Pregnancy can cause a woman's body to change shape and size several times before the baby arrives. It isn't uncommon for a woman to wake up and be unable to button the pants she wore the night before. Sometimes clothes are uncomfortably tight or they place pressure on certain parts of the body. Marjorie Greenfield, M.D., of DrSpock.com points out that evidence doesn't reveal medical consequences of wearing tight clothes during pregnancy but various discomforts can develop.
The California Pacific Medical Center's Women & Infants Center points out that wearing tight-fitting clothes, especially at the waist, can lead to heartburn. Heartburn or acid reflux are common discomforts during pregnancy. These occur due to digestive slowness from an increase in progesterone in the body during pregnancy. When the stomach contents sit longer in the stomach due to this slowness, the risk of the contents flowing upwards increases. The fullness in the abdomen from the growing uterus, amniotic sac and baby can put pressure on the stomach and force the contents back up the chest too. The pressure from tight clothing can push on the stomach and force the contents upwards, creating heartburn.
The American Pregnancy Association suggests another effect of wearing tight, unbreathable clothing is increased vaginal yeast infections. Pregnant women experience an increase in vaginal secretions during pregnancy. This, combined with tight underwear, can create the perfect environment to allow yeast that naturally occurs in the vagina to overproduce and cause an infection.
Wearing tight-fitting clothes can cause pain in a number of areas of the body during pregnancy. This includes the abdomen, chest and arms. A woman's bra size can increase both in the elastic around the middle and the cup itself. Tight-fitting bras can cause pain in the breasts, under the arms and the back. As the woman nears labor, the breasts may be even more susceptible to pain or complications from tight-fitting bras. This is due to the breasts preparing to lactate when the baby is born. Putting pressure in one area of the breast too long can cause the milk ducts to become clogged even before a woman is breastfeeding. The result can be pain, redness and a knot.
Wearing tight-fitting clothes, whether pregnant or not, can slow circulation in the body. In early pregnancy the woman's blood vessels expand in preparation for the increased blood volume that develops to provide for the placenta and baby. Before the blood volume increases to fill the vessels, a woman can experience hypotension, or low blood pressure, easily. Examples of this include standing up quickly from a kneeling, sitting or lying position. Tight clothes in the limbs, such as the arms and thighs, can cut off blood circulation and create a numbness or tingling sensation.