For as long as I can remember, one of my very favorite things was sitting down in the morning with a hot cup of coffee. I’m not much of a chocolate eater or tea and soda drinker, so my caffeine throughout the day has always come from coffee.
After becoming pregnant, it was important to me to understand how coffee could affect my baby, what the current guidelines were, and what the research actually says about caffeine intake during pregnancy.
Let’s take a look.
Caffeine is a drug that stimulates your brain and nervous system. Studies show that about 85% of the US population consumes at least one caffeinated beverage per day, the majority of which comes from coffee (1).
In pregnancy, caffeine crosses the placenta, exposing the fetus to concentrations similar to systemic levels in the mom (2). Research has also linked high caffeine intake to increased levels of miscarriage (3, 4), preterm birth (3, 4) and low birth rate (5).
But when it comes to caffeine intake during pregnancy, the research, unfortunately, is not conclusive and is limited by small sample size, confounding factors that don't allow us to assess causality, and retrospective collection of data influenced by recall bias (6, 7, 8).
A meta-analysis of 53 studies aimed at investigating associations between caffeine intake and spontaneous abortion, stillbirth, preterm delivery, low birth weight and small for gestational age infants concluded that there was insufficient evidence to change current recommendations of 200mg/d in pregnancy (9). In 2020, a review article, which got a lot of press, looked at 48 studies or meta-analyses on caffeine intake and miscarriage, stillbirth, low birth weight and/or small for gestational age, preterm birth and concluded that no amount of caffeine in pregnancy was safe (5). However the review presented no new evidence - only discussed the evidence that already existed, which was used when making current guidelines for pregnant women. And a large majority of the papers reviewed did not control for confounders such as smoking, maternal age, and alcohol use, which are all associated with higher caffeine intakes and can lead to increased risk of miscarriage as well. With everything taken into account, the conclusion is certainly overstated and guidelines have not changed because of it.
What is much more clear is that caffeine intake amounting to about 200mg per day is almost certainly safe during pregnancy. In fact, nearly all official governing bodies, including the American College of Obstetricians and Gynecologists (ACOG) and the World Health Organization (WHO) suggest that caffeine up to 200mg per day is safe (10). That’s the equivalent of about two 8-oz cups of coffee, depending on brewing methods.
It is worth mentioning that this is a very conservative estimate. Again, there are almost no high-quality studies suggesting that caffeine intakes above this are harmful or cause preterm births or increased miscarriage. Even ACOG, states that they are unable to find a correlation between high caffeine intake and miscarriage. But for now, until the evidence is stronger, this is the most reliable recommendation that we have.
When I was pregnant, I switched from coffee to Americanos, so that I could better assess the amount of caffeine I was taking in each day. Each shot of espresso is equivalent to about 75mg of caffeine, so I had one Americano in the morning and one in the afternoon and never gave it a second thought.