Starting Birth Control After Menstrual Period: Timing and Considerations
Birth control can be started at any time during the menstrual cycle, not just after a period ends, using either a "first day start" or "quick start" approach as recommended by current CDC guidelines. 1
Optimal Timing for Starting Birth Control
The traditional belief that birth control must be started immediately after a period is outdated. Current guidelines provide more flexible options:
First Day Start
- Begin taking the first active pill on the first day of menstrual bleeding
- Provides immediate contraceptive protection with no need for backup method 1, 2
- Recommended by the FDA for many combined hormonal contraceptives 2
Sunday Start
- Begin taking the first active pill on the first Sunday after menstruation begins
- Requires 7 days of backup contraception 2
- Convenient for some women as it aligns pill-free intervals with weekends
Quick Start
- Begin taking the first pill immediately, regardless of cycle day
- Requires 7 days of backup contraception if not started during the first 5 days of the cycle 1
- Shown to improve short-term continuation rates compared to waiting for next menses 3
Why First Day/Early Cycle Starts Were Traditionally Recommended
Ensuring Non-Pregnancy: Starting during or immediately after menstruation provided reasonable certainty that the woman wasn't already pregnant 4
Immediate Protection: When started within the first 5 days of the menstrual cycle, hormonal contraceptives immediately suppress follicular activity, potentially providing immediate protection 5
Reduced Breakthrough Bleeding: Starting at the beginning of the cycle may reduce initial breakthrough bleeding in some women
Current Best Practices
The CDC and other authorities now recommend a more flexible approach:
- Contraception can be initiated at any time during the menstrual cycle if it is reasonably certain the woman is not pregnant 4, 1
- A 7-day period of backup contraception is needed if starting after the 5th day of the cycle 1
- Delaying contraception initiation may decrease adherence and increase pregnancy risk 6
Special Considerations
Postpartum Women
- Non-breastfeeding: Combined hormonal methods can be started 3 weeks postpartum due to thromboembolism risk 7
- Breastfeeding: Progestin-only methods can be started immediately; combined hormonal methods should be delayed until at least 6 weeks postpartum 1, 7
Post-abortion
Common Pitfalls to Avoid
Unnecessary Delays: Waiting for the next menstrual period to start contraception increases the risk of unintended pregnancy
Missing the First Pills: The risk of ovulation is greatest when the pill-free interval exceeds 7 days 5
Inconsistent Use: Typical use failure rates for oral contraceptives (7%) are much higher than perfect use rates (0.3%) due to missed pills 1
Bottom Line
The "quick start" approach (starting immediately) is now recognized as an effective strategy that may improve contraceptive adherence. While starting after a period was traditionally recommended, current evidence supports starting hormonal contraception at any time during the menstrual cycle with appropriate backup contraception for the first 7 days if needed.