The negative relationship between birth interval length and neonatal mortality risks is welldocumented,
but the possibility of heterogeneity in this relationship has been largely ignored.
Understanding variation in the strength of this relationship may be important for adjusting family
planning programs strategies for issues regarding fertility regulation and maternal and child health,
however, as donor support of these programs has been declining in recent decades (Cleland et al.,
2006). Using the Bangladesh Maternal Mortality and Health Care Survey 2010, this study
investigates how the effect of birth interval length on neonatal mortality risks varies along three
dimensions: birth cohort, maternal age at birth, and maternal education. The results show that the
average effect of interval length on mortality has approached zero across birth cohorts, but that
significant variation exists with respect to maternal age and education. Young women and those
with little education, both of which make up a large share of the Bangladeshi population, can
disproportionately benefit from increasing spacing between births.