TABLE 4

Contraceptive methods rated ‘effective’

Type of contraception	How it works	Failure rate^a	Advantages	Disadvantages
Injectable contraceptives	A long-lasting progestin is injected into the muscle or under the skin every 12 weeks	< 1%–6%	Provides effective, prolonged contraception with no exposure to estrogen; return to fertility in 6–12 months	May cause weight gain and mood changes; can also cause amenorrhea
Patch	Estrogen and progestin are absorbed through the skin; applied once a week for 3 weeks; no patch during week 4	< 1%–9%	Easy to use; return to fertility in a few cycles; can be used continuously for ovulation suppression and menstrual regulation	Can cause localized skin rash; may detach
Vaginal ring	Estrogen and progestin are absorbed through the vagina; placed in vagina for 3 weeks of every month	< 1%–9%	Easy to use; fertility returns in a few months	Local symptoms, such as increased vaginal discharge
Combined oral contraceptives	Contain both estrogen and progestin taken once a day for 3 weeks of every month or 3 months (extended cycle)	< 1%–9%	Reduces menstrual cramps and menorrhagia; easy to use; return to fertility in a few months	Intermittent bleeding and spotting are the most common adverse effects; increased risk of thrombosis; should be taken at the same time every day
Extended-cycle combined oral contraceptives	Can be taken continuously for 3 weeks	< 1%–9%	Reduces menstrual cramps and menorrhagia	Intermittent bleeding and spotting are the most common adverse effects
Progestin-only pills	Contain progestin only, taken daily	< 1%–9%	Can be used by women who cannot use estrogen	Vaginal bleeding and spotting are common; fertility may take a few months to return after contraception discontinued; should be taken consistently every day at the same time every day

↵a Within first year; lower number is with ideal consistent use, whereas higher number is with typical use.
Based on information in references 21 and 23.