For a female patient with Polycystic Ovary Syndrome (PCOS) starting cyproterone acetate and ethinylestradiol (Combined Oral Contraceptive (COC)) tablets for contraception on a day other than days 1-5 of menstrual bleeding, does the medication provide protection against pregnancy after taking 9 pills?

Contraceptive Protection After 9 Pills of Combined Oral Contraceptive Started on Non-Menstrual Days

No, 9 pills do not provide adequate contraceptive protection when a combined oral contraceptive (COC) is started on a day other than days 1-5 of menstrual bleeding—you need 7 consecutive days of pills plus backup contraception during those 7 days to achieve protection. 1, 2, 3

Understanding the 7-Day Rule for COCs

When cyproterone acetate/ethinylestradiol (or any COC) is started more than 5 days after menstrual bleeding begins:

• Backup contraception is required for the first 7 consecutive days of pill-taking 4, 1, 2
• Protection begins after completing 7 consecutive days of active pills 1, 3
• This means contraceptive protection starts on day 8, not day 9 2, 3

Why 9 Pills Alone Are Insufficient

The mechanism of COC contraception requires time to suppress ovulation effectively:

• COCs prevent pregnancy primarily by suppressing ovulation 3
• The FDA labeling for ethinylestradiol-containing COCs explicitly states that 7 days of backup contraception are needed when starting after day 5 of the menstrual cycle 3
• The Centers for Disease Control and Prevention confirms this 7-day requirement across all COC formulations 4, 1, 2

Critical Timing Considerations

If the patient started pills on a non-menstrual day (outside days 1-5 of bleeding):

• She needed to use backup contraception (condoms) or abstain from sex during the first 7 days of pill-taking 1, 2, 3
• Any unprotected intercourse during those first 7 days carries pregnancy risk 2
• After completing 7 consecutive days of active pills correctly, protection begins 1, 3

Common Pitfall to Avoid

Do not confuse COCs with progestin-only pills (POPs), which only require 2 days of backup contraception 4, 1, 5. Cyproterone acetate/ethinylestradiol is a combined oral contraceptive containing both estrogen and progestin, therefore requiring the full 7-day backup period 1, 2, 3.

Practical Recommendation

For this first-time user who started on a non-menstrual day:

• If she has taken 9 pills consecutively and used backup contraception during the first 7 days, she is now protected 1, 3
• If she did not use backup contraception during the first 7 days and had unprotected intercourse, emergency contraception should be considered 1, 2
• A follow-up pregnancy test in 2-4 weeks may be warranted if there's any concern about unprotected exposure during the first week 1, 2