Cut down on coffee and caffeinated soda if you are trying to conceive. That is the message of a new study from the National Institutes of Health that finds a woman is more likely to miscarry if she – or her partner – drank two or more caffeinated beverages prior to conception. And the study found women who drank more than two caffeinated drinks a day during the first seven weeks of pregnancy also were at a high risk of miscarriage.
“The impacts of caffeine on pregnancy have been suspected for some time,” says Joseph Stanford, M.D., an OB/GYN with University of Utah Health Care. “This study was a better look at the question, because it had both women and men assess caffeine intake, vitamin intake, and other factors every day while they were trying to conceive. Most prior studies have asked just women about these factors after the fact.”
While the study shows a strong link between caffeine and miscarriage, it does not explain why. There are several possible explanations. “Caffeine might affect blood flow to the developing embryo in the uterus, or have a direct effect on the embryo,” says Stanford. “Prior to conception, it could impact the final maturation stages of egg or sperm development.”
The study also doesn’t examine if the caffeine is impacting the woman more prior to conception or right after conception. “It may not be completely possible to separate the impact of caffeine intake in women before conception versus very early pregnancy, since these are closely correlated,” says Stanford. “So we don’t know which time window in women has the highest impact. However, one of the most interesting things about this study is good evidence that there is impact of high caffeine intake for miscarriage in both women and men.”
The study is not all bad news, though. While the researchers found caffeine consumption increased miscarriage risk, they also found a decrease in risk among women who took multivitamins, which has been previously documented. “This is probably due to the folic acid in the vitamins,” says Stanford. “Folic acid is known as a key nutrient for rapidly dividing cells. Cells are multiplying rapidly in the early embryo.”
Much more needs to be studied when it comes to understanding pregnancy and miscarriage – especially as couples are conceiving later in life. This study points out that at any age it is important to consider lifestyle choices when it comes to trying to conceive. “When you are planning a pregnancy, it is important to be the healthiest you can be,” says Stanford.