Introduction: Reducing racial/ethnic disparities is a key objective of the Healthy People 2010 initiative. Unfortunately, racial disparities among women delaying initiation of childbearing have received limited attention. As more women in the US are delaying initiation of childbearing, it is important to examine racial disparities in reproductive health outcomes for this subgroup of women.
Objective: To examine racial disparities in perinatal outcomes, interpregnancy interval, and to assess the risk for adverse outcomes in subsequent pregnancy for women delaying initiation of childbearing until age 30 or older compared to those initiating childbearing at age 20-29.
Methods: We conducted a retrospective cohort study using the Missouri maternally linked cohort files 1978-1997. Final study sample included 239,930 singleton sibling pairs (Whites and African Americans). Outcome variables included first and second pregnancy outcomes (fetal death, low birth weight, preterm delivery and small-for-gestational age) and interpregnancy interval between first and second pregnancy. Independent variables included maternal age at first pregnancy and race. Analysis strategies used involved stratified analyses and multivariable unconditional logistic regression; interactions between maternal race, age and interpregnancy interval were examined in the regression models.
Results: Compared to Whites, African American mothers initiating childbearing at age 30 or older had significantly higher rates of adverse outcomes in the first and second pregnancy (P < 0.0001). Generally, African Americans had significantly higher rates of second pregnancy following intervals <6 months compared to Whites; however, no significant racial differences were noted in interpregnancy interval distribution pattern after controlling for maternal age at first pregnancy. African Americans delaying initiation of childbearing had significantly higher risk for adverse perinatal outcomes in the second pregnancy compared to Whites after controlling for potential confounders, however there were no significant interactions between maternal age at first pregnancy, race and short interpregnancy interval.
Conclusion: Although African Americans were less likely to delay initiation of childbearing than were White women, their risk for adverse perinatal outcomes was much greater. As health care providers strive to address racial disparities in birth outcomes, there is need to pay attention to this unique group of women as their population continues to increase.