Table 1.

Contraceptive efficacy and discontinuation rates 6, 12.

Efficacy data	Typical use probability of failure	Discontinuation rate
LNG‐IUS 13.5 mg	0.0041	0.1400a
OC	0.0900	0.3300
Ring	0.0900	0.3300
Patch	0.0900	0.3300
Injection	0.0600	0.4400
Implant	0.0005	0.1400
IUD	0.0080	0.2200
IUS	0.0020	0.0700
Barrier methodsb	0.1800	0.5700
Withdrawal	0.2200	0.5400
No method (chance)	0.4600	0.0000
Calendar methods	0.2400	0.5300
Modern FAB methods	0.2400	0.5300

FAB, fertility awareness based; IUD, intrauterine device; IUS, intrauterine system; LNG‐IUS, levonorgestrel intrauterine system; OC, oral contraception.

^aAssumed equivalent to implant.

^bAssumed equivalent to condom.