A 15-year follow up study found that children born to mothers who drank caffeine-laden drinks during pregnancy were 89% more likely to be obese, compared to kids of moms who refrained.
The findings of Dr. De-Kun Li, a physician and researcher at Kaiser Foundation Research Institute and Stanford's school of medicine and colleagues showed that children born to mothers who consumed more than 150 milligrams of caffeine daily, equivalent to a medium-sized cup of coffee, were 2.3 times more likely to become obese.
The study included more than 600 mothers and children over a 15-year period. Data was collected from the women during pregnancy about their diet and caffeine intake, and then health records of their children were examined.
Caffeine affects the development of the part of the brain involved in metabolism. Also, caffeine easily passes the placental barrier between the blood of the mother and fetus but the substance affecting the fetus is unknown.
Animal studies show that caffeine can interfere with the ability to metabolize sugar, increases insulin resistance, which can lead to higher blood sugar levels.
Leonardo Trasande, a researcher at New York University's school of medicine said, "Further study is needed before doctors should consider changing this advisory, to consider other risks such as obesity." He suggests that "pregnant women should limit their consumption of caffeine" in the meantime.