Gestational diabetes is thought to occur due to hormonal and other changes that take place in the woman’s body during pregnancy. These changes predispose some women to become resistant to insulin.
Insulin resistance develops mainly due to hormonal changes. More specifically, there occurs an imbalance between the levels of certain hormones that affect insulin in the body of a pregnant woman. The hormones that elevate blood sugar override the hormones that lower it.
Among these hormones are:
- Estrogen and progesterone
- Human placental lactogen
- Placental insulinase
- Growth hormones.
Other changes that occur in the body of a pregnant woman and contribute to the disease include: eating more, moving less and having large fat deposits.
All these changes allow the fetus access to more nutrients needed for its growth and development, and the woman’s body compensates by producing more insulin. But some women are less able to produce enough insulin to overcome resistance and in some women even this extra insulin is not enough to keep sugar levels normal, resulting in gestational diabetes.
There are also numerous factors that raise a woman’s risk of developing diabetes. They include:
- Obesity or being overweight. Obese women may already have insulin resistance before they become pregnant. Putting on too much weight during pregnancy can also be a risk factor.
- Family history. If a first degree relative (parent, sister or brother) has diabetes.
- Personal history. If a woman had prediabetes (elevated blood sugar, but not high enough to be diagnosed with diabetes) that could be a precursor to diabetes.
- A history of gestational diabetes. If a woman had gestational diabetes during a previous pregnancy.
- Poor obstetric history. If a woman had previously had a miscarried fetus, a stillborn child or a baby with a birth defect.
- History of macrosomic delivery. If a woman had previously given birth to a large baby weighing over 9 pounds.
- Ethnicity. If a woman is from South Asian, African Caribbean or Middle Eastern background, including Native Americans, African-Americans, Hispanics and Chinese.
- Maternal age. The risk factor increases as the woman gets older, especially over 35.
- Hormonal disorders, especially polycystic ovary syndrome.
- Hypertension and other health complications.
- Medications. Taking certain medications like beta-blockers for high blood pressure, glucocorticoids for asthma or an autoimmune disease, or antipsychotic drugs for mental health disorders.
Unfortunately, there is no way to predict the development of gestational diabetes, but there are factors that can be avoided and ways to lower the risk.