Just Two Cups of Coffee a Day Can Double Miscarriage Risk, Says Study

It's not news that downing a ton of caffeine-filled beverages while you're expecting isn't a good idea. But doctors have long been divided about what's safe and what's not when it comes to caffeinated pick-me-ups during pregnancy, a time when many women also happen to be at their sleepiest. Now, though, one new study suggests that limiting or nixing caffeine for expectant moms is a must — that as few as two cups of coffee a day can actually double a woman's risk of miscarriage.

Many doctors tell their pregnant patients that one or two 6- to 8-ounce (oz.) cups of coffee, tea, or soda with caffeine a day won't harm the baby. But some previous studies have shown that caffeine consumption of anywhere from 150 to 300 milligrams (mg) a day (about 1½–3 cups of coffee) can put a pregnancy at higher risk of miscarriage or a low birth-weight baby.

This latest study, involving interviews with more than 1,000 pregnant women, goes even farther to say that 200 mg or more of caffeine (that's about 2 cups of regular coffee or five 12-ounce cans of caffeinated soda) per day makes it twice as likely that a pregnant woman will miscarry. A quarter of the women who had 200 mg or more each day had a miscarriage, versus the 12.5% of women who miscarried and said they hadn't had any caffeine during pregnancy at all.

That's why this group of researchers says women should cut out caffeine or have no more than one cup of java, especially during the first few months of pregnancy, when most miscarriages happen.

More on Miscarriages

Sadly, 1 in 5 pregnancies, on average, will end in a miscarriage (when a pregnancy spontaneously ends before an embryo or fetus has developed enough to survive outside of the womb).

Miscarriages often happen even before a woman knows she's pregnant — usually in early pregnancy, before 20 weeks' gestation. In most cases, a miscarriage simply can't be prevented because it's the result of:

• a genetic or chromosomal change that occurs during conception or early fetal development
• imbalances of hormones
• abnormalities of — or problems with — the uterus, cervix, or placenta

However, certain factors (like excessive caffeine consumption) can put a woman at a higher risk for losing a pregnancy, including:

• a woman's age (the odds go up as women approach 40)
• infections (like syphilis, toxoplasmosis, German measles, rubella, influenza, and listeriosis)
• chronic and/or untreated illnesses (like diabetes; lupus; high blood pressure; or kidney, heart, or thyroid disease)
• exposure to environmental and workplace hazards (like radiation or toxic agents)
• certain medications (mostly prescription, such as the acne drug Accutane)
• use of alcohol or illegal drugs
• smoking, which sends nicotine and other chemicals into the bloodstream, causing the blood vessels in the placenta to spasm, which decreases the blood flow to the uterus. Smokers also have a lower level of oxygen in their blood, which means the fetus gets less oxygen.

What This Means to You

Miscarriages often can't be prevented. But you can take a few practical precautions to up your chances of having a healthy pregnancy: