Some women develop diabetes during pregnancy, and since it only lasts until delivery, it is referred to as gestational diabetes. Like the typical form of diabetes, the problem occurs when the pancreas does not make the amount of insulin that the body needs. During pregnancy, hormones interfere with the way the woman's pancreas works, which is why hormone interference is considered one of the main causes of gestational diabetes. Being overweight, as well as having delivered big babies in the past, can also be causes of gestational diabetes. Family history of diabetes, birth defects in other children, and high maternal age can all add to the chances of having diabetes when pregnant.
Those with diabetes have high blood sugar, as their body does not break down glucose properly. This is usually a result of a lack of the proper amount of insulin. In most pregnant women, the pancreas responds to the need for more insulin by simply making more, but for some women, the placenta interferes with the ability to do so. This is due to the mass amount of hormones that the placenta secretes during pregnancy, eventually resulting in insulin resistance. Thus, the presence of hormones that do not allow the pancreas to do its job is one of the main causes of gestational diabetes.
Weight also often plays into this issue, as overweight women are particularly at risk for pregnancy-induced diabetes. A body mass index, or BMI, of over 30 is usually a sign that a woman should be tested for diabetes in pregnancy. Another way that weight is considered one of the main causes of gestational diabetes is the fact that having delivered a large baby in the past is also a risk factor. Most doctors' opinions vary on whether the minimum weight for a large baby is considered 8 pounds, 13 ounces (4 kg), or 9 pounds, 14 ounces (4.5 kg), but either way, the birth of a large baby in the past is a risk factor.
There are a few other details that can be considered causes of gestational diabetes. Women over age 35 are often automatically tested for this medical issue since it tends to occur most in those of advanced maternal age. In fact, many doctors even test any woman over age 25 just to be sure. A history of either gestational diabetes in female relatives, or the typical form of diabetes in any family member, can also put a woman at risk for pregnancy-induced diabetes. Finally, having had children with birth defects or who were stillborn can also be an indicator of this medical issue. Patients who are concerned about these risks should discus them with their obstetricians, and ask what their testing policy is.