Watch out for those cups of coffee, expecting mothers! Recent studies have established a link between the amount of caffeine intake during pregnancy and adverse birth outcomes.
Previous works have focused on coffee particularly and shown that the mother's coffee intake can lead to negative effects on the foetus. The latest study, published in the American Journal of Clinical Nutrition, shifts the inquiry to the intake of tea as the predominant source of caffeine and shows similar results.
The Study
Data was collected from 941 Irish mother-child pairs of the Lifeways Cross Generation Cohor Study by assessing the dietary intakes in early pregnancy through questionnaires. Caffeine intake was derived from coffee, tea, soft drinks and cocoa-containing foods and beverages. Tea remained the predominant caffeine source (48%) followed by coffee (39%).
The study revealed that maternal caffeine intake was associated with lower birth weight, shorter birth length, smaller head circumference and shorter gestational age. Women who took in the most caffeine had babies weighing about 170 grams (6 ounces) less than those who consumed the least.
Lead study author Ling-Wei Chen, a researcher at University College Dublin in Ireland, recommended pregnant women to restrict their caffeine intake. He explained,
High caffeine intake can result in restricted blood flow in the placenta which may subsequently affect foetal growth. Caffeine can also cross the placenta readily,and because caffeine clearance slows as pregnancy progresses, caffeine accumulation may occur in foetal tissues.
The study points towards the importance of recognizing the caffeine content in tea and advises companies selling tea or coffee to include a caveat stating their possible ill-effects.
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