Prepregnancy Risk Factors for Preterm Birth in a Hispanic WIC Population

Despite improvements in prenatal healthcare, preterm birth remains the leading cause of infant mortality. The causes of preterm birth are not well-understood, especially in Hispanics—who nationally have preterm birth rates comparable to non-Hispanic whites despite socioeconomic disadvantages. Even less understood are the effects maternal nativity may have on the causes of preterm birth. This study aims to assess prepregnancy risk factors for preterm birth in a Hispanic population of WIC participants in Southern California, if prevalence of preterm birth differs by maternal nativity, and whether there is effect measure modification of any associations between risk factors and preterm birth by nativity on the multiplicative scale. Cross-sectional survey data (N = 1174) were collected within one year postpartum and assessed by logistic regression with sampling weights. After adjustment for confounders, risk factors for preterm birth were maternal age 35 or older, and stressful life events among U.S.-born but not foreign-born women. The prevalence of preterm birth in this low-income study population (15.1%) suggests the risk of preterm birth in Hispanic women may be low relative to non-Hispanic black women. Further investigation with large, prospective studies is needed to better understand the causes of and disparities in preterm birth among the growing Hispanic population in the U.S