Pregnancy has many different physical effects on women; in addition to adjusting to the increased weight of a growing baby, their bodies also change in other significant ways. Blood volume increases, and the heart works harder to distribute blood. Hormone levels change. The digestive tract, too, is affected by pregnancy, with the result that sour stomach is a common physical complaint.
There are many reasons for sour stomach during pregnancy, most of which are hormone-driven. Explains Dr. Miriam Stoppard in her book, "Conception, Pregnancy and Birth," a pregnant woman's digestive tract slows significantly, so as to extract every bit of nutrition from the food she eats. This means food sits in her stomach for a longer period, which can result in an uncomfortable sensation of fullness, a stomachache, or simply the sensation of sour stomach.
Sour stomach and stomach discomfort aren't necessarily limited to sensations coming from the stomach itself. Pregnant women can actually feel discomfort all along the digestive tract. Particularly late in pregnancy, it can be quite difficult to determine whether an unpleasant sensation is coming from the stomach or from the intestines or esophagus. In their book, "You: Having A Baby," Drs. Michael Roizen and Mehmet Oz explain that late in pregnancy, babies push their mothers' digestive organs far away from their normal locations, somewhat confounding abdominal sensation.
Sour stomach can even be the way in which certain women experience morning sickness. Heidi Murkoff and Sharon Mazel, in their book, "What To Expect When You're Expecting," point out that not all women experience morning sickness in the same way. Some vomit, while others feel faintly seasick. Still others might have the sensation that something just "isn't right" in their stomachs. Most women, Murkoff and Mazel point out, get some relief from morning sickness by the end of the first trimester.
Tthere are several potential remedies to sour stomach, depending on the likely cause. Most physicians consider herbal teas sold in the grocery store to be safe during pregnancy, note Roizen and Oz. As such, some women find chamomile tea to help in alleviating symptoms. Sour stomach due to intestinal gas or esophageal reflux is more difficult to treat, but eating small, frequent meals might help. Staying in a seated or standing position for some time after eating also might reduce unpleasant sensations.
Dr. Stoppard recommends that pregnant women always consult their obstetrician before taking any over-the-counter medication; many are safe during pregnancy, but some are not. Most physicians allow women to use certain gas relieving medications like Gas-X and antacids like Tums to treat symptoms of sour stomach, but it's always best to have a physician's blessing before resorting to pharmaceutical treatment of a physical complaint during pregnancy.