Effects of caffeine consumption on pregnancy outcome. A review.

Caffeine's metabolism, mechanisms of action and effects on pregnancy outcome in laboratory animals and humans have been studied extensively. A review of those studies suggests that until more information is available, it might be prudent to limit caffeine intake to approximately 300 mg/d during pregnancy in view of decreases in birth weight that might occur at or above that level of consumption. That level might also be appropriate for nursing mothers since caffeine is known to enter breast milk.