INDICATIONS AND USAGE
Levonorgestrel and ethinyl estradiol tablets are indicated for the prevention of pregnancy in women who elect to use oral contraceptives as a method of contraception.
Oral contraceptives are highly effective for pregnancy prevention. Table 2 lists the typical unintended pregnancy rates for users of combination oral contraceptives and other methods of contraception. The efficacy of these contraceptive methods, except sterilization, the IUD, and implants, depend upon the reliability with which they are used. Correct and consistent use of methods can result in lower failure rates.
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 withintheFirstYear of Use
% of Women
Continuing Use at OneYear3
Method (1)
Typical Use1(2)
Perfect Use2(3)
(4)
Chance4
85
85
Spermicides5
26
6
40
Periodic abstinence
25
63
Calendar
9
Ovulation Method
3
Sympto-Thermal6
2
Post-Ovulation
1
Cap7
Parous Women
40
26
42
Nulliparous Women
20
9
56
Sponge
Parous Women
40
20
42
Nulliparous Women
20
9
56
Diaphragm7
20
6
56
Withdrawal
19
4
Condom8
Female (RealityTM)
21
5
56
Male
14
3
61
Pill
5
71
Progestin only
0.5
Combined
0.1
IUD
Progesterone T
2
1.5
81
Copper T380A
0.8
0.6
78
LNg 20
0.1
0.1
81
Depo-Provera
0.3
0.3
70
LevonorgestrelImplants (Norplant)
0.05
0.05
88
Female Sterilization
0.5
0.5
100
Male Sterilization
0.15
0.10
100
Emergency Contraceptive Pills: The FDA has concluded that certain combined oral contraceptives containing ethinyl estradiol and norgestrel or levonorgestrel are safe and effective for use as postcoital emergency contraception. Treatment initiated within 72 hours after unprotected intercourse reduces the risk of pregnancy by at least 75%.9
Lactation Amenorrhea Method: LAM is a highly effective, temporary method of contraception.10
Source: Trussell J. Contraceptive efficacy. In: Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Kowel D, Guest F. Contraceptive Technology: Seventeenth Revised Edition. New York NY: Irvington Publishers; 1998.
1.Among 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.Among 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.Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year.
4.The 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.
5.Foams, creams, gels, vaginal suppositories, and vaginal film.
6.Cervical mucus (ovulation) method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases.
7.With spermicidal cream or jelly.
8.Without spermicides.
9.The treatment schedule is one dose within 72 hours after unprotected intercourse and a second dose 12 hours after the first dose. The FDA has declared the following dosage regimens of oral contraceptives to be safe and effective for emergency contraception: for tablets containing 0.05 mg of ethinyl estradiol and 0.5 mg of norgestrel 1 dose is 2 tablets; for tablets containing 0.02 mg of ethinyl estradiol and 0.1 mg of levonorgestrel 1 dose is 5 tablets; for tablets containing 0.03 mg of ethinyl estradiol and 0.15 mg of levonorgestrel 1 dose is 4 tablets.
10.However, 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.
Clinical Studies
The efficacy and safety of levonorgestrel and ethinyl estradiol were studied in 2 one-year clinical trials of subjects age 18 to 49. There were no exclusions for body mass index (BMI), weight, or bleeding history.
The primary efficacy and safety study (313-NA) was a one-year open-label clinical trial that treated 2,134 subjects in North America. Of these subjects 1,213 (56.8%) discontinued prematurely, including 102 (4.8%) discontinued by the Sponsor for early study closure.
The mean weight of subjects in this study was 70.38 kg. The efficacy of levonorgestrel and ethinyl estradiol was assessed by the number of pregnancies that occurred after the onset of treatment and within 14 days of the last dose. Among subjects 35 years or less, there were 23 pregnancies (4 of these occurred during the interval 1 to 14 days after the last day of pill use) during 12,572 28-day pill packs of use. The resulting total Pearl Index was 2.38 (95% CI: 1.51, 3.57) and the one-year life table pregnancy rate was 2.39 (95% CI: 1.57, 3.62). Pill pack cycles during which subjects used back-up contraception or were not sexually active were not included in these calculations. Among women 35 years or less who took the pills completely as directed, there were 15 pregnancies (method failures) resulting in a Pearl Index of 1.55 (95% CI: 0.87, 2.56) and the one-year life table pregnancy rate was 1.59 (95% CI: 0.95 to 2.67).
In a second supportive study conducted in Europe (315-EU), 641 subjects were randomized to levonorgestrel and ethinyl estradiol (n=323) or the cyclic comparator of 0.1 mg levonorgestrel and 0.02 mg ethinyl estradiol (n=318). The mean weight of subjects in this study was 63.86 kg. The efficacy analysis among women 35 years or less included 2,756 levonorgestrel and ethinyl estradiol pill packs and 2,886 cyclic comparator pill packs. There was one pregnancy in the levonorgestrel and ethinyl estradiol group that occurred within 14 days following the last dose. There were three pregnancies in the cyclic comparator group.
Inhibition of Menses (Bleeding Profile)
The bleeding profile for subjects in Study 313-NA also was assessed. Women with a history of unscheduled bleeding and/or spotting were not excluded from the study.
In those subjects who provided complete bleeding data, the percentage of patients who were amenorrheic in a given cycle and remained amenorrheic through cycle 13 (cumulative amenorrhea rate) was determined (Figure 2).
Figure 2: Percentage of Subjects with Cumulative Amenorrhea for Each Pill Pack through Pill Pack 13
When prescribing levonorgestrel and ethinyl estradiol, the convenience of having no scheduled menstrual bleeding should be weighed against the inconvenience of unscheduled bleeding and spotting (see
WARNINGS, 11
).
fig-2