Pregnancy Testing After Depo-Provera: Interpreting Results and Next Steps

Depo-Provera (DMPA) and Fertility

• Median return to ovulation: 9–10 months after last injection (range 3–18+ months).
• Pregnancy possible before first post-DMPA period.

Test Interpretation

• Urine hCG: Detects ~20–25 mIU/mL; positive ~1 day after missed period (if cycles resumed) or ~14 days post-conception.
• Serum quantitative β-hCG: Detects 1–2 mIU/mL; positive ~8–11 days post-conception. Serial doubling (48 h) confirms viability.
• False negatives: Testing too early, dilute urine, hook effect (very high hCG).
• False positives: Rare; hCG-secreting tumors, recent pregnancy loss, certain medications.

Recommended Approach

1. If amenorrheic on DMPA and pregnancy suspected → serum β-hCG (most sensitive).
2. If positive → transvaginal ultrasound at ~5–6 weeks (discriminatory zone 1500–2000 mIU/mL).
3. If negative but symptoms persist → repeat serum β-hCG in 48 h.

Counseling Points

• DMPA does not cause infertility; fertility returns.
• No teratogenic risk if conception occurs during DMPA use.
• Start prenatal vitamin with folate immediately if pregnancy confirmed.