What Happens to Blood Sugar During Pregnancy?

A woman's blood sugar is often higher than normal during pregnancy, especially during the first and third trimesters. Nearly 5% of pregnant women do not make the requisite amount of insulin needed to process the excess glucose their bodies create, leading to pregnancy-induced or gestational diabetes. This can result in health issues for both mother and baby; as a result, it's very common to test a woman's blood sugar during pregnancy. In some cases, a woman's blood sugar can become too low, especially if she is experiencing severe morning sickness.

The placenta creates hormones that can limit the amount of insulin a woman's body can use and causing a rise in blood sugar. This typically occurs during the first trimester, when hormone changes happen suddenly, and may continue to get worse as the fetus grows. Gestational diabetes is often diagnosed between the 24th and 28th weeks of pregnancy. The pancreas, the organ responsible for insulin production, needs to make as much as three times more insulin during pregnancy than it does when a woman is not pregnant. If insulin production fails to keep up, a woman's blood sugar levels can become dangerously high.

While most pregnant women have a slight uptick in blood sugar, it is typically within an acceptable range. A small percentage of women become intolerant to glucose, the sugar found in blood, and experience gestational diabetes. These women typically have to eat a specific diet, exercise regularly, undergo routine blood sugar testing, and they may require insulin during their pregnancy. In most cases, the problem stops shortly after giving birth, although in very rare cases, gestational diabetes can develop into regular diabetes.

This rise in blood sugar during pregnancy can cause some health issues for the woman, but is typically not life threatening. Blurred vision, excessive thirst or urination, and weight loss are the most common. The main concern is the health of the fetus, since high blood sugar can cause birth defects, miscarriages early in pregnancy, issues with delivery, and increases the risks of stillbirth. When left untreated, the baby may have low blood sugar once born, which can put his or her life at risk if untreated.

A woman's blood sugar is often tested with urine samples and a glucose tolerance test during the second trimester. If results from these tests come back abnormal, a woman will likely have to take a three hour glucose test to determine if gestational diabetes is a risk. Eating well during pregnancy and exercising regularly can greatly reduce the chances of developing this problem.

In rare cases, a woman's blood sugar can become too low. This typically occurs when a woman is not eating enough or is having difficulty keeping food down, which is common during the first trimester. Eating small, light meals several times a day can often resolve the problem. In rare cases, a woman with low blood sugar during pregnancy may require hospitalization.