I stopped depot medroxyprogesterone injection in October and had unprotected intercourse last night; can I start combined oral contraceptive pills now or should I wait?

Starting Birth Control Pills After Depo-Provera and Recent Unprotected Intercourse

You should consider emergency contraception immediately given last night's unprotected intercourse, then start birth control pills today without waiting, but you must use backup contraception (condoms) or abstain from sex for 7 consecutive days after starting the pills. 1

Emergency Contraception First

Since you had unprotected sex last night and are not currently protected by any contraceptive method (Depo-Provera wears off after 12-15 weeks, and you stopped in October), emergency contraception should be strongly considered 1:

• Copper IUD is the most effective emergency contraception option 1
• Ulipristal acetate or levonorgestrel are oral emergency contraception options 1
• If you choose ulipristal acetate, you must delay starting birth control pills for 5 days after taking it 1
• If you choose levonorgestrel or copper IUD, you can start pills immediately 1

Starting Birth Control Pills

Start the pills immediately today—do not wait for your next period 2, 1:

• Combined oral contraceptive pills can be started at any time if it is reasonably certain you are not pregnant 2
• The CDC explicitly states that waiting for the next menstrual period is unnecessary when switching from another method 2
• In situations where pregnancy status is uncertain, the benefits of starting pills likely exceed any risk, so start them now with a follow-up pregnancy test in 2-4 weeks 2

Critical 7-Day Backup Period

You must use condoms or abstain from sex for 7 consecutive days after starting the pills 2, 1:

• It takes approximately 7 consecutive days of pill-taking to suppress ovulation and restore full contraceptive effectiveness 1
• Since you are starting pills more than 5 days after any menstrual bleeding started (or have no regular cycles after Depo), the 7-day backup rule applies 2
• This is non-negotiable for pregnancy prevention 1

Ongoing Pill Management

Take pills at the same time every day to maintain consistent hormone levels 1:

• If one pill is late (<24 hours), take it immediately and continue—no backup needed 3
• If one pill is missed (24-48 hours late), take the most recent missed pill immediately and use backup contraception for 7 days 3
• If two or more pills are missed (≥48 hours late), take the most recent missed pill, discard others, and use backup contraception for 7 days 3

Follow-Up Considerations

• Have a pregnancy test if you don't have a withdrawal bleed within 3 weeks of starting pills 1
• Expect possible breakthrough bleeding or irregular cycles initially after the Depo-to-pill transition 1
• The pregnancy test in 2-4 weeks is important given last night's unprotected intercourse 2

Common Pitfall to Avoid

Do not assume you are protected immediately upon starting the pills—this is the most dangerous misconception. The 7-day window of vulnerability is absolute, and unprotected intercourse during this time can result in pregnancy 2, 1.