Caffeine Linked to Low Birth Weight Babies

Maternal nutrition is very important to a developing embryon and to the health of the child later in life. Supplementing the diet with specific vitamins is known to increase health of the foetus. However, not everything an adult might consume is beneficial to a developing baby. New research published in BioMed Central's open access journal BMC Medicines shows that caffeine is linked to low birth weight babies and that caffeine from coffee is linked to increasing length of pregnancy.

The World Health Organization (WHO) currently suggests a limit of 300 mg per day during pregnancy, but some countries recommend a limit of 200mg, which can be less than a single cup of coffee from some high street cafes. A research team from the Norwegian Institute for Public Health used information about mother's diet and birth details collected over 10 years was completed to investigate the impact of maternal caffeine during pregnancy on babies. After excluding women with medical and pregnancy-related conditions, almost 60,000 pregnancies were included in the study.

All sources of caffeine were monitored in the study: Coffee, tea, fizzy drinks, as well as food including cocoa-containing cakes and deserts and chocolate.

Dr. Verena Sengpiel, from Sahlgrenska University Hospital, Sweden, who led the project said the following regarding the study:"Although caffeine consumption is strongly correlated with smoking which is known to increase the risk for both preterm delivery and the baby being small for gestational age at birth (SGA). In this study we found no association between either total caffeine or coffee caffeine and preterm delivery but we did find an association between caffeine and SGA. This association remained even when we looked only at non-smoking mothers which implies that the caffeine itself is also having an effect on birth weight."

They found that caffeine from all sources reduced birth weight. For a child of expected average weight (3.6kg) this equates to 21-28g lost per 100mg caffeine per day. But it was not just caffeine, but the source of caffeine, which affected pregnancy outcomes. Caffeine from all sources increased the length of the pregnancy by 5 hours per 100mg caffeine per day, but caffeine intake from coffee was associated with an even longer gestational length - 8 hours extra for every 100mg caffeine per day.