Synopsis
Distinguish traditional, desogestrel and drospirenone pills, apply exact late and missed-use rules, and manage interactions, bleeding and safe initiation without oestrogen.
- Traditional levonorgestrel or norethisterone POP has a three-hour late window, desogestrel has a 12-hour window and drospirenone has a 24-hour window; missed use begins beyond 27, 36 and 48 hours since the previous pill respectively.
- Take the missed pill as soon as remembered and continue at the usual time, even if two are taken in one day; use backup for 48 hours with traditional or desogestrel POP and seven days with drospirenone POP.
- Assess EC after unprotected sex from the time the first pill was missed until efficacy is re-established. Recent progestogen can reduce UPA effect, so use the current EC algorithm.
Key red flags
A traditional POP is missed when more than 27 hours have elapsed since the last pill, desogestrel after more than 36 hours and drospirenone after more than 48 hours; the windows are not interchangeable.
After missed traditional or desogestrel POP, use condoms or abstain until 48 hours of correct use; after missed drospirenone POP, use additional precautions for seven days.
Enzyme inducers reduce every oral POP during use and for 28 days after stopping; DMPA, LNG-IUD and copper IUD effectiveness is unaffected.
New severe unilateral pain, collapse or bleeding with pregnancy possibility requires urgent ectopic-pregnancy assessment.
Drospirenone has antimineralocorticoid activity, so renal disease, adrenal insufficiency and interacting potassium-raising medicines require product-specific review.
More than 27 hours since the previous levonorgestrel or norethisterone pill is missed use and triggers 48-hour backup.
More than 36 hours since the previous desogestrel pill exceeds its 12-hour allowance and needs 48-hour backup.
More than 48 hours since the previous active drospirenone pill exceeds its 24-hour window and requires seven-day backup.
Pain, bleeding or collapse with a positive or possible pregnancy requires urgent pregnancy-location assessment despite low absolute risk.
Investigation priorities
Determine the active ingredient, pack design and elapsed time since the last active tablet.
Management branches
A POP user reports a pill later than the scheduled time.
- Confirm traditional, desogestrel or drospirenone formulation and calculate hours since the previous active tablet.
- Apply the 27-, 36- or 48-hour threshold, take an active pill now and continue the pack.