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SummaryMost studies on birth intervals and infant mortality ignore pregnancies that do not result in live births. Yet, fetal deaths are important in infant mortality analyses for three reasons: ignoring fetal deaths between two live births lengthens the measured interval between births, implying that short intervals are underestimated; the recommended inter-pregnancy interval (IPI) after a fetal loss is shorter (6 months) than after a live birth (24 months), as the effect of IPI on outcomes might differ according to the previous type of pregnancy outcome; fetal death will selectively reduce the population at risk of neonatal mortality, leading to biased results. This study uses the Heckman selection model to simultaneously estimate the combined effect of IPI duration and the type of pregnancy outcome at the start of the interval on pregnancy survival and neonatal mortality. The analysis is based on retrospective data from the Rwanda Demographic Health Surveys of 2000, 2005 and 2010. The results show a significant selection effect. After controlling for the selection bias, short (60 months) intervals after a fetal death reduce the chances of pregnancy survival, but no longer have an effect on neonatal mortality. For intervals starting with a live birth, the reverse is true. Short intervals (

This paper examines the association between infant mortality of the first born and subsequent children using data from rural Bangladesh collected during the period 1971-82. It shows that birth spacing and age of mother at the time of the second birth are important predictors of the survival status of the first child. The findings are discussed in terms of policy implications.This study examines the mortality of the first born and the death of a subsequent child in Bangladesh. Data are obtained from the Demographic Surveillance System of the International Center for Diarrheal Disease Research during 1974-82. The sample includes 1772 mothers who had first births and 1032 who had second births. 245 first-born and 159 second-born infants died. 740 mothers of first-born infants did not have a second child. 176 women had signs of secondary infertility. Bivariate analysis of the correspondence between first mortality status and age at death of the second child indicates an inverse relationship. The probabilities of neonatal or infant death among second children were highest among mothers whose first child also died neonatally. The second-birth mortality risk was consistently higher for all mortality among first births up to 1 year of age and lower if the first birth survived the neonatal stage. Risk was higher among mothers aged under 20 years and if the second child was a male. If the first child was a male, the probability of the second child surviving was higher. The hazard model analysis reveals that birth spacing was an important determinant. Shorter birth interval between first and second births was related to a higher relative risk of dying among first births. The analysis suggests that birth spacing and maternal age at the time of the second birth were important factors relating to the survival status of the second child. The implication of the findings is that biological variables, such as birth weight, may offer a better explanation for the association between socioeconomic and demographic factors and infant mortality. Health interventions, such as child care and nutrition education, may be more effective in reducing the risk of subsequent mortality.

The 1988 Malawi Traditional and Modern Methods of Child Spacing Survey data are used to identify determinants of infant mortality in Malawi. The logistic binomial analysis shows that socioeconomic factors are significant even during the neonatal period while the length of the preceding birth interval is significant in the post-neonatal period only. There is a strong familial correlation of mortality risks during both the neonatal and post-neonatal periods but the effect of geographical area of residence is stronger in the post-neonatal period.Two logistic binomial models for neonatal mortality (under 1 month) and post-neonatal mortality were used to determine the probability of dying among families in Malawi. Data was obtained from 3043 women aged 15-54 years on 6258 births, which occurred 0-15 years before the survey, from the 1988 Malawi Traditional and Modern Methods of Child Spacing Survey. Mortality included 211 post-neonatal deaths, 147 toddler deaths, and 172 child deaths. Missing information or date of death missing information pertained to 182 reported deaths that were excluded from the analysis. Logistic models were run with the complete sample and the sub-sample and found to have similar results. Findings showed that children born in homes with electricity had 34% lower risk of dying than children born in homes without electricity. Preceding birth interval was unrelated to neonatal mortality. Neonatal mortality rates were significantly higher in Chiradzulu rural area, which was found to have a lower proportion of mothers with five or more years of education. The random term, which was high, suggested a high familial correlation with neonatal mortality risk. Findings showed that families with favorable characteristics living in the Chiradzulu area had a probability of 0.005 of a neonatal death. Low risk families in unfavorable circumstances had lower probabilities of child loss than high risk families with favorable conditions. Significant determinants of post-neonatal mortality were preceding birth interval, maternal education, father's occupation, and geographic area. Women with 9 or more years of education had lower infant mortality risks. Family effects were significant, even after controlling for socioeconomic conditions. The most favorable conditions for child survival were: no preceding child; a preceding birth interval of 19 months or longer; maternal education of 9 or more years; and paternal employment in non-manual work.

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.Child spacing patterns have been found to be reflected in the interaction between a variety of biological and social factors in India. Birth intervals differ from Western patterns: long lengths of postpartum amenorrhea and prolonged breast feeding. Cox proportional hazards models and descriptive statistics are used to examine birth intervals among 3514 households in the Varanasi district of Uttar Pradesh state in 1978, and among 3000 households from 3 districts in Kerala state in 1980. Women using contraception or who were sterilized were excluded from the analysis. Birth spacing among Urrar Pradesh women was 44 months from marriage to first birth and 32 months between subsequent births. In Kerala, the first birth interval was 20 months and subsequent intervals were up to 30 months. In Uttar Pradesh, the median birth interval declined as age at marriage increased; in the sample populations, age-at-marriage groups differed widely in their birth intervals. Birth intervals also varied with household economic status. Based on the social status index and educational status of husband and wife in Uttar Pradesh, differences in median birth intervals were minimal but large for the extent of childbearing. 28% of higher class women had a 5th child compared to 2% among low status groups. When controlling for marriage age and other variables, the proportional hazards model showed that all groups, other than the high status group, had a statistically significant higher risk of a birth. When using education as the status measure in Kerala, the findings on birth interval were similar, but the proportion having a 2nd birth was higher among lower status groups. Husband's education did not have much effect on birth interval. Religion did not strongly affect the risk of birth other than for first births in Uttar Pradesh. In Kerala, there were shorter birth intervals among Muslims and a higher probability of parity progression to the next birth. Muslims and Christians versus Hindus had a significantly higher adjusted risk of birth. Infant mortality shortened birth intervals for women in Uttar Pradesh by 9 months, and the adjusted risk of a next birth was 2 times higher. Kerala results were similar, but replacement was less likely with higher order births. Both states had slightly longer birth intervals after a male child.