INDICATIONS AND USAGE
1. Indications
Progestin-only oral contraceptives are indicated for the prevention of pregnancy.
2. Efficacy
If used perfectly, the first-year failure rate for progestin-only oral contraceptives is 0.5%. However, the typical failure rate is estimated to be closer to 5%, due to late or omitted pills. The following table lists the pregnancy rates for users of all major methods of contraception.
Table 2. Percentage of Women Experiencing an Unintended Pregnancy During the First Year of Typical Use and the First Year of Perfect Use of Contraception and the Percentage Continuing Use at the End of the First Year. United States.
%
of
Women
Experiencing
an
Unintended
Pregnancy
within
the
First
Year
of
Use
%
of
Women
Continuing
Use
at
One
Year3
1Among typical couples who initiate use of a method (not necessarily for the first time), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any reason.
2Among couples who initiate use of a method (not necessarily for the first time), and who use it perfectly (both consistently and correctly), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason.
3Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year.
4The percentage of women becoming pregnant noted in columns (2) and (3) are based on data from populations where contraception is not used and from women who cease using contraception in order to become pregnant. Among such populations, about 89% become pregnant within one year. This estimate was lowered slightly (to 85%) to represent the percentage that would become pregnant within one year among women now relying on reversible methods of contraception if they abandoned contraception altogether.
5Foams, creams, gels, vaginal suppositories, and vaginal film.
6Cervical mucus (ovulation) method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases.
7With spermicidal cream or jelly.
8Without spermicides.
9The treatment schedule is one dose within 72 hours after unprotected intercourse, and a second dose 12 hours after the first dose. The Food and Drug Administration has declared the following brands of oral contraceptives to be safe and effective for emergency contraception: Ovral (1 dose is 2 white pills), Alesse (1 dose is 5 pink pills), Nordette or Levlen (1 dose is 4 yellow pills).
1
0However, to maintain effective protection against pregnancy, another method of contraception must be used as soon as menstruation resumes, the frequency or duration of breastfeeds is reduced, bottle feeds are introduced, or the baby reaches 6 months of age.
Method
Typical
Use1
Perfect
Use2
(
1
)
(
2
)
(
3
)
(
4
)
Chance4
85
85
Spermicides5
26
6
40
Periodicabstinence
25
63
Calendar
9
OvulationMethod
3
Sympto-Thermal6
2
Post-Ovulation
1
Cap7
ParousWomen
40
26
42
NulliparousWomen
20
9
56
Sponge
ParousWomen
40
20
42
NulliparousWomen
20
9
56
Diaphragm7
20
6
56
Withdrawal
19
4
Condom8
Female(Reality)
21
5
56
Male
14
3
61
Pill
5
71
Progestinonly
0.5
Combined
0.1
IUDs
ProgesteroneT
2.0
1.5
81
CopperT380A
0.8
0.6
78
LNg20
0.1
0.1
81
Depo-Provera
0.3
0.3
70
LevonorgestrelImplants(Norplant)
0.05
0.05
88
FemaleSterilization
0.5
0.5
100
MaleSterilization
0.15
0.10
100
Emergency
Contraceptive
Pills
:Treatmentinitiatedwithin72hoursafterunprotectedintercoursereducestheriskofpregnancybyatleast75%.9
Lactational
Amenorrhea
Method
:LAMisahighlyeffective,temporarymethodofcontraception.1
0
Source:Trussell,J,ContraceptiveEfficacy.In:HatcherRA,TrussellJ,StewartF,CatesW,StewartGK,KowalD,GuestF,ContraceptiveTechnology:SeventeenthRevisedEdition.NewYork,NY:IrvingtonPublishers,1998.