Coffee is the most consumed beverage worldwide, with an average daily intake of >400 mg of caffeine, equivalent to approximately four cups, per capita in many European countries, such as Norway, Sweden, and Netherlands.
It has been estimated that ∼70% of pregnant women in the USA consume caffeine during pregnancy, with coffee being the main source of caffeine.
Coffee consumption has been associated with several adverse pregnancy outcomes. However, there is not much data from randomized-controlled trials.
Due to the physiological changes of pregnancy, there is a decreased rate at which caffeine is metabolized, especially during the third trimester, due to a decreased activity of the liver enzyme CYP1A. Because of this, caffeine can accumulate in the body throughout the pregnancy, with its half-life increasing from 3 h in non-pregnant women to ≤18 h for pregnant women at the end of pregnancy, and caffeine can freely cross the placenta.
Currently, the World Health Organization recommends a caffeine intake of <300 mg/day during pregnancy.
“Moderate coffee consumption appears to be safe during pregnancy”
Recently, a group of researchers published a study in the International Journal of Epidemiology, in which they found that drinking coffee during pregnancy likely does not contribute to any poor pregnancy outcomes.
For the study, the team used data from the Coffee and Caffeine Genetics Consortium, a meta-analysis of coffee consumption that includes 91,462 participants. In that study, information such as self-reported miscarriage, stillbirths, gestational age and pre-term birth, and birthweight was obtained.
The researchers found no change in the risk of sporadic miscarriages, stillbirths, pre-term birth, or effect on gestational age connected to coffee consumption.
The study has some limitations, such as not looking for specific developmental factors, like neurodevelopmental or organ development, which needs further research. However, the study did add to the growing evidence that suggests that pregnant women shouldn’t worry about moderate coffee consumption.
Caroline Brito Nunes, et al. Mendelian randomization study of maternal coffee consumption and its influence on birthweight, stillbirth, miscarriage, gestational age and pre-term birth, International Journal of Epidemiology, 2022;, dyac121, https://doi.org/10.1093/ije/dyac121