Alcohol consumption and serum hormone levels during pregnancy

Factors that change sex hormone levels during pregnancy may have long-term health consequences for the offspring, including changes in breast cancer risk. A cross-sectional analysis of alcohol consumption and hormone levels in 339 pregnant women sampled from the Child Health and Development Study cohort was undertaken. Alcohol intake was queried from 1959 to 1966, long before any hazards of drinking during pregnancy were publicized. Third trimester serum hormone levels including estradiol and testosterone were analyzed. Among 339 pregnant women, 196 reported some alcohol consumption during pregnancy. The drinkers were divided into three groups with intake levels of 0.2-0.5, 0.6-2.0, and 2.1-12.5 ounces of ethanol per week. The second group corresponds to a median intake of approximately 2 drinks per week, and the last group corresponds to a median intake of approximately 1 drink per day, which is considered "light" to "moderate" drinking. Maternal estradiol levels were not associated with alcohol intake during pregnancy. However, serum testosterone was significantly lower, by 12.2%, in the latter two groups of drinking pregnant women, [confidence interval (CI)=-3.0 to 25.2] and 25.6% (CI=9.2-39.5), respectively. The alcohol intakes reported are far below those shown to cause fetal alcohol syndrome, or any of the fetal alcohol effects so far studied. Light alcohol intake during pregnancy is associated with lower maternal testosterone. The health implications are uncertain, but may include an increased breast density in the daughters of drinking mothers.