Patterns of alcohol use before and during pregnancy and the risk of small-for-gestational-age birth.

Few studies have examined the effect of binge drinking on human fetal growth. The authors studied the effect of binge drinking 3 months before pregnancy and during the last 3 months of pregnancy on small-for-gestational-age (SGA) birth, using data from the Pregnancy Risk Assessment Monitoring System (PRAMS). PRAMS is an ongoing US survey of women who recently delivered a liveborn infant. Data are collected 2-6 months after birth by using mailed, self-administered questionnaires, with telephone interviews conducted for nonresponders. This study included 50,461 women who delivered at term from 1996 to 1999. Overall, binge drinkers before pregnancy were less likely than nondrinkers to have an SGA birth, but moderate or heavy drinkers (>or=4 drinks per week) who also binged were 2.2 times more likely to have an SGA birth. Moderate and heavy drinkers in late pregnancy were also more likely to have an SGA birth, but there were only 46 women in these categories, so estimates were imprecise. Vascular effects of alcohol or dietary differences between drinkers and nondrinkers may explain the lower risk of SGA birth among some drinkers. The relation of these areas with fetal growth needs more research.