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

Routine Antenatal Care at 20 Weeks Gestation

For a healthy pregnant woman at 20 weeks gestation with no medical complaints and no family history of GDM, the most appropriate action is to give iron supplements to prevent anemia (Option D). 1

Rationale for Iron Supplementation

Iron supplementation is the standard of care for all pregnant women during the second and third trimesters, regardless of risk factors:

• Iron demand increases dramatically during pregnancy, rising from 0.8 mg/day in early pregnancy to 7.5 mg/day in late pregnancy, and most women cannot meet this demand through diet alone 2

• Approximately 40% of women enter pregnancy with minimal or no iron stores (100-500 mg or less), which is insufficient for the 500 mg minimum required during pregnancy 2

• Without iron supplementation, 20% of pregnant women develop iron deficiency anemia by the third trimester 2

• Low-dose iron supplementation (20-65 mg/day starting at 20 weeks) effectively prevents iron deficiency anemia without significant gastrointestinal side effects 3, 4

• Iron supplementation benefits extend postpartum, with treated women maintaining better iron stores and their infants having higher serum ferritin levels 2

Why Other Options Are Not Appropriate at 20 Weeks

Option A: 24-Hour Urine Protein Test

• Not indicated for routine screening in asymptomatic women without hypertension or other risk factors 1
• This test is reserved for women with signs or symptoms of preeclampsia

Option B: Early Screening for Gestational Diabetes

• Standard GDM screening occurs at 24-28 weeks gestation for all pregnant women 1, 5
• Early screening (before 15 weeks) is only indicated for high-risk women with specific risk factors including: BMI ≥30 kg/m², previous GDM history, family history of diabetes in first-degree relatives, or high-risk ethnicity 6, 5
• This patient has no family history of GDM and no other mentioned risk factors, making her average-risk and appropriate for standard 24-28 week screening 1

Option C: Low-Dose Aspirin for Preeclampsia Prevention

• Aspirin prophylaxis is not universally recommended for all pregnant women 1
• This intervention is reserved for women with specific risk factors for preeclampsia (not discussed in the provided evidence for this clinical scenario)

Clinical Implementation

Iron supplementation should be initiated at 20 weeks gestation with:

• Dosage: 20-65 mg elemental iron daily 2, 3
• Lower doses (20 mg/day) are equally effective and better tolerated than higher doses 3
• Continue supplementation until delivery to maintain adequate maternal iron stores and prevent postpartum iron deficiency 2, 3

Common Pitfalls to Avoid

• Do not wait for anemia to develop before starting iron supplementation - prophylactic supplementation is more effective than treating established deficiency 2
• Do not assume dietary intake is sufficient - median dietary iron intake (9 mg/day) falls below the recommended 12-18 mg/day for fertile women 2
• Remember to schedule routine GDM screening at 24-28 weeks for this patient, as she still requires standard screening despite lacking high-risk features 1, 5