Until recently a large body of research conducted in high-income countries had unambiguously shown that children born after very short birth intervals are at an elevated risk of poor perinatal outcomes. However, a handful of recent studies using sibling fixed effects have cast doubt on that conclusion. We use Swedish population data on cohorts born 1981-2010 and sibling fixed effects models to examine whether the length of the birth interval preceding the index person has an impact on the risk of preterm birth, low birth weight, and hospitalization during childhood. For the first time for this particular research question we also present analyses stratified by salient social characteristics such as maternal educational level, and maternal country of origin. We find few effects of birth intervals on our outcomes except for very short birth intervals. We also find few differences in the patterns by maternal educational level, or country of origin.
Presented in Session 5. Health & Mortality 1