Obgyn · Year 3 · from Obgyn

Case 1: Newly Diagnosed Gestational Diabetes - Diet-Controlled

Patient Demographics

• Age: 30 years
• Sex: Female
• Occupation: Administrative assistant

Chief Complaint

"My doctor said my glucose test was abnormal."

History of Present Illness

The patient is G2P1 at 26 weeks gestation. She underwent routine one-hour glucose challenge test (50 g) at 24 weeks, which returned at 156 mg/dL (threshold 140 mg/dL at her institution). She then completed a three-hour glucose tolerance test (100 g) with the following results:

• Fasting: 98 mg/dL (threshold 95)
• 1-hour: 195 mg/dL (threshold 180)
• 2-hour: 168 mg/dL (threshold 155)
• 3-hour: 130 mg/dL (threshold 140)

She has no symptoms of diabetes. Her first pregnancy was uncomplicated with a 3,400-gram infant delivered vaginally.

Risk Factors for Gestational Diabetes

• BMI 32 kg/m2 (obesity)
• Family history of type 2 diabetes (mother)
• Hispanic ethnicity

Physical Examination Findings

• Vital Signs: BP 118/74 mmHg, HR 76 bpm
• BMI: 32 kg/m2
• General: Well-appearing, overweight
• Abdomen: Gravid, fundal height 26 cm, appropriate for dates

Diagnosis

Gestational Diabetes Mellitus (A1GDM initially, pending diet trial)

• Two abnormal values on 3-hour GTT (fasting and 1-hour)
• Meets Carpenter-Coustan criteria

Initial Management

Diabetes Education:

• Referred to certified diabetes educator
• Glucose monitoring instruction
• Dietary counseling with registered dietitian

Self-Monitoring of Blood Glucose (SMBG):

• Fasting glucose every morning (goal <95 mg/dL)
• 1-hour or 2-hour postprandial after each meal
• 1-hour goal: <140 mg/dL
• 2-hour goal: <120 mg/dL

Medical Nutrition Therapy:

• 2,000-2,200 kcal/day (moderate restriction for BMI 32)
• Carbohydrate counting: 175-200 g/day
• Distribute carbohydrates: 3 meals + 2-3 snacks
• Complex carbohydrates, high fiber
• Evening snack to prevent overnight ketosis

Physical Activity:

• 30 minutes moderate walking after meals (improves postprandial glucose)

Two-Week Follow-up

Glucose Log Review:

Assessment:

• All fasting values <95 mg/dL
• All postprandial values <140 mg/dL (1-hour)
• Excellent dietary compliance

Diagnosis Refined: Gestational Diabetes - Diet-Controlled (A1GDM)

Ongoing Management

Continued Monitoring:

• Weekly glucose logs reviewed
• Growth ultrasound at 32 weeks, then every 4 weeks

Fetal Surveillance:

• Diet-controlled GDM with good control: may not require antenatal testing
• Kick counts starting at 28 weeks
• NST at 40 weeks if not delivered

Delivery Planning:

• Diet-controlled GDM: can await spontaneous labor until 40+6 weeks
• No indication for cesarean based on GDM alone
• Induction at 41 weeks if not delivered

Postpartum Management

• Discontinue glucose monitoring after delivery
• 75-g OGTT at 4-12 weeks postpartum to screen for persistent diabetes
• Counsel on 50% lifetime risk of developing type 2 diabetes
• Encourage weight loss, exercise, and breastfeeding (reduces diabetes risk)

Clinical Image

Image Description: Self-monitoring blood glucose device with glucose log demonstrating the target values for fasting and postprandial glucose in gestational diabetes management.

Attribution: Educational illustration. Public domain.

All cases for this lecture as Markdown