Everybody (pregnant or not) has some gas. You may have even more gas than usual during pregnancy. Don't be surprised if you find yourself belching like a beer drinker or having to unbutton your pants to relieve bloating many weeks before you're actually showing. That's primarily because the major doses of progesterone your body produces early in pregnancy relax smooth muscle tissue throughout your body, and that includes your gastrointestinal tract. This relaxation slows your digestive processes, which can cause more gas, bloating, burping, flatulence, and generally miserable sensations in your gut, especially after a big meal. In later pregnancy, your growing uterus crowds your abdominal cavity, which can further slow digestion, and pushes on your stomach, making you feel even more bloated after eating. You may also start to experience heartburn or constipation during pregnancy even if you've never had it before.

There are two ways that gas gets caught in the digestive tract. It happens when you swallow air, and it's also a normal by product when undigested foods get broken down by bacteria in your colon. Most gas in the stomach is the result of swallowing air and is generally released by burping, though a small amount can continue down to the colon to be released at the other end.
Normally gas that causes flatulence is produced when food that was incompletely digested in the stomach and small intestine is broken down in the large intestine by the bacteria that reside there. Certain carbohydrates are the main culprits. Protein and fat are not major gas producers, though fats can contribute to a sense of bloating because they slow stomach-emptying time.
How does pregnancy cause an increase in gas? Pregnancy slows digestion, giving the bacteria more time to work on the undigested material before it's excreted, so you have increased fermentation and hence more gas. Actually, anything that slows down bowel function can increase gas, so constipation can also cause you to feel more gassy and bloated as well.

Some people get a lot of gas from certain foods that don't bother others at all. A prime example is lactose intolerance: Some people don't make enough lactase — the enzyme that breaks down lactose (the sugar in dairy products) — so they get bloated and gassy if they have too much milk or ice cream. There's also individual variation in the balance of bacteria in the colon, and some think that, too, may affect how much gas is made.

Diet Helps To Relief Gas Problem

The most effective way to reduce gas may be to cut back on the foods that seem to be primarily causing it. You may want to start by cutting out the most common culprits and if that gives you relief, start adding these foods back into your diet one by one to see if you can pinpoint what's causing the problem for you. Keeping a food diary can help you see associations between eating certain foods and having more gas.

The foods most likely to cause gas are beans, cabbage, cauliflower, Brussels sprouts, broccoli, and asparagus. These foods all contain a sugar called raffinose that causes gas for a lot of people. Other people have trouble with onions, pears, and sodas and fruit drinks sweetened with the sugar fructose. (Soda and fruit drinks are just empty calories anyway, and the carbonation in sodas can exacerbate bloating.)
Some starches (such as pasta and potatoes but not rice) can cause gas for some people, and some fibre-rich foods (such as oat bran, beans, and many fruits) cause gas because they're normally broken down in the large intestine. One exception is wheat bran, which passes through your system without getting broken down. (This makes wheat bran a winner if you have constipation and need more fibre but also suffer from flatulence.)

Those who are lactose intolerant will find that dairy products give them gas. If you're highly intolerant you'll likely already be aware of this before pregnancy, since dairy may even cause diarrhoea and abdominal pain for you. But if you're only somewhat intolerant, you may start to feel some distress during pregnancy if you dramatically increase your intake of dairy products. If you think this is a problem for you, you can find lactose-free or soy milk in many supermarkets. (If you aren't drinking any kind of milk, you'll probably need to take a calcium supplement.)

Finally, you may want to avoid very fatty or fried foods. They don't cause gas, but they can make you feel more bloated because they slow down digestion.

These suggestions may also lessen the frequency and severity of your symptoms:

                                                                                                                                                                     Don't eat big meals. Instead, eat several small meals throughout the day.

  • Don't talk while you're eating. Take your time eating, and chew thoroughly.

  • Limit your fluid intake during meals (take it between meals).

  • Drink from a glass, not a bottle or a straw, and don't gulp your beverages.

  • Avoid carbonated drinks.

  • Sit up while you're eating or drinking, even if it's just a small snack.

  • Wear loose, comfortable clothing; avoid any tightness around your waist and tummy.
  
  • Don't chew gum or suck on hard candies.

  • Avoid products sweetened with Sorbitol (certain gums and candies).

  • Exercise — even a brisk walk can help your sluggish digestive tract.

  • Avoid constipation (can make flatulence worse and no doubt a sense of abdominal bloating).

  • Don't smoke (this is a habit you should break before getting pregnant).

  • Consider practicing yoga (or a similar discipline) for relaxation and good breathing techniques.     (Some people tend to swallow more air when they're excited or anxious if they're prone to       hyperventilating.)

  • If the above relief measures don't help, ask your practitioner if you can take an over-the-counter     anti-gas remedy that contains simethicone. (Activated charcoal tablets, another anti-gas remedy,     aren't safe during pregnancy.)

Can gas pain ever be a sign that something is wrong?

Call your practitioner if your gas discomfort ever feels more like abdominal pain or cramping or is accompanied by blood in your stool, severe diarrhea, or constipation, or an increase in or new bout of nausea and vomiting.