Hyperglycemia, or high blood sugar, is one sign of diabetes. Hyperglycemia in pregnancy can affect women with pre-existing Type 1 or Type 2 diabetes, or can develop during the pregnancy. Hyperglycemia that develops during pregnancy, known as gestational diabetes, affects around 1 to 3 percent of pregnancies overall, says the Merck Manual. Hyperglycemia from any cause can seriously affect both mother and baby and increases the risk of complications during pregnancy, labor and after delivery.
The risk of birth defects isn’t increased in women with gestational diabetes, but women who have high glucose levels in the first weeks of pregnancy due to pre-existing diabetes have a risk three to four times higher than normal of having a baby with birth defects, the Eastern Virginia School of Medicine Maternal Fetal Health Division warns. Birth defects from hyperglycemia in the first trimester most often affect the developing brain, heart and spinal cord, the same source states.
Macrosomia, defined as birthweight greater than 8.8 pounds in a full-term infant or an infant whose weight falls above the 90th percentile, occurs in 25 to 45 percent of women with hyperglycemia from diabetes, Mary Elaine Patrinos, MD of the University of Hawaii John A. Burns School of Medicine reports. Macrosomia, which occurs as a result of elevated glucose and insulin levels in the fetus due to maternal hyperglycemia, leads to increased Cesarean section rates in mothers with diabetes and increases the risk of shoulder dystocia, difficulty delivering the fetal shoulders once the head delivers. Shoulder dystocia can cause injury to the nerves in the baby’s arms or shoulders, leading to permanent disability.
Babies whose mothers have hyperglycemia have high levels of glucose in their blood as well, because of high circulating glucose levels through the placenta. Before birth, they produce more insulin than normal to absorb the larger than normal glucose levels. After delivery, their glucose levels abruptly drop as the glucose source disappears, but they continue to produce large amounts of insulin, which absorbs too much glucose from the bloodstream. Blood sugar levels drop abruptly, causing hypoglycemia in infants of hyperglycemic mothers.
The baby may be jittery, unable to maintain body temperature, have breathing difficulties, feed poorly and can develop seizures or brain damage if hypoglycemia isn’t rapidly diagnosed, according to MedlinePlus. Early feeding of glucose solutions and frequent monitoring of blood glucose levels treats hypoglycemia in newborns.
Stillbirth, or death of the fetus before delivery, occurs more often in mothers whose hyperglycemia is caused by pre-existing Type 1 or 2 diabetes, the Eastern Virginia School of Medicine states. Hyperglycemia damages blood vessels in the placenta, resulting in decreased nutrition and oxygen transport to the fetus. Close monitoring of fetal well being and delivery by 38 to 40 weeks of pregnancy helps decrease the risk of stillbirth, the Merck Manual explains.