A recent observational study published by BMJ Open suggests that mums-to-be should cut out caffeine while pregnant, as the findings show that it is linked to excess weight gain during the child’s early years. It passes rapidly through tissues, including the placenta, and takes the body longer to dispose of during pregnancy.
The study included almost 51,000 mother and infant pairs, all of whom were previously involved in the Norwegian Mother and Child Cohort Study between 2002 and 2008. Using a specifically adapted Food Frequency Questionnaire, the pregnant women were asked to quantify their food and drink intake, from around 255 items, including caffeine. Highly caffeinated items included things like coffee, black tea, energy drinks and various sugary snacks.
After the babies were born, their weight, height and body length were measured on 11 different occasions; first at 6 weeks old; then at 3, 6, 8, and 12 months; and finally, at 1.5, 2, 3, 5, 7 and 8 years old. The results of the study indicate that those children exposed to very high levels of caffeine whilst in the womb weighed more throughout the entirety of their first 8 years of life than those children exposed to low levels.
Observational studies can’t confirm causality or other external factors, but current advice already suggests that women should avoid caffeine during pregnancy as it has long been associated with a heightened risk of miscarriage and restricts the development of the foetus. The results of this study indicate that complete avoidance might be wise.