Increased blood sugars 4-6 h prior to delivery leads to increased rates of hypoglycemia in the neonate. A maternal blood glucose value of more than 180 mg/dl has been conclusively proven to be associated with high risk of neonatal hypoglycemia.

The American College of Obstetrics and Gynecology and the American College of Endocrinology recommends maintenance of blood glucose between 70 and 110 mg/dl during labor (3.9-6.1 mmol/L) this goal is the same irrespective of whether the women has type 1 diabetes, type 2 diabetes or GDM.

The hepatic glucose supply is sufficient during the latent phase of labor, but during the active phase of labor the hepatic glucose supply is depleted so calorie supplementation is required.

During labor in a case with GDM controlled only on life-style modification, it is not compulsory to monitor blood sugars periodically and monitoring once in every 4-6 h is sufficient during labor

In patients on insulin it is mandatory to monitor the blood sugar every 2-4 h during the latent phase, every 1-2 h during the active phase

In patients for whom cesarean is planned, it always preferred to do the procedure early morning.

Patient needs to take her usual night dose of intermediate-acting insulin and the morning dose of insulin has to be withheld and patient needs to be kept nil by mouth.

If surgery is delayed it is needed to start basal and corrective regimen (DNS with short acting insulin) with one-third of the morning intermediate insulin dose with a 5% dextrose infusion to avoid ketosis. Blood glucose has to be monitored second hourly and if required subcutaneous dose of corrective dose of short acting insulin to be given.

After delivery, the requirement of insulin shows a sharp decline and in GDM it is advisable to continue the monitoring to see if the sugars have become normal in the postpartum period

In cases with type 1 and type 2 DM it is prudent to decrease the dose of insulin by 20-40% of the pregnancy dose as the requirement of insulin during lactation is less. During the breast-feeding, sometimes the requirement of insulin can fall drastically and these women may develop hypoglycemia, so the dose of insulin needs to be adjusted accordingly

Reference: ACOG Practice Bulletin, 137, 2013

Indian Journal of Endocrinology and Metabolism: Peripartum management of diabetes, Pramila Kalra and Manjunath Anakal