Alcohol consumption during pregnancy and birth outcomes: the Kyushu Okinawa Maternal and Child Health Study

BACKGROUND: A recent meta-analysis showed no relationships between light to moderate alcohol consumption during pregnancy and the risk of low birth weight (LBW), preterm birth (PTB), or small-for-gestational-age (SGA). Here, we present the first epidemiological study on this topic in Japan. METHODS: Study subjects were 1565 Japanese mothers with singleton pregnancies and the babies born from these pregnancies. Alcohol consumption during pregnancy was assessed using a self-administered diet history questionnaire. Alcohol consumption during pregnancy was classified into three categories (none, < 1 g/day, and ≥ 1 g/day). RESULTS: The mean birth weight of the babies was 3006.3 g. 7.7% were classified as LBW, 4.0% as PTB, and 7.8% as SGA. The range of maternal alcohol consumption during pregnancy was 0.0 to 11.7 g per day: 1356 (86.7%) mothers were abstainers and the 95th percentile value was 0.84 g per day. Compared with abstinence, alcohol consumption of 1.0 g or more per day during pregnancy was significantly associated with an increased risk of PTB with a significant positive linear trend: the adjusted OR for PTB associated with maternal alcohol consumption of 1.0 g or more per day was 2.58 (95% CI: 1.004 - 5.80, P for trend = 0.03). No significant relationships were observed between maternal alcohol consumption during pregnancy and the risk of LBW or SGA, and there was no material association between maternal alcohol consumption during pregnancy and birth weight. CONCLUSIONS: This is the first study in Japan to show that maternal alcohol consumption during pregnancy of 1.0 g or more per day was significantly positively associated with the risk of PTB, but not LBW or SGA.