comes among women treated with glyburide. First, like metfor min, glyburide crosses the placenta and reaches concentrations in the fetus that are more than two thirds of maternal lev els (Caritis, 2013). Additionally, a study of more than 9000 women with gestational diabetes treated with either insulin or glyburide showed a signiicant rise in rates of neonatal intensive care unit admission, respiratory distress, and neonatal hypogly cemia associated with glyburide use (Castillo, 2015).
Metformin reaches fetal serum concentrations similar to maternal levels. However, in one study of 751 women with gestational diabetes who were randomly assigned to metformin or insulin treatment, short-term perinatal adverse events did not difer between groups (Rowan, 2008). Outcomes included neonatal hypoglycemia, respiratory distress syndrome, photo therapy, birth trauma, 5-minute Apgar score .7, and preterm birth. Overall growth of ofspring at age 2 years also did not difer (Rowan, 2011). Nevertheless, the fat distribution in chil dren exposed to metformin showed a tendency toward a more favorable pattern. From a smaller randomized metformin trial, at 18 months, ofspring exposed to metformin were slightly heavier, but markers of early motor or language development did not difer compared with those in ofspring exposed to insulin (Ijas, 2015).
The Food and Drug Administration has not approved glyburide and metformin use for treatment of gestational diabetes. However, the American College of Obstetricians and Gynecologists (2017 a) recognizes both as reasonable choices for second-line glycemic control in women with gestational diabetes. Because long-term outcomes have not been fully studied, the committee recommends appropriate counseling, which includes disclosing the limitations in current safety data.
In general, for women with gestational diabetes who do not require insulin, early delivery or other interventions are seldom required. here is no consensus regarding the value or timing of antepartum fetal testing. It is typically reserved for women with pregestational diabetes because of the greater stillbirth risk. The American College of Obstetricians and Gynecologists (2017a) endorses fetal surveillance in women with gestational diabetes and poor glycemic control. At Parkland Hospital, women with gestational diabetes are routinely instructed to perform daily fetal kick counts in the third trimester (Chap. 17, p. 332). Insulin-treated women are ofered inpatient admission after 34 weeks' gestation, and antepartum monitoring is performed three times each week.
Women with gestational diabetes and adequate glycemic control are managed expectantly. Elective labor induction to prevent shoulder dystocia compared with spontaneous labor remains controversial. Alberico and colleagues (2017) recently described their truncated randomized trial of 425 women with tation. Although underpowered, this GINEXMAL Trial dem onstrated no clinically meaningful diference in the cesarean delivery rate between the induction and expectant management groups-12.6 versus 11.8 percent. However, with early labor induction, neonatal hyperbilirubinemia rates were signiicantly higher, and ironically, there was a nonsigniicant threefold greater shoulder dystocia rate. In a retrospective cohort study of 8392 Canadian women with gestational diabetes, Melamed 39 weeks was associated with a lower rate of cesarean delivery but with an elevated rate of neonatal intensive care unit admis sion. The American College of Obstetricians and Gynecologists 39 weeks' gestation. At Parkland Hospital, women with diet treated gestational diabetes are not electively induced for this indication. However, those treated with insulin are delivered at 38 weeks' gestation.