Effect of the Interval Between Pregnancies on Perinatal Outcomes Among White and Black Women

Objective: We evaluated interpregnancy interval in relation to adverse perinatal outcomes and whether the relationship differed by race.

Study Design: We analyzed the vital statistics data for multiparous white and black women in Michigan who delivered a singleton live birth during the period 1993 through 1998, using stratified and logistic regression techniques.

Results: Among women of both races, the risk for delivering low birth weight, premature, and small-for-gestational-age birth was lowest if the interpregnancy interval was 18 to 23 months. In comparison, among white women, the odds ratios for the 3 outcomes were 1.5, 1.3, and 1.3, respectively, if the interval was <6 months, and 1.9, 1.4, and 1.7, respectively, if the interval was > or =120 months, controlling for other factors. Similarly, among black women, the odds ratios were 1.5, 1.2, and 1.3, respectively, if the interval was <6 months, and 1.6, 1.3, and 1.4, respectively, if the interval was > or =120 months.

Conclusion: An interpregnancy interval of 18 to 23 months is associated with the lowest risk for adverse perinatal outcomes among both white and black women.