When do contraceptive pills become effective, and is backup needed?
Protection depends on the pill type and when it is started relative to menstruation, childbirth or switching methods. Some require two days of backup, others seven days or product-specific instructions. One rule does not cover every pill or late dose.
Details
Combined pills
Many combined pills provide immediate protection when started during the first five days of a period, and usually require seven days of backup when started later. Some products have exceptions, so read the leaflet for your own pill rather than using instructions from another packet.
Not all mini-pills are identical
Traditional, desogestrel and drospirenone pills have different instructions. When started outside the immediate-protection window, some need two days of backup, while drospirenone generally needs seven. The permitted late-dose window also varies; it is not universally 12 hours.
If unprotected intercourse occurred
Contact a pharmacist or clinician promptly about emergency contraception and when to start the regular pill. Daily pills do not remove pregnancy risk from earlier intercourse. A pregnancy test at the appropriate time and backup contraception until protection is established may be needed.
Related reading: How do combined and progestogen-only contraceptive pills differ?.