The growing rates of obesity in the United States and around the world have increased the incidences of diabetes during gestation.
Women who are overweight or obese at the beginning of pregnancy are at a greater risk for the development of diabetes during pregnancy.
However, women with a healthy BMI (body mass index) can also be affected.
The increased chances of developing Gestational Diabetes Mellitus (GDM) comes partly from the physiology of pregnancy itself. On average sensitivity to insulin decreases about 60% during pregnancy, this is partly due to the presence of the hormone human placental lactogen (hPL). hPL has been known to interfere with susceptible insulin receptors which lead to decreased sensitivity and while promoting glycolysis.
Elevated blood sugar levels (hyperglycemia) is more common in later pregnancy, during the third trimester, and it can lead to adverse outcomes for both the mother and child during the perinatal period.
Effects on Mother:
Women with pregestational diabetes, either type 1 or type 2, need to be monitored and treated before and throughout pregnancy. Diabetes during pregnancy, whether pregestational or gestational, puts the mother at increased risk for the development of heart disease and infections.
Risks also include maternal gestational hypertension, preeclampsia, eclampsia, and increased chances for cesarean delivery. Birth complications like postpartum hemorrhages are also more common in women with GDM and there is an increased chance of injuring the child at birth.
Women with a healthy BMI (body mass index) can also be affected.
Effects on Fetus:
GDM also comes with increased risks for the fetus in both development and delivery. The hyperglycemic environment in the mother can lead to an increased insulin response by the fetus, as a result, neonatal hypoglycemia (low blood sugar) is a common risk at delivery. Once the fetus exits the hyperglycemic environment of the mother, the elevated insulin levels can lead to a sudden drop in blood sugar.
Fetal macrosomia, a fetus with above normal weight, is also common due to the increased delivery of glucose and growth factors during pregnancy. Increased fetal size, in turn, puts the fetus at increased risk for injury at birth. Shoulder dystocia can occur as a result of fetal size, this is when the fetus’s shoulder gets stuck under the pubic symphysis during delivery.
The HAPO Study
A large study was carried out called the Hyperglycemia and Adverse Pregnancy Outcome Study (HAPO Study), the goal was to study the related risks that come with various levels hyperglycemia during pregnancy.
The results showed no clear threshold in which glucose levels become excessively harmful, however, there is a clear increased frequency of cesarean deliveries, fetal macrosomia, and neonatal hypoglycemia observed with rising maternal glucose levels.
Prevention and Treatment
Women who enter pregnancy with already developed type 1 or type 2 diabetes must be monitored throughout pregnancy to control for adverse outcomes early on. Obese or overweight women who plan on being pregnant should consult a physician and undergo lifestyle changes to reduce BMI in a healthy manner.
Nutrition counseling and lifestyle control are often enough to control hyperglycemia and prevent associated complications. In certain cases, however, in which lifestyle control and nutrition guidelines are not enough, safe drugs can be administered by a licensed professional.