Women with pregestational diabetes are at an increased risk for congenital malformations and pregnancy complications more than women without this condition. The most common malformations seen include cardiac defects, spinal bifida, and cleft lip and/or palate. Women with pregestational diabetes are also at risk for other complications, including miscarriage, fetal growth, preeclampsia, stillbirth, cesarean delivery, birth trauma, and neonatal hypoglycemia and electrolyte abnormalities.
Glycemic Control for Women with Pregestational Diabetes during Pregnancy
To decrease these risks, proper glycemic control is recommended:
- Goals – For most patients, the target blood glucose values are fasting glucoses less than 90 mg/dl, one hour postprandial values less than 130-140 mg/dl, and two hour values less than 120 mg/dl.
- Diet – Women with pregestational diabetes are encouraged to replace refined carbohydrates with complex carbohydrates, with carbohydrates making up between 40 to 50% of the daily caloric intake. For many patients, formal nutritional counseling and follow-up appointments are beneficial in achieving euglycemia via diet alone, or reducing the requirements for pharmacologic intervention.
- Exercise – An increase in activity and exercise has shown to help achieve euglycemia more than just diet alone.
- Medication – In some cases, women may require medication to reach euglycemia. Both glyburide and metformin are safe and effective medications for pregnant women with diabetes. If these are unsuccessful, insulin is the main treatment for proper glycemic control.
Testing for Women with Pregestational Diabetes
We suggest a baseline assessment of renal function with a 24-hour urine collection. Additionally, we recommend an ophthalmologic examination. Also, due to an increased risk of congenital anomalies, we recommend anatomical surveys at 16 to 20 weeks and a fetal echocardiography at 20 weeks’ gestation is advised. Serial growth ultrasounds are recommended every four weeks and weekly biophysical profiles can be begin at 32 weeks, or earlier if indicated, such as in the setting of fetal growth restriction.
Delivery and Pregestational Diabetes
Women with pregestational diabetes should deliver by 39 to 40 weeks, or sooner if there is poor glycemic control or other pregnancy complications.
Macrosomia, or an estimated fetal weight (EFW) of more than 4,000g, is more likely to occur in diabetic women. Complications associated with macrosomia include prolonged labor, oxytocin requirement, shoulder dystocia (birth injury), cesarean delivery, postpartum hemorrhage, and increased rate of vaginal lacerations during delivery. Cesarean delivery is recommended if an EFW is more than 4,500g in a diabetic woman, or based on other clinical indications.
Reduce the Risk of Preeclampsia
A meta-analysis of 14 studies with data from over 12,000 high-risk pregnant women, including diabetics, demonstrated that low dose aspirin reduces the risk of preeclampsia, preterm birth and perinatal death. While there is no consensus on aspirin use during pregnancy, we advise our patients at a high risk for preeclampsia to take 81mg of aspirin daily.
Overall, with careful attention to glycemic control as well as close fetal monitoring, most women with diabetes can achieve successful pregnancies.
Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!