The impact of prenatal care on preterm births among twin gestations in the United States, 1989-2000

OBJECTIVE: The purpose of this study was to determine the association between prenatal care and preterm births among twin gestations in the presence and absence of high-risk pregnancy conditions. STUDY DESIGN: Twin birth data in the United States were used to determine the association between preterm birth and prenatal care with the use of logistic regression. RESULTS: Of the 779,387 twin births, 54.7% twin births were delivered preterm. The rate was higher among black women than among white women in the presence (57.0% vs 51.2%, respectively) and absence (70.3% vs 61.6%, respectively) of prenatal care. The absence of prenatal care increased the relative risk for preterm birth by 1.24-fold among black women and by 1.22-fold among white women. Lack of prenatal care was associated with increased preterm birth rates in the presence of most high-risk conditions. CONCLUSION: Prenatal care is associated with fewer twin preterm births in the presence and absence of high-risk conditions. Increased prenatal care participation may help decrease preterm birth rates and also narrow the black-white twin preterm birth disparity.