Maternal nutrition is important to a developing embryo and to the health of the child later in life. Supplementing the diet with specific vitamins is known to increase health of the foetus for example folic acid (vitamin B9) reduces the risk of spina bifida. However not everything an adult might consume is beneficial to a developing baby. New research published in BioMed Central's open access journal BMC Medicine shows that caffeine is linked to low birth weight babies and that caffeine from coffee in linked to increasing length of pregnancy.
Along with nutrients and oxygen, caffeine feely passes the placental barrier, but the developing embryo does not express the enzymes required to inactivate it efficiently. The WHO currently suggests a limit of 300mg 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.
To investigate the impact of maternal caffeine during pregnancy on babies, a research team from the Norwegian Institute for Public Health used information about mother's diet and birth details collected over ten years. 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.
Explaining their results, Dr Verena Sengpiel, from Sahlgrenska University Hospital, Sweden, who led the project said, "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."