Diabetes and pregnancy: Risks and opportunities

GET GLUCOSE UNDER CONTROL BEFORE PREGNANCY

Hyperglycemia (Table 1^12,13) during the periconception period or during pregnancy is believed to be the single most important determinant of adverse outcomes in women with diabetes.¹⁴ Thus, glycemic control is crucial, aiming for levels as close to normal as possible while avoiding hypoglycemia. A hemoglobin A_1c level below 6.5% reduces the risk of congenital anomalies, especially anencephaly, microcephaly, congenital heart disease, and caudal regression.¹

Nearly half of pregnancies in the general population are unplanned,¹⁵ so preconception diabetes assessment needs to be part of routine medical care for all reproductive-age women. Because most organogenesis occurs during the first 5 to 8 weeks after fertilization—potentially before a woman realizes she is pregnant—achieving optimal glycemic control before conception is necessary to improve pregnancy outcomes.¹

EVERY VISIT IS AN OPPORTUNITY

Every medical visit with a reproductive-age woman with diabetes is an opportunity for counseling about pregnancy. Topics that need to be discussed include the risks of unplanned pregnancy and of poor metabolic control, and the benefits of improved maternal and fetal outcomes with appropriate pregnancy planning and diabetes management.

Referral to a registered dietitian for individualized counseling about proper nutrition, particularly during pregnancy, has been associated with positive outcomes.¹⁶ Patients with diabetes and at high risk of pregnancy complications should be referred to a clinic that specializes in high-risk pregnancies.

Practitioners also should emphasize the importance of regular exercise and encourage patients to maintain or achieve a medically optimal weight before conception. Ideally, this would be a normal body mass index; however, this is not always possible.

In women who are planning pregnancy or are not on effective contraception, medications should be reviewed for potential teratogenicity. If needed, discuss alternative medications or switch to safer ones. However, these changes should not interrupt diabetes treatment.

In addition, ensure that the patient is up to date on age- and disease-appropriate preventive care (eg, immunizations, screening for sexually transmitted disease and malignancy). Counseling and intervention for use of tobacco, alcohol, and recreational drugs are also important. As with any preconception counseling, the patient (and her partner, if possible) should be advised to avoid travel to areas where Zika virus is endemic, and informed about the availability of expanded carrier genetic screening through her obstetric provider.

Glycemic control should be assessed during every visit and adjustments made to maintain or achieve optimal glycemic control (Table 2) to prevent progression of diabetes and to improve obstetric and neonatal outcomes.

Finally, pregnant women with diabetes benefit from screening for diabetic complications including hypertension, retinopathy, cardiovascular disease, neuropathy, and nephropathy.

ASSESSING RISKS

Blood pressure

Chronic (preexisting) hypertension is defined as a systolic pressure 140 mm Hg or higher or a diastolic pressure 90 mm Hg or higher, or both, that antedates pregnancy or is present before the 20th week of pregnancy.³ Chronic hypertension has been reported in up to 5% of pregnant women and is associated with increased risk of preterm delivery, superimposed preeclampsia, low birth weight, and perinatal death.³

Reproductive-age women with diabetes and high blood pressure benefit from lifestyle and behavioral modifications.¹⁷ If drug therapy is needed, antihypertensive drugs that are safe for the fetus should be used. Treatment of mild or moderate hypertension during pregnancy reduces the risk of progression to severe hypertension but may not improve obstetric outcomes.

Diabetic retinopathy

Diabetic retinopathy can significantly worsen during pregnancy: the risk of progression is double that in the nonpregnant state.¹⁸ Women with diabetes who are contemplating pregnancy should have a comprehensive eye examination before conception, and any active proliferative retinopathy needs to be treated. These patients may require ophthalmologic monitoring and treatment during pregnancy. (Note: laser photocoagulation is not contraindicated during pregnancy.)

Cardiovascular disease

Cardiovascular physiology changes dramatically during pregnancy. Cardiovascular disease, especially when superimposed on diabetes, can increase the risk of maternal death. Thus, evaluation for cardiovascular risk factors as well as cardiovascular system integrity before conception is important. Listen for arterial bruits and murmurs, and assess peripheral pulses. Consideration should be given to obtaining a preconception resting electrocardiogram in women with diabetes who are over age 35 or who are suspected of having cardiovascular disease.¹⁶

Neurologic disorders

Peripheral neuropathy, the most common neurologic complication of diabetes, is associated with injury and infection.¹⁹

Autonomic neuropathy is associated with decreased cardiac responsiveness and orthostatic hypotension.¹⁹ Diabetic gastroparesis alone can precipitate serious complications during pregnancy, including extreme hypoglycemia and hyperglycemia, increased risk of diabetic ketoacidosis, weight loss, malnutrition, frequent hospitalizations, and increased requirement for parenteral nutrition.²⁰

Although diabetic neuropathy does not significantly worsen during pregnancy, women with preexisting gastroparesis should be counseled on the substantial risks associated with pregnancy. Screening for neuropathy should be part of all diabetic preconception examinations.

Renal complications

Pregnancy in women with diabetes and preexisting renal dysfunction increases their risk of accelerated progression of diabetic kidney disease.²¹ Preexisting renal dysfunction also increases the risk of pregnancy-related complications, such as stillbirth, intrauterine growth restriction, gestational hypertension, preeclampsia, and preterm delivery.^19,21,22 Further, the risk of pregnancy complications correlates directly with the severity of renal dysfunction.²²

Psychiatric disorders

Emotional wellness is essential for optimal diabetes management. It is important to recognize the emotional impact of diabetes in pregnant women and to conduct routine screening for depression, anxiety, stress, and eating disorders.¹⁶