Gestational diabetes mellitus (GDM) is marked by high blood sugar levels that first appear during pregnancy. This occurs because pregnancy hormones create resistance to the body’s own insulin, the hormone responsible for regulating blood glucose. When the pancreas cannot produce enough extra insulin to overcome this resistance, glucose builds up in the bloodstream instead of being absorbed for energy. GDM requires active management to protect the health of both the pregnant person and the developing fetus, often involving the discussion of insulin therapy.
Understanding Patient Autonomy in Pregnancy
A pregnant person retains the legal and ethical right to accept or refuse any medical treatment, including insulin for gestational diabetes, as they are considered a decisionally capable adult. This principle, known as patient autonomy, is a fundamental tenet of medical care and is not diminished by pregnancy. Informed consent requires a healthcare provider to fully explain the risks and benefits of a proposed treatment, as well as the risks associated with refusing it.
The right to refuse treatment is nearly absolute, even if the refusal is against medical advice or could potentially affect the fetus. Healthcare organizations discourage the use of coercion, threats, or judicial intervention to compel a patient toward a specific clinical decision. The professional relationship is with the pregnant person, who makes decisions based on their goals, values, and priorities.
Open and honest communication is crucial when a patient expresses concerns about starting insulin. This dialogue ensures the patient’s concerns are taken seriously and allows the healthcare team to explore alternatives. While a patient has the right to refuse insulin, the care team will clearly outline the potential outcomes of uncontrolled blood sugar and the need for increased surveillance following that refusal.
Health Risks of Untreated Gestational Diabetes
The recommendation for treatment, including insulin, stems from the risks associated with uncontrolled high blood sugar levels. When maternal glucose levels are elevated, excess glucose crosses the placenta, causing the fetal pancreas to produce high levels of insulin. The fetus converts this extra glucose into fat, which leads to excessive growth.
A common result is fetal macrosomia, meaning the baby is significantly larger than average, often defined as weighing over 8 pounds, 13 ounces (4,000 grams). A large baby increases the likelihood of birth injuries, such as shoulder dystocia, where the baby’s shoulder becomes lodged behind the mother’s pubic bone during delivery. This can cause nerve damage to the baby or require an emergency Cesarean section.
After birth, the newborn is at risk for neonatal hypoglycemia, or dangerously low blood sugar, because their body is accustomed to producing high levels of insulin to manage the mother’s high glucose. This low blood sugar requires immediate monitoring and treatment in the neonatal intensive care unit (NICU). Uncontrolled GDM also increases the mother’s risk of developing preeclampsia, characterized by high blood pressure and potential organ damage.
Long-term risks are a concern for both mother and child. Approximately 50% of people who have GDM will develop Type 2 diabetes later in life. The child is also at an increased risk for developing obesity and Type 2 diabetes as they grow older.
Non-Insulin Management Approaches
If blood sugar levels are only mildly elevated, or if a patient refuses insulin, the first line of treatment involves lifestyle modifications. The primary alternative is Medical Nutrition Therapy (MNT), which focuses on careful dietary modification and carbohydrate management. This involves working closely with a dietitian to create a balanced meal plan that distributes carbohydrate intake evenly throughout the day to prevent blood sugar spikes.
MNT focuses on selecting complex carbohydrates with a low glycemic index, such as whole grains, brown rice, and certain vegetables, which release sugar into the bloodstream more slowly. Regular physical activity also increases insulin sensitivity, helping to lower blood glucose levels. Healthcare providers recommend aiming for at least 150 minutes of moderate-intensity activity per week.
If MNT and exercise alone are insufficient, oral medications may be used as a second-line treatment before initiating insulin. The two most common oral agents are Metformin and Glyburide (also known as Glibenclamide). Both can be effective, but some patients may still require insulin later in the pregnancy if glucose control remains inadequate.
Metformin and Glyburide
Metformin works primarily by improving insulin sensitivity and reducing glucose production by the liver. It is sometimes favored because it is associated with less maternal weight gain and a decreased risk of pregnancy-induced hypertension compared to insulin. Glyburide stimulates the pancreas to release more insulin.
Medical Monitoring and Follow-Up After Declining Insulin
When a patient declines the recommended insulin therapy, the medical team must increase surveillance to protect against the risks of uncontrolled high blood sugar. Daily self-monitoring of blood glucose (SMBG) becomes a strict requirement, often involving checks four times a day: fasting, and one hour after each major meal.
The patient is expected to maintain meticulous logs of these glucose readings, as well as detailed records of their diet and physical activity. These records are reviewed frequently, sometimes weekly or bi-weekly. If the blood sugar targets are not consistently met—for example, if fasting glucose remains above 95 mg/dL or post-meal glucose exceeds 140 mg/dL—the care team will urge a change in the treatment plan.
Beyond glucose monitoring, enhanced fetal surveillance is typically initiated in the third trimester. This involves regular testing performed more frequently to detect any signs of fetal distress, which could necessitate immediate reconsideration of insulin therapy or, in severe cases, an early delivery to prevent stillbirth. Enhanced fetal surveillance includes:
- Regular Non-Stress Tests (NSTs), which monitor the baby’s heart rate in response to movement.
- Biophysical Profiles (BPPs), which use ultrasound to assess fetal well-being.
- Assessment of fetal breathing and movement.
- Assessment of amniotic fluid levels.