How long do you need to use backup contraception when starting Depo-Provera (medroxyprogesterone acetate)?

Backup Contraception Requirements When Starting Depo-Provera

When starting Depo-Provera (medroxyprogesterone acetate), you need to use backup contraception for 7 days unless the injection is given within the first 5 days of your menstrual cycle or within 2 weeks of your previous injection if you're late for a repeat dose. 1

Timing of First Depo-Provera Injection

The need for backup contraception depends on when you start Depo-Provera:

Starting During Menstrual Cycle

• First 7 days of menstrual cycle: No backup contraception needed 1
• After day 7 of menstrual cycle: Use backup contraception (condoms) for 7 days 1, 2

Starting After Pregnancy

• Postpartum (breastfeeding):

  • If <6 months postpartum, amenorrheic, and fully/nearly fully breastfeeding (≥85% of feeds): No backup contraception needed 1, 3
  • Otherwise: Use backup contraception for 7 days 1

• Postpartum (not breastfeeding):

  • Use backup contraception for 7 days unless started within 7 days of delivery 1

• Post-abortion:

  • If given within 7 days of abortion: No backup contraception needed 1
  • If given at the time of surgical abortion: No backup contraception needed 1
  • Otherwise: Use backup contraception for 7 days 1

For Repeat Injections

• Less than 2 weeks late (<15 weeks since previous injection): No backup contraception needed 1, 3
• 2 weeks or more late: Use backup contraception for 7 days 1, 3

Scientific Rationale

The 7-day backup contraception recommendation is based on research showing that Depo-Provera takes time to establish contraceptive effectiveness. Studies have shown that:

• When Depo-Provera is administered between days 10-13 of the menstrual cycle, 30% of women still ovulated 2
• Cervical mucus changes begin within 24 hours but take up to 3 days to become consistently hostile to sperm 4
• By day 7 after injection, cervical mucus scores reached zero (maximally hostile to sperm) in most women 4

Common Pitfalls to Avoid

1. Not using backup when needed: Many unintended pregnancies occur during the first week after starting Depo-Provera outside the first 5 days of the menstrual cycle 5

2. Assuming immediate effectiveness: Despite rapid changes in cervical mucus, complete contraceptive effect takes up to 7 days 4

3. Missing the follow-up injection: Set a reminder for your next injection before the 13-week mark to avoid needing backup contraception 3

4. Forgetting backup after late injection: If more than 2 weeks late for a repeat injection, treat as a new start and use backup for 7 days 1

The CDC and American Academy of Family Physicians guidelines consistently recommend 7 days of backup contraception when starting Depo-Provera outside the first week of the menstrual cycle to ensure adequate contraceptive protection 1, 3.