Caffeine is a stimulant found in tea, coffee, cola, chocolate and some over-the-counter medicines. Conflicting results found in the literature make it difficult for health professionals to advise pregnant women about avoiding caffeine during pregnancy. Clearance of caffeine from the mother's blood slows down during pregnancy. Some authors of observational studies have concluded that caffeine intake is harmful to the fetus, causing growth restriction, reduced birthweight, preterm birth or stillbirth. The newborn could also have withdrawal symptoms if the mother has a high intake of caffeine (more than eight cups of coffee per day).
Two studies met the inclusion criteria but only one contributed data to the outcomes of interest. The study was based in Denmark. Women less than 20 weeks pregnant were randomly assigned to drinking caffeinated instant coffee (568 women after exclusions) or decaffeinated instant coffee (629 women). Drinking three cups of coffee a day in early pregnancy had no effect on birthweight, preterm births or growth restriction.
Sufficient evidence is not available from randomised controlled trials to support any benefits from avoiding caffeine during pregnancy.