What is the most appropriate action for a 20-week pregnant woman with no medical complaints and no family history of Gestational Diabetes Mellitus (GDM)?

Routine Iron Supplementation is Most Appropriate at 20 Weeks

For a 20-week pregnant woman with no medical complaints, no family history of GDM, and no high-risk features, routine iron supplementation (Option D) is the most appropriate intervention. 1

Why Iron Supplementation is Indicated

• The American College of Obstetricians and Gynecologists recommends iron supplementation for all pregnant women during the second and third trimesters, as iron demand increases dramatically during pregnancy and most women cannot meet this demand through diet alone. 1

• Iron deficiency anemia affects approximately 20% of pregnant women not taking supplementary iron, and prophylactic supplementation from 20 weeks of gestation prevents both iron deficiency anemia and iron deficiency without causing significant gastrointestinal side effects. 2, 3

• A daily supplement of 20-65 mg of iron from 20 weeks of gestation is adequate to prevent iron deficiency anemia and maintains better iron reserves both during pregnancy and postpartum. 2, 3

Why Other Options Are Not Appropriate

Option A: 24-Hour Urine Protein Test

• The American College of Obstetricians and Gynecologists does not recommend 24-hour urine protein testing for routine screening in asymptomatic women without hypertension or other risk factors. 1
• This test is reserved for women with signs of preeclampsia (hypertension, symptoms) or pre-existing renal disease, which this patient does not have.

Option B: Early GDM Screening

• This patient does not meet criteria for early GDM screening at 20 weeks. Standard screening occurs at 24-28 weeks of gestation for average-risk women. 4, 1

• Early screening (at 12-14 weeks or first prenatal visit) is only indicated for high-risk women with specific risk factors including: 5, 1

  • BMI ≥30 kg/m²
  • Previous history of GDM
  • Family history of diabetes in first-degree relatives
  • High-risk ethnicity (Hispanic, Native American, South/East Asian, African American, Pacific Islander)
  • Previous delivery of macrosomic infant (>4.5 kg)

• Since this patient has no family history of GDM and no other mentioned risk factors, she should follow standard screening at 24-28 weeks. 4

Option C: Low-Dose Aspirin for Preeclampsia Prevention

• Low-dose aspirin is indicated for preeclampsia prevention only in women with specific high-risk factors (history of preeclampsia, chronic hypertension, pregestational diabetes, renal disease, autoimmune disease, multifetal gestation, or multiple moderate risk factors). 4
• This patient has no mentioned risk factors warranting aspirin prophylaxis.

Clinical Implementation

The appropriate management at 20 weeks for this patient includes:

1. Initiate routine iron supplementation (20-65 mg elemental iron daily) to prevent iron deficiency anemia. 1, 2, 3

2. Plan standard GDM screening at 24-28 weeks of gestation using either the one-step (75g OGTT) or two-step approach (50g glucose challenge test followed by 100g OGTT if positive). 4, 1

3. Continue routine prenatal care with standard monitoring appropriate for gestational age.

Common Pitfalls to Avoid

• Do not delay iron supplementation until anemia develops, as prophylactic supplementation from 20 weeks is more effective than treating established deficiency. 2, 3

• Do not perform early GDM screening in average-risk women, as this increases costs without improving outcomes and may lead to unnecessary interventions. 5, 1

• Ensure the patient returns for standard GDM screening at 24-28 weeks, as this is the optimal window when insulin resistance peaks and GDM typically manifests. 4, 6