Timing of starting a POP

Progestogen-only pills (POPs) can be started at any stage of the menstrual cycle (see Quick Start). If pregnancy cannot be excluded, a pregnancy test is recommended 4 weeks after starting, or 3 weeks after starting if no further episodes of unprotected sex occurred in the first week of use. For general advice about excluding pregnancy, see Starting intrauterine contraception.

The POP is immediately effective if:

• started on day 1 to 5 of a regular menstrual cycle
• started less than 21 days postpartum
• started within 5 days of an abortion
• switching from an etonogestrel implant or depot medroxyprogesterone injection
• switching from a copper IUD during day 1 to 5 of a regular menstrual cycle
• switching from a combined oral contraceptive (COC) or vaginal ring and the person has either taken active COC pills (or used the vaginal ring) for the previous 7 days
• switching from a different POP, provided the person has taken at least 3 days of a levonorgestrel- or norethisterone-containing POP, or 7 days of a drospirenone POP.

If switching from a COC or vaginal ring to any type of POP and the person has had less than 7 days of active COC pill or vaginal ring use, additional cover is advised for the first 7 days of POP use; options are to continue the COC or vaginal ring for 7 days or use barrier methods or abstinence.

POPs containing levonorgestrel or norethisterone take 48 hours (3 consecutive pills) to work at all other times, and if the current method of contraception is not effective at the time of switching (eg late doses, injection or replacement). Drospirenone POPs take 7 days to work at all other times.

For more information about time to effectiveness when switching between contraceptive methods, see printable table.