A new study conducted by Kaiser Permanente in California, and published in the American Journal of Obstetrics and Gynecology, shows a link between caffeine consumption and miscarriage risk. The study looked at over 1000 women, they were interviewed at an average of 10 weeks into their pregnancy. 16% of the women were found to have miscarried. Of those who miscarried, 60% of them had consumed up to 200mg of caffeine everyday, with another 15% saying they consumed more than 200mg of caffeine daily. By contrast only 25% of the women who miscarried had reported not consuming any caffeine.
Several studies have been conducted to determine the effect of caffeine on early pregnancy, however, previous research studies did not control for morning sickness (which often results in a reduced risk of miscarriage). In this particular study they did control for morning sickness and found an increased risk of miscarriage based on caffeine consumption even among those women who reported having morning sickness in early pregnancy.
Not a lot is known about why caffeine causes an increased risk of miscarriage, however, it is thought that since caffeine crosses the placenta is affects cell development and may even impact the blood flow from mom to baby.
Doctors have long cautioned women against consuming too much caffeine during pregnancy, but didn’t really know how much was too much. The results of the study seem to indicate that any amount of caffeine increases the risk of miscarriage, but that 200mg or more causes the greatest increased risk. 200mg of caffeine is equivalent to 2 cups of coffee, 4 caffeinated sodas, or 4 cups of tea.
I wasn’t a caffeine drinker before my pregnancy so it was easy for me not to consume any caffeine during my pregnancy. Women who rely on caffeine to get them going in the morning are likely to have a harder time staying away from or reducing the amount of caffeine they consume during pregnancy. A few things you can do to combat the exhaustion of the first trimester without turning to coffee are: get enough sleep (nap more, adjust your schedule so you can sleep more, etc), eat a healthy, balanced diet, and exercise.
Talk to your doctor about the results of this study and determine what you can do to reduce your own risk for miscarriage.