In this latest study, Prof Hui Wang and colleagues at Wuhan University in China investigated the effects of low (equivalent to 2-3 cups of coffee) and high doses (equivalent of 6-9 cups of coffee) caffeine, given to pregnant rats, on liver function and hormone levels of their offspring. 

Offspring exposed to prenatal caffeine had lower levels of the liver hormone, insulin-like growth factor (IGF-1), and higher levels of the stress hormone, corticosteroid at birth. However, liver development after birth showed a compensatory “catch-up” phase, characterized by increased levels of IGF-1, which is important for growth.

Dr. Yinxian Wen, the study co-author, says: “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 signaling decreases. 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,” adds Wen.