This study examines whether mortality of two adjacent siblings in families is age-specific and is modified by the MCH–FP programme and fertility and mortality declines in Matlab, Bangladesh, using data for singleton births during 1977–78, 1985–86 and 1989–90 in the treatment (MCH–FP) and comparison areas. Logistic regression was used to estimate the net effects of survival status of elder siblings on mortality of younger siblings in the neonatal, postneonatal and toddler periods, controlling for birth order, previous birth interval, maternal age, education and religion, household possession of valuable items and sex of the child.

Odds of neonatal and postneonatal deaths of younger siblings were found to be higher if the elder sibling had died at the same age than if the sibling had survived infancy. Toddler mortality was lower if the elder sibling had died in infancy. The association between two siblings' mortality risks did not decline over time in either area. The results suggest that a family history of child deaths by age is important to identify when subsequent infants would be at a higher risk of dying.