Recurrence of early preterm, late preterm, and early term birth by race/ethnicity and insurance status

Publication Date


Document Type


Publication Title

American Journal of Obstetrics and Gynecology




1, Supplement



First Page



To examine racial/ethnic and socioeconomic differences in recurrence of preterm birth (PTB) and early term birth among women in California.

Study Design
We included linked data from birth certificates and hospital discharge summaries from first and second singleton births between 22 and 42 weeks’ gestation among non-Hispanic Black, non-Hispanic White, Hispanic, and Asian women from 2007-2012. Insurance type for each pregnancy was classified as “Medicaid” or “other”. We used logistic regression to compare the odds of recurrence of any PTB (<37 weeks), early PTB (<32 weeks), late PTB (32-36 weeks), and early term birth (37-38 weeks), stratified by race/ethnicity and by insurance type. We adjusted for maternal characteristics and obstetric risk factors in each pregnancy.

The sample (N=253,514) included 5.3% Black, 40.7% White, 36.8% Hispanic, and 17.3% Asian women. Compared to White women, Black, Hispanic, and Asian women with a PTB in the first pregnancy had a higher prevalence of recurrence of any PTB (11.2%,7.5% and 7.5%, respectively, compared to 3.9%), early PTB (10.8%, 10.2%, 9.1% compared to 7.4%), late PTB (18.5%, 18.0%, and 18.1% compared to 17.4%) and early term birth (37.2%, 37.6%, 43.2% compared to 36.2%). Women who had Medicaid coverage for both pregnancies had higher PTB recurrence rates than women who had another insurer (7.7% compared to 6.0%). In adjusted models, any PTB, early PTB, late PTB, and early term births in the first pregnancy were associated with increased odds of shorter gestational length in the second pregnancy, regardless of racial/ethnicity and insurance type. White women with a prior early PTB had the highest odds of a subsequent early PTB (OR 54.0; 95% CI 37.0, 78.9). The odds of recurrent early PTB were also strongly associated with prior early PTB for Black (OR 26.3; 95% CI 15.4, 45.0), Hispanic (OR 45.8, 95% CI 33.8-60.0), and Asian women (34.1 95% CI 19.7, 58.9). Any PTB in the first pregnancy was associated with recurrence for women who had Medicaid coverage for both pregnancies (OR 12.1, 95% CI 9.6, 15.2) as well as for those who had other insurance (OR 14.21, 95% CI 11.8, 17.2).

Prior PTB and early term birth increased the odds of PTB recurrence, across all races/ethnicities and insurance types. Despite Black women experiencing higher prevalence for each category of PTB recurrence, prior birth outcome was most strongly associated with recurrence among White women.


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