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. Table 1 lists the pregnancy rates for users of all major methods of contraception.
Table 1: 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.
Adapted from Hatcher et al, 1998, Ref. #1Emergency Contraceptive Pills: Treatment initiated within 72 hours after unprotected intercourse reduces the risk of pregnancy by at least 75%The 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 2 light-orange pills), Lo/Ovral (1 dose is 4 white pills), Triphasil
or Tri-Levlen (1 dose is 4 yellow pills)
Lactational Amenorrhea Method: LAM is highly effective, temporary method of contraceptionHowever, 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 six months of age.
Source: Trussell J, Contraceptive efficacy. In Hatcher RA, Trussel J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, Contraceptive Technology: Seventeenth Revised Edition. New York NY: Irvington Publishers, 1998.
% of Women Experiencing an Unintended Pregnancy within the First Year of Use
% of Women Continuing Use at One Year Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year
Method (1)
Typical UseAmong 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 other reason (2)
Perfect UseAmong 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 (3)
(4)
ChanceThe percents becoming pregnant 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 percent who would become pregnant within one year among women now relying on reversible methods of contraception if they abandoned contraception altogether
85
85
SpermicidesFoams, creams, gels, vaginal suppositories, and vaginal film
26
6
40
Periodic abstinence
25
63
Calendar
9
Ovulation Method
3
Sympto-Thermal Cervical mucus (ovulation) method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases
2
Post-Ovulation
1
CapWith spermicidal cream or jelly
Parous Women
40
26
42
Nulliparous Women
20
9
56
Sponge
Parous Women
40
20
42
Nulliparous Women
20
9
56
Diaphragm
20
6
56
Withdrawal
19
4
CondomWithout spermicides
Female (Reality)
21
5
56
Male
14
3
61
Pill
5
71
Progestin Only
0.5
Combined
0.1
IUD
Progesterone T
2.0
1.5
81
Copper T380A
0.8
0.6
78
LNg 20
0.1
0.1
81
Depo-Provera
0.3
0.3
70
Norplant and Norplant-2
0.05
0.05
88
Female Sterilization
0.5
0.5
100
Male Sterilization
0.15
0.10
100
Norethindrone tablets have not been studied for and are not indicated for use in emergency contraception.