Gestational diabetes mellitus (GDM) is a form of diabetes that develops during pregnancy in women who have not previously been diagnosed with diabetes. This condition arises when the body cannot produce enough insulin, or effectively use the insulin it produces, to meet the increased demands of pregnancy. The result is elevated blood sugar levels, which can affect both the mother and the developing baby.
During pregnancy, hormones produced by the placenta can increase a woman’s resistance to insulin, known as insulin resistance. Insulin is a hormone that helps glucose enter cells for energy. When the pancreas cannot produce enough additional insulin to overcome this resistance, blood sugar levels rise, leading to a diagnosis of GDM.
Unlike Type 1 or Type 2 diabetes, GDM specifically begins during gestation and typically resolves after childbirth. However, experiencing gestational diabetes can indicate a higher risk for developing Type 2 diabetes later in life. Understanding this unique characteristic is important for both immediate management and long-term health considerations.
Factors That Increase Risk
Several factors can increase a woman’s likelihood of developing gestational diabetes mellitus. One significant factor is pre-pregnancy weight, as being overweight or obese contributes to increased insulin resistance.
A family history of diabetes, particularly in a parent or sibling, also raises the risk, suggesting a genetic predisposition. Women who have had GDM in a previous pregnancy are at a higher risk of developing it again in subsequent pregnancies. Advancing maternal age, specifically being over 25 years old, is another contributing factor.
Certain ethnic backgrounds, including Hispanic, African American, Native American, and Asian women, have a higher prevalence of GDM, indicating potential genetic or lifestyle influences. Additionally, a history of polycystic ovary syndrome (PCOS) can increase the risk due to the underlying insulin resistance often associated with the condition. These factors collectively highlight the varied influences on GDM development.
How It Is Diagnosed
Gestational diabetes mellitus is screened for between the 24th and 28th weeks of pregnancy, though earlier testing may occur if a woman has significant risk factors. The initial screening involves a glucose challenge test (GCT). During this test, a woman drinks a solution containing 50 grams of glucose, and her blood sugar level is measured one hour later.
If the results of the GCT are elevated, a more definitive diagnostic test, the oral glucose tolerance test (OGTT), is performed. For the OGTT, the woman fasts overnight before the test. Her blood is drawn to measure fasting glucose, and then she consumes a more concentrated glucose solution, typically containing 75 or 100 grams of glucose.
Subsequent blood draws are taken at one, two, and sometimes three hours after drinking the solution. A diagnosis of GDM is confirmed if two or more of the blood sugar readings meet or exceed specific threshold levels. This multi-step process helps accurately identify women who require further management to maintain healthy blood sugar levels during pregnancy.
Managing Your Condition
Managing gestational diabetes mellitus involves lifestyle modifications. Dietary changes are a fundamental component, focusing on balanced meals with controlled carbohydrate intake. Opting for complex carbohydrates, such as whole grains, fruits, and vegetables, helps to release glucose more slowly into the bloodstream, preventing sharp spikes.
Regular physical activity is also recommended, as it helps the body use insulin more efficiently and lowers blood sugar. Moderate exercise, like brisk walking or swimming, for at least 30 minutes most days of the week, can improve glucose control. Consulting with a healthcare provider can help tailor a safe and effective exercise plan.
Consistent blood sugar monitoring is important to track glucose levels throughout the day and assess the effectiveness of management strategies. If lifestyle changes alone are not sufficient to maintain target blood sugar levels, medication may be prescribed, such as oral medications or insulin injections. Close collaboration with a healthcare team ensures appropriate adjustments to the management plan as pregnancy progresses.
Effects on Mother and Baby
For the mother, there is an increased risk of developing preeclampsia (high blood pressure). Additionally, poorly managed GDM can increase the likelihood of needing a Cesarean section.
Babies born to mothers with uncontrolled GDM may experience increased birth weight, a condition known as macrosomia, which can complicate vaginal delivery. These infants are also at a higher risk for preterm birth, respiratory distress syndrome, and low blood sugar (hypoglycemia) after birth.
In the long term, mothers who have had GDM have a higher risk of developing Type 2 diabetes later in life. For the baby, being exposed to high glucose levels in utero can increase their risk of obesity and developing Type 2 diabetes later in childhood or adulthood. Effective management during pregnancy substantially reduces these potential adverse outcomes.