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

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:

• Avoid drugs and alcohol.
• Eat well, making sure to get plenty of folic acid and calcium.
• Exercise once you get your doctor's OK.
• Skip deli meats, soft cheeses (like feta), and hot dogs that could carry listeriosis.
• Don't change the litter box. Cats can carry a harmful parasitic infection called toxoplasmosis.
• Stop smoking — or don't start.
• Tell your doctor about all medications you're taking. Unless your doctor says otherwise, many medicines — both prescription and over-the-counter — should be avoided during pregnancy.
• Avoid abdominal trauma.
• Know your family's medical and genetic history.
• Talk to your doctor about which immunizations you should and shouldn't get during pregnancy.

If you're pregnant and worried about your caffeine consumption, talk to your doctor or midwife. But until the experts can all agree on exactly how much caffeine is OK and how much isn't, it's probably a good idea to limit or skip caffeine for the remainder of your pregnancy.

Source: American Journal of Obstetrics and Gynecology, January 2008.