Abbreviations: uOR, unadjusted odds ratios; aOR, adjusted odds ratio; CI, confidence interval; *Adjusted Odds ratios and CIs were reported using unconditional logistic regression after adjusting for maternal age, the time elapsed since index pregnancy, education level, gravida, smoking status, bleeding at first trimester, health insurance status.

_{Data are expressed as binary variables and as n (column
%); n = proportion of individuals with outcomes in each racial
category.}