Anwar Nassar, MD
Professor of Obstetrics and Gynecology
Interim Chairman, AUBMC
Most cases of diabetes in pregnancy (90%) are gestational diabetes (GD), which begins or is first recognized during pregnancy. The remaining are patients diagnosed with diabetes before pregnancy. Tight blood sugar control during pregnancy is the key for an optimal pregnancy outcome in either type of diabetes since poor blood sugar control can have serious short- and long-term consequences for both the mother and the baby.
GD affects ~7% of expectant mothers, making it one of the most common health problems of pregnancy. For few moms-to-be, the pancreas can’t keep up with the increased insulin demand during pregnancy, and therefore blood glucose levels rise too high, resulting in GD, which usually has no symptoms. That’s why pregnant women are usually screened for diabetes at 24-28 weeks. In those at high risk for diabetes (obese, GD in a previous pregnancy, family history of diabetes and sugar in their urine test), screening is done at the 1st prenatal visit and repeated at 24-28 weeks. If the screening test is positive, a confirmatory test is then performed. Most women with GD go on to have healthy babies. Dietary changes and exercise may be enough to keep the blood sugar levels under control, but sometimes medications are needed. Artificial sweeteners may be safely used in moderate amounts. Complications of uncontrolled GD include overly large babies where the baby’s shoulders may get stuck during delivery. This can result in a fractured bone or nerve damage, both of which heal without permanent problems in the majority of babies. That is why some doctors may recommend that women with suspected large babies give birth by cesarean section. Shortly after birth, some babies may have low blood sugar (hypoglycemia), jaundice, polycythemia (an increase in the number of red cells in the blood), hypocalcemia (low calcium in the blood), breathing problems at birth (the lungs of babies whose mothers have diabetes tend to mature a bit later) and even stillbirth (death of baby before delivery) in the last two months of pregnancy. Finally, women with GD are at increased risk for developing preeclampsia, a disease characterized by high blood pressure and edema. GD goes away after birth, but it does increase the risk of a woman for developing diabetes later in life. One third of women who had GD will continue to have diabetes.
For women diagnosed with diabetes before pregnancy, medical help should be sought before getting pregnant. This preconception visit is essential since high dose folic acid should be started and tight blood sugar control (glycosylated hemoglobin levels Hb A1C <6.1%) should be ensured before pregnancy. Women with pregestational diabetes are at increased risk of abortion, polyhydramnios (excessive amniotic fluid), birth defects, stillbirth, and several complications in their babies like hypoglycemia, respiratory problems, growth restriction (low birth weights), hypoglycemia, hypomagnesemia, polycythemia, hyperbilirubinemia (high bilirubin levels), and increased risk for the baby of inheriting diabetes. Women are at increased risk of delivering by cesarean and of having preterm labor and preeclampsia. To help reduce these risks, the patient should follow a meal plan and a liberal exercise program and should test blood sugar and take her medications, usually insulin and more recently oral hypoglycemics. She will have to come for more frequent prenatal visits than the usual. The recommended daily caloric intake is 30 kcal/kg and may be distributed as: 10–20% at break- fast; 20–30% at lunch; 30–40% at dinner; and up to 30% for snacks, especially a bedtime snack to reduce hypoglycemia at night. The goals of blood sugar control are 60-90 mg/dl before breakfast and 120 mg/dl 2 hours after meals. In case of hypoglycemia, a glass of milk is preferable to fruit juices containing high levels of glucose. A fetal ultrasound and echo-cardiogram (an ultrasound that focuses on the baby’s heart) are usually ordered because the risk of birth defects, especially heart defects. Other tests include: fetal heart monitoring (non-stress tests) to check for his well-being and one or more ultrasounds during 3rd trimester to monitor baby’s growth.
Nowadays, with adequate follow up and tight blood sugar control, favorable pregnancy outcomes can be attained in women with pre-gestational and gestational diabetes.