GESTATIONAL DIABETES MELLITUS (GDM)

Gestational diabetes mellitus occurs when a patient’s pancreatic function is not sufficient to overcome the insulin resistance associated with pregnancy. In pregnancy, glucose demands increase as the fetus grows. The “insulin-antagonistic” properties of placental hormones affect the patient by causing normal insulin resistance of pregnancy. This allows a proper supply of glucose for the growing fetus. In gestational diabetes mellitus, the pregnant patient is unable to process glucose sufficiently in the body and hyperglycemia occurs (Durnwald, 2022a).

Individuals who have had GDM are also more than nine times as likely to develop type 2 diabetes (Durnwald, 2022b).

Maternal and Fetal Complications

A variety of maternal and fetal complications are associated with GDM.

Infants born to patients with gestational diabetes mellitus are significantly more likely to be macrosomic (birthweight >4.5 kg). This occurs due to fetal hyperinsulinemia as a result of maternal hyperglycemia, which stimulates excessive growth. These large infants may have difficulty maneuvering the birth canal, and a cesarean section may be required. If vaginal delivery is attempted, the infant is at risk for shoulder dystocia and related birth injuries. Patients also have an increased frequency of gestational hypertension, preeclampsia, polyhydramnios, and stillbirth.

After delivery, the newborn infant’s blood glucose must be monitored regularly for hypoglycemia due to the sharp decrease in available glucose after the umbilical cord is cut. The newborn’s pancreas continues to produce insulin after delivery despite the decrease in serum glucose. This adds to the potential instability of the infant’s blood glucose. Infants are also at risk for hypocalcemia, hyperbilirubinemia, hypomagnesemia, polycythemia, cardiomyopathy, and respiratory distress syndrome as a result of gestational diabetes (Durnwald, 2022a).

Medical Treatment

Pregnant patients are routinely screened for GDM at 24–28 weeks’ gestation. In order to diagnose gestational diabetes, patients drink 50 grams of oral glucose solution. After one hour, a blood sample is obtained and tested for glucose tolerance. A glucose level of ≥130–140 mg/dL is considered a positive screen, and further investigation is warranted. A three-hour glucose tolerance test (with a 100 gram oral glucose solution) is then typically performed.

Most patients with GDM are treated through diet and exercise. Patients are advised to eat a diet favoring fruit, vegetables, whole grains, and fish and low in red and processed meat, refined grains, and high-fat dairy. Some patients may require insulin or oral hypoglycemia agents to manage gestational diabetes mellitus.

Nursing Care

It is important for the nurse to monitor serum glucose levels throughout the pregnancy of patients with GDM. A referral to a dietitian may also be necessary. The nurse may also conduct regular fetal surveillance, including nonstress tests or biophysical profiles starting at 32–36 weeks’ gestation and until delivery.

Patient Teaching

The nurse working with patients diagnosed with GDM is often responsible for teaching the patient to self-monitor and record glucose at home. In addition, the nurse may teach patients about proper diet and safe exercise during pregnancy.

During prenatal visits, the nurse reviews the blood glucose and diet logs to make recommendations about monitoring, medication administration, and diet. Patients may also need to learn how to self-administer insulin. The nurse ensures that the patient can comfortably and appropriately check blood glucose levels and administer insulin by requesting a return demonstration.

It is imperative that the nurse teach patients with gestational diabetes the signs and symptoms of hypoglycemia, which include shakiness, anxiety, headache, hunger, cold, clammy skin, and tingling around the mouth. The patient is taught to closely monitor for hypoglycemia and to notify the healthcare practitioner immediately if signs and symptoms are noted.

Hypoglycemia in those with GDM is treated by immediately eating 10–20 g of a fast-acting carbohydrate snack. Eight ounces of skim milk may be used, as it tends to dampen the rapid elevation of glucose followed by rapid decline that can result in pregnant women with diabetes from consuming a pure simple sugar (Durnwald, 2022b).

Since the potential for developing diabetes is significant in patients with gestational diabetes, it is important that patients understand the need for follow-up evaluation after delivery. Patients should continue to watch for signs and symptoms of hypo/hyperglycemia and notify their healthcare practitioner if seen.