An earlier retrospective study followed 97 pregnant patients with gestational diabetes, 69 of whom were diet-controlled (class A1, fasting glucose <105 mg/dL).5 Antepartum surveillance consisted of maternal monitoring and non-stress testing. At 28 weeks, pregnant patients assessed daily fetal activity; reassuring fetal well-being was defined as 10 fetal movements in a 12-hour period. At 40 weeks, a non-stress test was performed weekly. Contraction stress testing was performed for those with nonreactive non-stress tests. To observe for macrosomia, serial ultrasonography was performed every 4 to 6 weeks, starting at 28 weeks. Forty-four patients (64%) had spontaneous labors without intervention, while the rest required induction of labor or cesarean section (primary or failed induction). Five patients had primary cesarean section for suspected macrosomia, 3 patients had intervention for suspected intrauterine growth restriction, and only 4 (5.7%) patients were delivered due to fetal indications, defined as decreased fetal movement or a nonreactive nonstress test. No stillbirths or neonatal deaths occurred. Perinatal complications included hypoglycemia (n=13; 19%), hyperbilirubinemia (n=12; 17%), and macrosomia (n=11; 16%). The study did not compare complication rates between diet-controlled and insulin-requiring patients (SOR: B, retrospective study).
A Cochrane review found no evidence for or against increased surveillance in A1 gestational diabetes: “A lack of conclusive evidence has lead clinicians to equate the risk of adverse perinatal outcome with pre-existing diabetes. Consequently women are often managed with increased obstetrical monitoring, dietary regulation, and [pharmacological] treatment. However, no sound evidence base supports such intensive treatment.”6
TABLE
At least 2 of 4 measurements over 3 hours must be higher than these values to diagnose gestational diabetes mellitus
| STATUS | PLASMA OR SERUM GLUCOSE LEVEL (CARPENTER/COUSTAN CONVERSION AMERICAN DIABETES ASSOCIATION)1 | PLASMA LEVEL DATA (NATIONAL DIABETES GROUP CONVERSION AMERICAN COLLEGE OF OB/GYN)2 | ||
|---|---|---|---|---|
| MG/DL | MMOL/L | MG/DL | MMOL/L | |
| Fasting | 95 | 5.3 | 105 | 5.8 |
| 1 hour | 180 | 10.0 | 190 | 10.6 |
| 2 hours | 155 | 8.6 | 165 | 9.2 |
| 3 hours | 140 | 7.8 | 145 | 8.0 |
TABLE
White’s classification for gestational diabetes mellitus
| CLASS | DEFINITION |
|---|---|
| A1 | Diabetes diagnosed during pregnancy; non-insulin-dependent |
| A2 | Diabetes diagnosed during pregnancy; insulin-dependent |
| B | Diabetes diagnosed after age 20 years or duration less than 10 years; no vascular complications |
| C | Diabetes diagnosed between age 10 to 19 years or duration of 10 to 19 years; no vascular complications |
| D | Diabetes diagnosed before age of 10 years or duration greater than 20 years; vascular complications present |
| F | Diabetes with nephropathy |
| H | Diabetes with coronary artery or other heart disease |
| R | Diabetes with retinopathy |
| T | Diabetes status post–renal transplant |
Recommendations from others
The American College of Obstetricians and Gynecologists’ practice bulletin on gestational diabetes states that there is no consensus regarding fetal surveillance for women with diet-controlled gestational diabetes. However, local practice may include non-stress and contraction stress testing, amniotic fluid determination, and biophysical profile; this may start as early as 32 weeks to or as late as 40 weeks, based upon the total cumulative risk to the fetus from all potential complications.2 The American Diabetes Association states that increased fetal surveillance is appropriate but is not any more specific with this recommendation.1