and family-size distributions suggest that La Alpujarra has been a natural fertility population following a demographic transition process.

Adult↗

PubMed1976

Birth order, maternal age and birth interval in epidemiology.

Foetal wastage and congenital malformations are not so closely associated with birth order, maternal age and birth interval as is suggested by data pooled across sibships of different sizes. The point could only have been established by data on large numbers of individual sibships. Maternal age, parity and birth interval are convenient but confusing variables to work with. However if they are to be used, it is essential to recognize that if the condition being studied may be associated with fertility of the parents, one needs to ascertain numbers of completed sibships containing affected cases. Incidence rates by age, parity and birth interval imply nothing by themselves.

Birth Order↗

PubMed2002

The impact of labor-saving technology on first birth intervals in rural Ethiopia.

Across the developing world labor-saving technologies introduce considerable savings in the time and energy that women allocate to work. Hormonal studies on natural fertility populations indicate that such a reduction in energetic expenditure (rather than improved nutritional status alone) can lead to increased ovarian function. Other qualitative studies have highlighted a link between labor-saving technology and behavioral changes affecting subsequent age at marriage, which may affect fertility. This biodemographic study was designed to investigate whether these physiological and behavioral changes affect fertility at a population level by focusing on a recent water development scheme in Southern Ethiopia. The demographic consequences of a reduction in women's workload following the installation of water points, specifically the variation in length of first birth interval (time lapsed between marriage and first birth), are investigated. First birth interval length is closely associated with lifetime fertility in populations that do not practice contraception, longer intervals being associated with lower fertility. Using life tables and multivariate hazard modeling techniques a number of significant predictors of first birth interval length are identified. Covariates such as age at marriage, season of marriage, village ecology, and access to improved water supply have significant effects on variation in first birth intervals. When entered into models as a time-varying covariate, access to a water tap stand is associated with an immediate reduction in length of first birth intervals.

Adolescent↗

PubMed1992

Interpreting demographic effects in duration analyses of first birth intervals.

"Estimated demographic effects in proportional hazard models of first birth intervals could reflect time-invariant differences in the risk of a birth, or differences in the timing of a shift in the risk, or both. This paper attempts to distinguish between these possibilities. The procedure is to estimate a more general model than the proportional hazard specification, in which the evolution of the risk of a birth can differ with demographic characteristics. The proportional hazard specification is nested within this more general model. Consequently, the consistency of the data with the 'risk' or the 'timing' interpretation of demographic effects can be tested. The data studied do not lead to a rejection of the proportional hazard specification." Data are from the 1984 U.S. National Longitudinal Survey Youth Cohort and concern 670 women aged 16 or 17 in 1979.

Americas↗

PubMed2006

The distribution of consecutive closed birth intervals in females in Uttar Pradesh.

Most studies of closed birth intervals are regarding their variation at specific orders among females. This paper attempts to study the nature of the distributions of consecutive closed birth intervals. Data from the Uttar Pradesh National Family Health Survey 1998-99 (NFHS-2) were analysed. It was found that, under certain assumptions, the postpartum amenorrhoea period and menstruating interval are negatively associated, indicating that socio-cultural factors are affecting the menstruating interval.

Amenorrhea↗

PubMed1997

The relation of closed birth intervals to the sex of the preceding child and the sexual orientation of the succeeding child.

The study investigated whether homosexual men are, on average, born a shorter time after their next-older siblings than are heterosexual men. Because of mixed evidence that birth intervals are longer after a male child, the sex of the next-older sibling was included as a control variable. The probands were 220 heterosexual and 183 homosexual men with at least one older sibling examined in Southern Ontario in 1994-95. These completed a self-administered, anonymous questionnaire concerning their family background and other biodemographic information. The results showed that birth interval was negatively correlated with sibship size, positively correlated with maternal age, and uncorrelated with paternal age. They also confirmed that birth intervals are longer after a male than after a female child. The mean birth intervals preceding heterosexual and homosexual males, however, were virtually identical, indicating that the association of short birth intervals with decreased sex hormone levels in cord blood is unrelated to the development of sexual orientation.

Adolescent↗