Preterm Birth Among US and Foreign-Born Non-Hispanic Black Birthing Parents in Massachusetts: Variation by Nativity, Region, and Country of Origin.

Individual-level factors do not explain observed variation among NHB birthing parents. Future research should investigate explanations for lower PTB risk among SSAs, and congruent risk among foreign-born Caribbeans, Brazilians and US-born NHBs. Exposure to racism, a known risk factor for PTB, likely contributes to these inequities in PTB and merits further exploration. Prenatal care providers should assess place of birth among foreign-born NHBs, as well as exposure to racial discrimination among all NLB birthing parents.