What laboratory tests should be ordered at the 6‑week postpartum visit?

Postpartum Laboratory Testing at 6 Weeks

Women with a history of gestational diabetes should undergo a 75-g oral glucose tolerance test (OGTT) at 4-12 weeks postpartum using non-pregnant diagnostic criteria, while routine laboratory testing for uncomplicated pregnancies is not universally recommended. 1, 2, 3, 4

Risk-Stratified Approach to Postpartum Labs

For Women with Gestational Diabetes (GDM)

• Perform 75-g OGTT at 4-12 weeks postpartum (ideally 6-12 weeks) using standard non-pregnant diagnostic criteria 1, 2, 3, 4
• Do NOT use HbA1c for diagnosis at the postpartum visit due to antepartum treatment effects 1
• If normal, repeat screening at least every 3 years lifelong 2, 4
• Fasting glucose or self-monitored blood glucose should be checked 24-72 hours after delivery to rule out ongoing hyperglycemia 3

For Women with Hypertensive Disorders of Pregnancy

• Check blood pressure within 3-10 days of delivery for high-risk individuals 5
• If persistent proteinuria and/or hypertension at 3 months, refer to nephrology 6
• Screen for antiphospholipid antibodies after severe or early pre-eclampsia, IUGR, or intrauterine fetal death 6
• Do NOT routinely screen for inherited thrombophilia 6

For Women with Intrahepatic Cholestasis of Pregnancy

• Verify normalization of liver enzymes at 8-12 weeks postpartum 6

For Women with Thyroid Antibody Positivity (TPO-Ab+)

• Measure TSH at 6 months postpartum (or as clinically indicated) 7
• Women with type 1 diabetes, Graves' disease in remission, or chronic viral hepatitis should have TSH checked at 3 and 6 months postpartum 7

For Uncomplicated Pregnancies

• Routine hemoglobin screening is NOT recommended unless there are specific risk factors 6, 8, 9
• Blood testing should be reserved for women with:
  • Postpartum hemorrhage
  • Low third-day hemoglobin
  • New onset fatigue
  • Estimated blood loss >1500 mL 9
• Routine toxoplasmosis serology is NOT recommended 6

Common Pitfalls to Avoid

The evidence shows that many women receive unnecessary examinations (vaginal exams in 70% despite lack of indication) while missing targeted screening for high-risk conditions 8. The key is risk-stratification rather than universal testing.

Do not order routine CBCs in women with uncomplicated deliveries and no clinical symptoms—clinical assessment of blood loss through history and physical examination is typically sufficient 9. However, be vigilant about diabetes screening in the GDM population, as this represents a critical window for preventing future type 2 diabetes.

For women with bariatric surgery history, additional monitoring of nutritional parameters may be needed, but this extends beyond the standard 6-week visit 10.

The postpartum visit should focus on targeted screening based on pregnancy complications rather than blanket laboratory testing 6, 11.