Avoiding caffeine as much as possible is the safest bet if you're pregnant, says the American Pregnancy Association. Caffeine can raise your heart rate and blood pressure. It can boost urination, which can dehydrate you. And it can cross the placenta, affecting your baby's movement and sleep patterns.Some studies link caffeine to miscarriage, while others do not, according to the March of Dimes.However, moderate caffeine consumption–less than 200 milligrams a day–"does not appear to be a major contributing factor in miscarriage or preterm birth," adds the American College of Obstetricians and Gynecologists.
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Pregnant women are among the most common sufferers of chronic heartburn, a condition also known as gastroesophageal reflux disease (GERD). Heartburn is the result of acid reflux, the term used to describe stomach acid that backs up into the esophagus (the narrow tube that connects the mouth and the stomach). Hormonal changes during pregnancy and the pressure exerted on the stomach by the growing fetus can cause acid reflux to happen more frequently.

The good news is that heartburn usually goes away once the baby is born. In the meantime, there are several diet and lifestyle changes—as well as certain medications—that can make expecting moms feel better.