Case 1 A 32-year-old obese woman with type 2 diabetes mellitus (T2DM) presents for routine follow-up. Recent lab results reveal an A1C of 6.4%; GFR > 100 mL/min/1.73 m2; and microalbuminuria (110 mg/d). She is currently taking lisinopril (2.5 mg once daily), metformin (1,000 mg bid), and glyburide (5 mg bid). She plans to become pregnant in the next six months and wants advice.
Discussion
This patient should be counseled on preconception glycemic targets and switched to pregnancy-safe medications. She should also be advised that the recommended weight gain in pregnancy for women with T2DM is 15 to 25 lb in overweight women and 10 to 20 lb in obese women.3
The ADA recommends a target A1C < 7%, in the absence of severe hypoglycemia, prior to conception in patients with type 1 diabetes mellitus (T1DM) or T2DM.3 For women with preconception diabetes who become pregnant, it is recommended that their premeal, bedtime, and overnight glucose be maintained at 60 to 99 mg/dL, their peak postprandial glucose at 100 to 129 mg/dL, and their A1C < 6% during pregnancy (all without excessive hypoglycemia), due to increases in red blood cell turnover.3 It is also recommended that they avoid statins, ACE inhibitors, angiotensin II receptor blockers (ARBs), certain beta blockers, and most noninsulin therapies.3
This patient is currently taking lisinopril, a medication with a pregnancy category of X. The ACE inhibitor class of medications is known to cause oligohydramnios, intrauterine growth retardation, structural malformation, premature birth, fetal renal dysplasia, and other congenital abnormalities, and use of these drugs should be avoided in women trying to conceive.7
Safer options for blood pressure control include clonidine, diltiazam, labetalol, methyldopa, or prazosin.3 Diuretics can reduce placental blood perfusion and should be avoided.8 An alternative for management of microalbuminuria in women of childbearing age is nifedipine.9 In multiple studies, this medication was not only safer in pregnancy, with no major teratogenic risk, but also effectively reduced urine microalbumin levels.10,11
For T2DM management, metformin (pregnancy category B) and glyburide (pregnancy category B/C, depending on manufacturer) can be used.12,13 Glyburide, the most studied sulfonylurea, is recommended as the drug of choice in its class.14-16 While insulin is the standard for managing diabetes in pregnancy—earlier research supported a switch from oral medications to insulin in women interested in becoming pregnant—recent studies have demonstrated that oral medications can be safely used.17 In addition, lifestyle changes (eg, carbohydrate counting, limited meal portions, and regular moderate exercise) prior to and during pregnancy can be beneficial for diabetes management.18,19
Also remind the patient to take regular prenatal vitamins. The US Preventive Services Task Force recommends that all women planning to become or capable of becoming pregnant take 400 to 800 µg supplements of folic acid daily.20 For women at high risk for neural tube defects or who have had a previous pregnancy with neural tube defects, 4 mg/d is recommended.21 In women with diabetes who are trying to conceive, a folic acid supplement of 5 mg/d is recommended, beginning three months prior to conception.22
Research shows that diabetic women are less likely to take folic acid supplementation during pregnancy. A study of 6,835 obese or overweight women with diabetes showed that only 35% reported daily folic acid supplementation.23 The study authors recommended all women of childbearing age, especially those who are obese or have diabetes, take folic acid daily.23 Encourage all women intending to become pregnant to start prenatal vitamin supplementation.
Continue for case 2 >>