What is the recommended prenatal care plan for a pregnant woman diagnosed with gestational diabetes, including nutrition, glucose monitoring, medication, fetal surveillance, delivery timing, and postpartum follow‑up?

Prenatal Care in Gestational Diabetes

Initial Management: Medical Nutrition Therapy First

All women with gestational diabetes should begin with medical nutrition therapy (MNT), self-monitoring of blood glucose, and physical activity before initiating pharmacologic therapy. 1, 2

• Start MNT immediately at diagnosis with referral to a registered dietitian nutritionist for an individualized carbohydrate-controlled meal plan 1, 2
• Prescribe a minimum daily intake of 175g carbohydrate distributed across three small-to-moderate meals and 2-4 snacks 1, 2
• Carbohydrate is generally less well tolerated at breakfast than other meals; adjust distribution accordingly 1
• An evening snack may be necessary to prevent accelerated ketosis overnight 1
• Avoid hypocaloric diets that cause ketonemia; however, moderate caloric restriction (30% reduction) in obese women may improve glycemic control without ketonemia 1
• Encourage at least 150 minutes per week of moderate-intensity aerobic physical activity distributed over at least 3 days if not contraindicated 1, 3

Glucose Monitoring and Targets

Implement fasting and postprandial self-monitoring of blood glucose at diagnosis to achieve strict glycemic targets. 1, 2

Target glucose levels:

• Fasting plasma glucose: <95 mg/dL (5.3 mmol/L) 1, 2

• 1-hour postprandial: <140 mg/dL (7.8 mmol/L) 1, 2

• 2-hour postprandial: <120 mg/dL (6.7 mmol/L) 1

• Monitor fasting and postprandial glucose levels daily using self-monitoring of blood glucose 1, 2

• Continuous glucose monitoring (CGM) can be used as an adjunct to self-monitoring and may help achieve A1C targets 1, 2

• Target A1C <6% (42 mmol/mol) if achievable without significant hypoglycemia, but may be relaxed to <7% (53 mmol/mol) if necessary to prevent hypoglycemia 1, 2

Pharmacologic Therapy When MNT Fails

Initiate insulin therapy as first-line pharmacologic treatment if glucose targets are not achieved with MNT and physical activity within 1-2 weeks. 1, 2

• Insulin is the preferred medication for GDM when pharmacotherapy is needed 1, 2
• All types of insulin can be safely used during pregnancy and breastfeeding 1
• Glyburide (glibenclamide) has minimal placental transfer (4%) and is a useful adjunct when additional therapy is needed, though it may be less successful in obese patients or those with marked hyperglycemia 1
• Do not use metformin except in clinical trials, as it crosses the placenta and lacks sufficient safety data for routine use 1
• Carefully balance glyburide action with meals and snacks to prevent maternal hypoglycemia 1

Fetal Surveillance

Implement fetal surveillance based on glycemic control severity and presence of other risk factors. 1

• Perform fetal ultrasound screening for congenital anomalies if presenting with A1C ≥7.0% or fasting plasma glucose ≥120 mg/dL (6.7 mmol/l), as these levels are associated with increased risk of major congenital malformations 1
• Teach women to monitor fetal movements during the last 8-10 weeks of pregnancy and report immediately any reduction in perceived fetal movements 1
• Intensify fetal surveillance when pregnancy continues beyond 40 weeks' gestation 1
• Data are insufficient to determine whether surveillance beyond self-monitoring of fetal movements is indicated in women with diet-controlled GDM who meet glycemic targets and have appropriate fetal growth 1

Maternal Surveillance

Monitor blood pressure and urinary protein at each prenatal visit to detect preeclampsia, which occurs at increased rates in GDM. 1

• Measure blood pressure and urinary protein at every prenatal visit 1
• When corticosteroids for fetal lung maturity are indicated, do not withhold them because of GDM diagnosis, but intensify glucose monitoring and temporarily increase insulin doses as necessary 1
• Monitor for spontaneous preterm birth, which may be increased in untreated GDM 1

Delivery Timing and Planning

Deliver women with well-controlled GDM at 38-40 weeks' gestation in the absence of maternal or fetal compromise. 1, 4

• There are no data supporting delivery before 38 weeks' gestation in the absence of objective evidence of maternal or fetal compromise 1
• Delivery at 38 weeks reduces fetal macrosomia risk without increasing cesarean rates 4
• Delivery past 38 weeks can lead to increased rates of large-for-gestational-age infants without reducing cesarean delivery rates 1
• Intensify fetal surveillance if pregnancy continues beyond 40 weeks' gestation 1

Intrapartum glucose management:

• Monitor blood glucose during labor in women treated with insulin or glyburide to guide correction of maternal hyperglycemia and prevent fetal hypoxia and neonatal hypoglycemia 1
• Target blood glucose range of 110-160 mg/dL during labor and delivery 4

Postpartum Management

Test all women with GDM for persistent diabetes or prediabetes at 4-12 weeks postpartum using a 75-g oral glucose tolerance test (OGTT) with nonpregnancy diagnostic criteria. 1, 2, 5

Immediate postpartum (1-3 days):

• Measure fasting or random plasma glucose before hospital discharge to detect persistent overt diabetes 1
• Elevated values (fasting ≥126 mg/dL or random ≥200 mg/dL) should be confirmed with laboratory measurements 1
• Continue MNT and pharmacologic therapy if needed to maintain glycemic control during lactation 1

Early postpartum (4-12 weeks):

• Perform 75-g 2-hour OGTT using nonpregnancy diagnostic criteria, NOT A1C, as A1C may be artificially lowered by pregnancy-related red blood cell turnover and delivery blood loss 1, 5
• OGTT is more sensitive than A1C for detecting both prediabetes and diabetes in the postpartum period 1, 5
• Diabetes is diagnosed when fasting plasma glucose ≥126 mg/dL or 2-hour plasma glucose ≥200 mg/dL 1, 5
• If both values are abnormal on a single test, diabetes is confirmed; if only one value is abnormal, repeat testing is required 1

Long-term follow-up:

• Implement lifelong screening every 1-3 years using 75-g OGTT, fasting plasma glucose, or A1C, as women with GDM have a 50-60% lifetime risk of developing type 2 diabetes 1, 5
• Women with prediabetes should receive intensive lifestyle interventions and/or metformin to prevent progression to type 2 diabetes 1, 5
• Breastfeeding is recommended to reduce the risk of maternal type 2 diabetes and should be supported 1

Contraception and Future Pregnancy Planning

Discuss and implement effective contraception immediately postpartum, with consideration of long-acting reversible contraception. 1, 5

• All women with diabetes of reproductive potential should have a contraceptive plan discussed and implemented 1
• Women with a history of GDM should seek preconception screening for diabetes before subsequent pregnancies to identify and treat hyperglycemia and prevent congenital malformations 1, 5
• Effective contraception should be used until glycemic targets are achieved if planning future pregnancy 1

Common Pitfalls to Avoid

• Do not test for persistent diabetes immediately postpartum while hospitalized, as this has reduced sensitivity for detecting glucose intolerance 1, 5
• Do not use A1C for the 4-12 week postpartum screening, as it will miss cases due to pregnancy-related physiological changes 1, 5
• Do not delay postpartum OGTT beyond 12 weeks, as many women are lost to follow-up and miss critical diabetes screening 1, 5
• Do not assume normal glucose tolerance postpartum without testing, as a significant number of women will have persistent diabetes or prediabetes 1