It’s about Time: Data on Interpregnancy Interval Using the National Survey of Family Growth and the National Vital Statistics System

Casey E. Copen, National Center for Health Statistics (NCHS), CDC
Marie Thoma, National Center for Health Statistics (NCHS), CDC
Sharon W. Kirmeyer, National Center for Health Statistics (NCHS), CDC

Research shows a relationship between short interpregnanacy intervals (IPI) (< 18 months) and reproductive risk; however, the correlates of longer IPI (60 or more months) have not been examined. Data from the National Survey of Family Growth (NSFG) were used to examine the association between maternal characteristics and IPI among a nationally representative sample of 12,279 women. Adjusting for sociodemographic and childbearing characteristics, short IPI were more likely among women who were younger, married, women with 2 or more prior live births and who reported the pregnancy as unintended. In the adjusted models, Hispanic and non-Hispanic black women had longer IPI than non-Hispanic white women, though we had limited power to detect differences. In the final paper, data from the 2011 birth certificate (revised in 2003 to include date of last live birth) will be compared to the NSFG to provide a more comprehensive picture of IPI in the U.S.