Pregnant women who drink one to two cups of coffee a day do not risk harming their children’s intelligence or increasing the risk of behavioral problems, according to a new study.
Researchers at the Nationwide Children’s Hospital in Columbus, Ohio looked for markers of caffeine in the bloodstream of expectant mothers at two different points during pregnancy. After comparing those levels to children’s IQ and behavior at four and seven years of age, they found no consistent pattern between higher caffeine intake and behavioral problems or lower IQ.
One of the difficulties in studying the effects of caffeine on pregnant women is that because we know there are risks at high levels of intake, it is hard to attract people to participate in any research. The Nationwide study looked at 2,197 mother-child pairs in the US between 1959 and 1974, when caffeine had not been flagged as a major risk and intake was far higher than it is today.
The advice pregnant women get on caffeine can be confusing. My doctor told me to cut out caffeine completely and I, blindly, followed her instructions because I was old and did not want to take any additional risks. But other pregnant women I knew— most notably those who already had children—drank coffee without worry. (I would later appreciate how important this is; when you have a toddler and you are pregnant, you sleep horribly and desperately need caffeine.)
The US government, in its 2015 dietary requirements, notes that (pdf) very little research has been done in this area. It concludes that moderate caffeine consumption is not associated with higher risks of pre-term delivery, but that higher caffeine consumption is associated with a small increased risk of miscarriage, stillbirth, and low birth weight.
It says more research is needed and defers to the American Congress of Obstetricians and Gynecologists, which recommends no more than 200mg of caffeine per day (approximately two cups of coffee).
A doctor friend of mine was also swayed in her first pregnancy (no booze, no caffeine), muted in her second (one cup of coffee a day and one glass of wine a week) and dismissive with her third (two cups of coffee a day, a glass of wine when needed). She swears her third kid is the smartest of the lot.