Effect of the interpregnancy interval on perinatal outcomes in Latin America

Objective: To estimate whether interpregnancy interval is independently associated with increased risk of perinatal death and other adverse perinatal outcomes. Methods: We investigated the effect of interpregnancy interval on perinatal outcomes in 1,125,430 pregnancies recorded in the Perinatal Information System database of the Latin American Center for Perinatology and Human Development, Montevideo, Uruguay, between 1985 and 2004. Odds ratios (ORs) were adjusted for 16 major confounding factors using multiple logistic regression models. Results: Compared with infants with interpregnancy intervals of 18-23 months, those born to women with intervals shorter than 6 months had an increased risk of early neonatal death (adjusted OR 1.49, 95% confidence interval [CI] 1.06-1.96), fetal death (adjusted OR 1.54, 95% CI 1.28-1.83), low birth weight (adjusted OR 1.88, 95% CI 1.78-1.90), very low birth weight (adjusted OR 2.01, 95% CI 1.73-2.31), preterm birth (adjusted OR 1.80, 95% CI 1.71-1.89), very preterm birth (adjusted OR 1.95, 95% CI 1.67-2.26), and small for gestational age (adjusted OR 1.30, 95% CI 1.25-1.36). Intervals of 6-11 months and 60 months and longer were also associated with a significantly greater risk for the 7 adverse perinatal outcomes. Conclusion: In Latin America, interpregnancy intervals shorter than 12 months and longer than 59 months are independently associated with increased risk of adverse perinatal outcomes. These data suggest that spacing pregnancies appropriately could prevent perinatal deaths and other adverse perinatal outcomes in the developing world.