[Interaction of prenatal care and level of maternal education on the risk of neonatal low birth weight].

To investigate the interaction of prenatal care indexes including weeks of initiation of prenatal care, number of prenatal care visits and maternal educational level on the risk of neonatal low birth weight (LBW).Logistic Regression Model was performed to estimate the association including the interaction with OR and 95%CI between prenatal care indexes and LBW risk in all the subjects. Three educational levels(junior high, senior high, junior college) of mothers were also assessed. New variables of the prenatal care indexes were transformed using the quartiles, according to the distribution of the original variables on pregnant women with newborns of normal birth weight.Whether the pregnant women were stratified by educational level, with the increasing number of prenatal care visits, LBW risk was shown a U-type tendency in different strata of educational levels, when comparing with the reference group, respectively. Compared to the baseline group, the OR and 95% CI of the third quartile on number of prenatal care visits were 0.48 (0.35-0.64), 0.55 (0.32-0.95), 0.50 (0.32-0.80), 0.36(0.20-0.66) in all subjects who had received educational levels as junior middle school, senior middle school or junior college degree ect., respectively. A significant interaction was shown between the number of prenatal care visits and maternal educational level on the neonatal LBW risk (χ² = 4.650 2, P = 0.031 1). However, no interaction was found between the week of initiation of prenatal care and maternal educational level on the neonatal LBW risk (χ² = 0.929 7, P = 0.334 9).Data from our study indicated that there was a protective interaction on reducing the neonatal LBW risk between maternal educational level and the number of prenatal care visits, but not the weeks on the initiation of prenatal care. More prenatal care programs should be implemented among the pregnant women with lower educational level.