Scientists from Ireland yesterday said consuming caffeine during pregnancy may be bad for the health of the unborn baby. Findings of a study published in ‘The American Journal of Clinical Nutrition,’ showed a consistent link between caffeine sourced from coffee and tea and adverse birth outcomes. According to the researchers, regardless of the caffeine source, whether from tea or coffee, the risks of delivering babies with abnormally low birth weight or short gestational age at birth were higher. Apart from smaller birth size and shorter gestational duration, maternal caffeine intake had been linked to other negative outcomes for the child, such as a lower intelligent quotient (IQ). However, these findings, including that of the current study, were from observational studies. The team said observational studies cannot prove that caffeine causes these outcomes, only that there was a link between them. To prove causation, scientists would need to conduct randomized, controlled trials, they stated.
The researchers said until more definitive evidence emerges, it was prudent to at least limit caffeine intake during pregnancy or when planning to conceive. The team wanted to know if there was a link between maternal caffeine intake and negative birth outcomes in a population where tea was the main caffeine source. Consequently, they used data from an Irish cohort study involving about 1,000 Irish women that provided the researchers with the usual dietary intakes of caffeinated products during early pregnancy. We matched these with hospital records of the women’s newborns to get information on the birth size and gestational age at birth.
Tea was the predominant caffeine source (48 per cent), followed by coffee (39 per cent). “In the highest caffeine consumption group, the risks of delivering babies with abnormally low birth weight or short gestational age at birth were about two times higher. The results were similar regardless of the caffeine source,” the researchers disclosed. Caffeine is the most commonly used psychoactive substance in the world. And at average consumption levels, it is considered to be good for health, or at least not bad for health. While coffee is the main source of caffeine in most parts of the world (about 100mg per cup), it is less recognised that tea contains a significant amount of caffeine, too (about 33mg per cup).
“Brewing methods and types of coffee and tea influence their caffeine contents. For example, caffeine content is higher in brewed coffee than in instant coffee, and it’s higher in black tea than in green tea. “So, our findings have potentially important public health implications in countries where a lot of black tea is consumed, such as Ireland and the United Kingdom (UK).”