The increased risk for adverse maternal and neonatal outcomes in pregnant women with preexisting diabetes — such as preeclampsia, cesarean delivery, and macrosomia — can be mitigated with optimization of glycemic control, appropriate medication regimens, and the use of a multidisciplinary team, according to research published in JAMA.
Approximately 0.9% of all births in the United States annually are complicated by preexisting diabetes, with both type 1 and type 2 diabetes requiring a similar intensity of care. To determine comprehensive diabetes care during pregnancy, researchers searched the PubMed database from January 1, 2000, to January 31, 2019, for studies on the management of preexisting diabetes in pregnancy.
One of the most important steps in reducing the risk for birth defects in children of women with preexisting diabetes is appropriate prepregnancy planning. Hemoglobin A1c levels should be ˂6.5% at conception and ˂6.0% throughout pregnancy. Prior to conception, women with diabetes should be referred to a maternal-fetal medicine specialist for counseling and intensified fetal surveillance during pregnancy.
Efforts should be made to optimize weight and glycemic control prior to conception; therefore, all women with diabetes should be referred to a dietician prior to or early in pregnancy. Women who have a body mass index >40 kg/m2 should be screened for obstructive sleep apnea, as this comorbidity may be linked with higher rates of gestational hypertension, preeclampsia, and preterm birth.
Women should be screened for complications of diabetes such as retinopathy and nephropathy. Women with both chronic hypertension and diabetes should aim for a target systolic blood pressure of 120 mm Hg and a diastolic blood pressure of 80 to 100 mm Hg. Medications such as angiotensin-converting enzyme inhibitors and statins should be discontinued as they are known to be unsafe in pregnancy. Because diabetes in pregnancy increases the risk for preeclampsia, initiation of low-dose aspirin is recommended between 12 and 28 weeks of gestation.
For women with type 1 diabetes who plan to become pregnant, thyroid-stimulating hormone levels should be checked.
Insulin is the first-line therapy for all pregnant women with preexisting diabetes — regardless of type — and close glucose monitoring is necessary, as insulin requirements may increase throughout pregnancy. Multiple daily injections as well as insulin pump therapy are both effective approaches for insulin management. Oral agents are not recommended for pregnant women with type 2 diabetes because these medications are not able to overcome the increased insulin resistance of pregnancy, and drugs such as metformin and sulfonylureas cross into the placenta, whereas insulin does not. Newer glucose-lowering agents such as dipeptidyl pepridase-4 inhibitors are not recommended in pregnancy.
Women receiving multiple daily injections of insulin are advised to monitor capillary glucose level during fasting, preprandial, and postprandial states and to undergo at least 7 glucose checks daily; recommended targets are <95 mg/dL for fasting glucose level, <140mg/dL for 1-hour postprandial glucose level, and <120 mg/dL for 2-hour postprandial glucose level. Close glucose monitoring is essential to avoid hypoglycemia, which can lead to low birth weight.
Women who are pregnant or plan to become pregnant should be educated regarding diabetic ketoacidosis, as pregnancy promotes insulin resistance, accelerated lipolysis, and a surplus of free fatty acids. To prevent diabetic ketoacidosis, women are advised to consume an adequate amount of carbohydrates.
Women with preexisting diabetes should breastfeed to facilitate weight loss and maternal-infant bonding and lower the risk for obesity and type 2 diabetes in offspring. Long-acting, reversible contraceptive use is safe in the postpartum period and does not affect glycemic control, breastfeeding, or infant growth negatively.
Alexopoulos, AS, Blair R, Peters AL. Management of preexisting diabetes in pregnancy: a review. JAMA. 2019;321(18):1811-1819.