Researchers have found that excess caffeine intake during pregnancy may impair baby's liver development and increase the risk of liver disease in adulthood.

In a study on rats, it was found that pregnant rats, which were given caffeine, had offspring with lower birth weight, altered growth and stress hormone levels and impaired liver development. Published in the Journal of Endocrinology, the study indicates that consuming 2-3 cups of coffee a day may alter stress and growth hormone levels in a manner that can impair development of baby's liver.

"Our results indicate that prenatal caffeine causes an excess of stress hormone activity in the mother, which inhibits IGF-1 activity for liver development before birth. However, compensatory mechanisms do occur after birth to accelerate growth and restore normal liver function as IGF-1 activity increases and stress hormone signalling decreases," said study co-author Yinxian Wen from the Wuhan University in China.

Insulin-like growth factor 1 (IGF-1) is a hormone that plays an important role in childhood growth. "The increased risk of fatty liver disease, caused by prenatal caffeine exposure, is most likely a consequence of this enhanced, compensatory postnatal IGF-1 activity," Wen said. For the study, the researchers investigated the effects of low (equivalent to 2-3 cups of coffee) and high doses (equivalent to 6-9 cups of coffee) of caffeine given to pregnant rats, on liver function and hormone levels of their offspring.

"Our work suggests that prenatal caffeine is not good for babies and although these findings still need to be confirmed in people, I would recommend that women avoid caffeine during pregnancy," Wen said. Sweta Gupta, Clinical Director and Senior Consultant at Fertility Solutions, Medicover Fertility in Delhi, agreed that too much of caffeine could be harmful for the baby. "Pregnancy is a time of craving and mood swings. Some consider coffee for relief in such situations," she said.

However, according to Harshal Rajekar, Consultant Gastro Surgeon, Columbia Asia Hospital in Pune, there is hardly any evidence showing that caffeine is harmful for pregnant woman or her baby's liver though it's true that excess of caffeine can affect sleep and may deprive the mother of adequate rest during pregnancy, which can, in turn, harm both the mother and the child.