gynecology and obstetrics
Diabetes Mellitus in Pregnancy
Treatment of Diabetes Mellitus in Pregnancy
Close monitoring Tight control of blood glucose Management of complications Preconception counseling and optimal control of diabetes before, during, and after pregnancy minimize maternal and fetal risks, including congenital malformations ( Treatment references ). Because malformations may develop before pregnancy is diagnosed, the need for constant, strict control of glucose levels is stressed to women who have diabetes and who are considering pregnancy (or who are not using contraception). To minimize risks, clinicians should do all of the following: Involve a diabetes team (eg, physicians, nurses, nutritionists, social workers) and a pediatrician Promptly diagnose and treat complications of pregnancy, no matter how trivial Plan for delivery and have an experienced pediatrician present Ensure that neonatal intensive care is available In regional perinatal centers, specialists in management of diabetic complications are available. Treatment can vary, but some general management guidelines are useful (see tables,, and). Women with type 1 or 2 should monitor their blood glucose levels at home. During pregnancy, normal fasting blood glucose levels are about 76 mg/dL (4.2 mmol/L). Goals of treatment are Fasting blood glucose levels at < 95 mg/dL (< 5.3 mmol/L) 2-hour postprandial levels at ≤ 120 mg/dL (≤ 6.6 mmol/L) No wide blood glucose fluctuations Glycosylated hemoglobin (HbA1c) levels at < 6.5% Insulinis the traditional treatment of choice because it cannot cross the placenta and provides more predictable glucose control; it is used for types 1 and 2 diabetes and for some women with gestational diabetes. Humaninsulinis used if possible because it minimizes antibody formation.Insulinantibodies cross the placenta, but their effect on the fetus is unknown. In some women with long-standing type 1 diabetes, hypoglycemia does not trigger the normal release of counterregulatory hormones (catecholamines,glucagon, cortisol, and growth hormone); thus, too muchinsulincan trigger hypoglycemic coma without premonitory symptoms. All pregnant women with type 1 should haveglucagonkits and be instructed (as should family members) in givingglucagonif severe hypoglycemia (indicated by unconsciousness, confusion, or blood glucose levels<40 mg/dL [<2.2 mmol/L]) occurs. All pregnant women with type 1 diabetes should haveglucagonkits and be instructed (as should their family members) in givingglucagonif severe hypoglycemia occurs. Oral hypoglycemic drugs(eg,metformin) are being increasingly used to manage diabetes in pregnant women because of the ease of administration (pills compared to injections), low cost, and single daily dosing. Several studies have shown thatmetforminis safe during pregnancy and that it provides control equivalent to that ofinsulinfor women with gestational diabetes. For women with type 2 diabetes before pregnancy, data for use of oral drugs during pregnancy are scant;insulinis most often preferred. Oral hypoglycemics taken during pregnancy may be continued postpartum during breastfeeding, but the infant should be closely monitored for signs of hypoglycemia. Although diabetic retinopathy, nephropathy, and mild neuropathy are not contraindications to pregnancy, they require preconception counseling and close management before and during pregnancy. Retinopathyrequires that an ophthalmologic examination be done every trimester. If proliferative retinopathy is noted at the first prenatal visit, photocoagulation should be used as soon as possible to prevent progressive deterioration. Nephropathy,particularly in women with renal transplants, predisposes to gestational hypertension. Risk of preterm delivery is higher if maternal renal function is impaired or if transplantation was recent. Prognosis is best if delivery occurs≥2 years after transplantation. 8.5% during the 1st trimester, risk of congenital malformations is significantly increased, and targeted ultrasonography and fetal echocardiography are done during the 2nd trimester to check for malformations ( Treatment references ). If women with type 2 diabetes take oral hypoglycemic drugs during the 1st trimester, fetal risk of congenital malformations is unknown (see table Certain precautions are required to ensure an optimal outcome. depends on fetal well-being. Women are told to count fetal movements during a 60-minute period daily (fetal kick count) and to report any sudden decreases to the obstetrician immediately. Fetal Monitoring is begun at 32 weeks; it is done earlier if women have severe hypertension or a renal disorder or if fetal growth restriction is suspected. Amniocentesis to assess fetal lung maturity may be necessary for women with the following: Obstetric complications in past pregnancies Inadequate prenatal care Uncertain delivery date Poor glucose control Poor adherence to therapy Type of deliveryis usually spontaneous vaginal delivery at term. Risk of stillbirth and shoulder dystocia increases near term. Thus, if labor does not begin spontaneously by 39 weeks, induction is often necessary. Dysfunctional labor, fetopelvic disproportion, or risk of shoulder dystocia may make cesarean delivery necessary. Blood glucose levelsare best controlled during labor and delivery by a continuous low-doseinsulininfusion. If induction is planned, women eat their usual diet the day before and take their usualinsulindose. On the morning of labor induction, breakfast andinsulinare withheld, baseline fasting plasma glucose is measured, and an IV infusion of 5%dextrosein 0.45% saline solution is started at 125 mL/hour, using an infusion pump. Initialinsulininfusion rate is determined by capillary glucose level.Insulindose is determined as follows: Initially: 0 units for a capillary level of<80 mg/dL (<4.4 mmol/L) or 0.5 units/hour for a level of 80 to 100 mg/dL (4.4 to 5.5 mmol/L) Thereafter: Increased by 0.5 units/hour for each 40-mg/dL (2.2-mmol/L) increase in glucose level over 100 mg/dL up to 2.5 units/hour for levels>220 mg/dL (>12.2 mmol/L) Every hour during labor: Measurement of glucose level at bedside and adjustment of dose to keep the level at 70 to 120 mg/dL (3.8 to 6.6 mmol/L) If the glucose level is significantly elevated: Possibly additional bolus doses For spontaneous labor, the procedure is the same, except that if intermediate-actinginsulinwas taken in the previous 12 hours, theinsulindose is decreased. For women who have fever, infection, or other complications and for women with obesity who have type 2 and have required>100 units ofinsulin/day before pregnancy, theinsulindose is increased. After delivery, loss of the placenta, which synthesizes large amounts ofinsulinantagonist hormones throughout pregnancy, decreases theinsulinrequirement immediately. Thus, women with gestational diabetes and many of those with type 2 require noinsulinpostpartum. For women with type 1,insulinrequirements decrease dramatically but then gradually increase after about 72 hours. During the first 6 weeks postpartum, the goal is tight glucose control. Glucose levels are checked before meals and at bedtime. Breastfeeding is not contraindicated but may result in neonatal hypoglycemia if oral hypoglycemics are taken. Women who have had gestational diabetes should have a 2-hour oral glucose tolerance test with 75 g of glucose at 6 to 12 weeks postpartum to determine whether diabetes has resolved. 1.American College of Obstetricians and Gynecologists' Committee on Practice Bulletins—Obstetrics. ACOG Practice Bulletin No. 201: Pregestational Diabetes Mellitus.Obstet Gynecol132(6):e228-e248, 2018. doi:10.1097/AOG.0000000000002960 2.Miller E, Hare JW, Cloherty JP, et al: Elevated maternal hemaglogin A1c in early pregnancy and major congenital anomalies in infants of diabetic mothers.N Engl J Med304 (22):1331–1334, 1981. doi: 10.1056/NEJM198105283042204 