Unintended Pregnancy Percentages by Contraceptive

Method Unintended pregnancies
within 1st year of use (%)
Continuing use
at 1 year (%)
Typical use Perfect use Continued use
No method1 85    85   
Spermicides2 28    18     42
Fertility awareness–based
24     47
Standard days method  5   
Two day method  4   
Ovulation method  3   
Symptothermal method  0.4 
Withdrawal 22     4     46
 Parous women 24    20     36
 Nulliparous women 12     9   
 Female 21     5     41
 Male 18     2     43
Diaphragm5 12     6     57
Combined pill and
progestin-only pill
 9     0.3   67
Patch  9     0.3   67
NuvaRing  9     0.3   67
Depo-Provera  6     0.2   56
Intrauterine devices      
 Paragard (CopperT)  0.8   0.6   78
 Mirena (LNG 52mg)  0.2   0.2   80
 Skyla (LNG 13.5mg)  0.4   787
 Liletta (LNG 52mg)  0.55 
Implant  0.05  0.05  84
Female sterilization  0.5   0.5  100
Male sterilization  0.15  0.1  100
Lactational amenorrhea method6

Key: LNG = levonorgestrel

Typical use: Initiate use of a method, not necessarily for the 1st time. Percentage of couples who experience an accidental pregnancy during the 1st year if they do not stop use for any other reason. Estimates of the probability of pregnancy during the 1st year of typical use for spermicides and the diaphragm are taken from the 1995 National Survey of Family Growth (NSFG) corrected for underreporting of abortion; estimates for fertility awareness-based methods, withdrawal, the male condom, the pill and Depo-Provera are taken from the 1995 and 2002 NSFG corrected for underreporting of abortion.

Perfect use: Initiate use of a method, not necessarily for the first time and who use it perfectly both consistently and correctly. Percentage of couples who experience an accidental pregnancy during the 1st yr if they do not stop use for any other reason.

Continued use: Attempting to avoid pregnancy. Percentage of couples who continue to use a method for 1yr.

1The percentage becoming pregnant in the second and third columns are based on data from populations where contraception is not used and from women who cease using contraception to become pregnant. Among such populations, approximately 89% become pregnant within 1yr. This estimate was lowered slightly to 85% to represent the percentage who would become pregnant within 1yr among women not relying on reversible methods of contraception if they abandoned contraception altogether.

2Foams, creams, gels, vaginal supp, and vaginal film

3The ovulation and two day methods are based on evaluation of cervical mucus. The standard days method avoids intercourse on cycle days 8−19. The symptothermal method is a double-check method based on evaluation of cervical mucus to determine the 1st fertile day and evaluation of cervical mucus and temperature to determine the last fertile day.

4Without spermicides

5With spermicidal crm or jelly

6Highly effective, temporary method of contraception. Must use alternative contraception as soon as menstruation resumes, breastfeeding frequency/duration reduced, bottle feeds are introduced, or the baby reaches age 6mos to maintain effective protection against pregnancy.

7Based on 1432 women from combined 1-yr and 3-yr clinical trials.


Curtis KM, Jatlaoui TC, Tepper NK, et al. U.S. Selected Practice Recommendations for Contraceptive Use, 2016. MMWR Recomm Rep 2016;65(No. RR-4):1-66. https://www.cdc.gov/mmwr/volumes/65/rr/rr6504a1.htm. Accessed March 9, 2018.

Association of Reproductive Health Professionals. Choosing a Birth Control Method. https://www.arhp.org/Publications-and-Resources/Quick-Reference-Guide-for-Clinicians/choosing/failure-rates-table. Accessed March 9, 2018.

(Created 4/2018)