Coffee consumption, birthweight, and reproductive failures.

We studied the effect of coffee consumption on birthweight, preterm births, and congenital malformations. From April 1985 to April 1987, 11,858 pregnant women out of 13,815 in two Danish cities responded to a mailed questionnaire on eating and drinking habits during pregnancy. Data on pregnancy outcomes were recorded from medical files. Maternal coffee consumption of four cups a day or more was associated with a moderate decrease in birthweight, especially among smokers. The associations between coffee consumption and preterm births or congenital malformations were very weak.