An upset stomach includes feelings of general discomfort, indigestion, flatulence, and heartburn. There are no statistics exactly the number or percentage of women who regularly an upset stomach in the two weeks or so before their periods, upset stomach is common enough to be grouped among the so typical PMS symptoms by medical experts.

Diet, Stress, and Other Causes

An upset stomach can occur for many reasons; PMS is among them. Diet, stress, and side effects from medications are of the most common causes, and each plays a role in PMS.

A 2006 survey showed that nearly one in three people stressed also had an upset stomach. The survey found that of men and women who experienced stress also experienced frequent upset stomach or indigestion. Research has also shown women prone to stress are also more likely to feel PMS symptoms.

Some medications used to treat PMS pain or insomnia list an upset stomach as one of their main side effects. Diets rich in gasproducing foods, poor in nutrients, high in fat, and low in fiber— typical for many women with PMS— often lead to an upset stomach.

Nonsteroidal Anti-inflammatory Drugs: The Chicken or the Egg?

Many women don't blink an eye when they pop a couple of Motrin or ibuprofen tablets to reduce PMS-associated pain. But one of the side effects of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin IB) and naproxen sodium (Aleve), is upset stomach. If you're in the habit of taking NSAIDs to relieve premenstrual pain, you may actually be making some of your symptoms worse. Consider whether taking NSAIDs is causing or contributing to your upset stomach, or consider taking these drugs with an antacid.