The new low dose oral contraceptives

Triphasic oral contraceptives: review and comparison of various regimens

OBJECTIVE

To review and compare the risk-benefit profile of triphasic oral contraceptives with that of low-dose monophasic oral contraceptives.

DESIGN

Literature on currently marketed triphasics and monophasics.

PATIENT(S)

Healthy women of reproductive age.

MAIN OUTCOME MEASURE(S)

Comparison of the rationale for development, composition, mechanism, efficacy, menstrual cycle control, side effects, health benefits, and risk-benefit profile.

RESULT(S)

All triphasics contain ethinyl estradiol (0.025-0.040 mg/d) and one of several progestins in doses (0.05-1.0 mg/d) related to their relative potencies, which are substantially lower overall (total dose) than those in monophasics. The triphasics are highly efficacious. In general, menstrual cycle control and side effects are similar in both types, but triphasics containing the newer progestins (desogestrel, gestodene, and norgestimate) have better cycle control and a reduced incidence of androgenic side effects compared with those with norethindrone or levonorgestrel. Both triphasics and monophasics have minimal effects on carbohydrate and lipid metabolism and hemostasis parameters, and therefore comparable low risks of coronary heart disease. The health benefits of triphasics and monophasics are similar and include decreased incidence of unwanted and ectopic pregnancies, ovarian cysts, endometrial and ovarian cancers, benign breast disease, and acute pelvic inflammatory disease; less menstrual blood loss and iron deficiency anemia; and lower frequency of irregular bleeding and menorrhagia.

CONCLUSION(S)

The risk-benefit profiles of both triphasics and monophasics are favorable and similar.

Low-dose oral contraceptives: health consequences of discontinuation

Presently, the lowest effective estrogen dose available as a combination oral contraceptive (OC) in the United States is 20 microg of ethinyl estradiol (EE) with different progestins. Twenty micrograms of EE coupled with levonorgestrel results in fewer side effects and cycle control comparable with higher-dose pills. Differences between therapeutically equivalent and brand-name, low-dose oral contraceptives, with respect to the bioavailability of hormones, may interfere with contraceptive efficacy and increase breakthrough bleeding. One of the most common reasons why women discontinue OCs is increased breakthrough bleeding. Because after OC discontinuation most women switch to a less-effective method, or no method, of contraception, an increase in breakthrough bleeding could ultimately result in an increase in unintended pregnancy. Thus, substituting a therapeutically equivalent for a brand-name low-dose oral contraceptive may have significant clinical and economic effects on individual and public health.

Endometrial histology during use of a low-dose estrogen-desogestrel oral contraceptive with a reduced hormone-free interval

The object of the study was to determine the effect of a new low-dose ethinyl estradiol-desogestrel oral contraceptive on endometrial histology. The oral contraceptive regimen contained fixed doses of ethinyl estradiol (20 micrograms) and desogestrel (150 micrograms) for days 1-21, placebo on days 22 and 23, and ethinyl estradiol alone (10 micrograms) on days 24-28. Endometrial histology was assessed in tissue samples obtained during treatment cycles 13 and 14. All endometrial samples were sent to a central laboratory for processing and evaluation. No endometrial hyperplasia or metaplasia was found in the endometrial biopsy specimens obtained during cycles 13 and 14 in a subset of 12 women participating in a multicenter efficacy and safety study. These results suggest that this oral contraceptive regimen, which includes 5 days of unopposed ethinyl estradiol, is not associated with endometrial hyperplasia or metaplasia. The endometrial histologic findings observed in this study were similar to those observed during the use of 21-day combination oral contraceptive regimens.

Metabolic and endocrine effects of the desogestrel-containing oral contraceptive Mircette

OBJECTIVE

The purpose was to evaluate the metabolic effects of Mircette (brand of desogestrel/ethinyl estradiol and ethinyl estradiol), a low-estrogen, desogestrel-containing oral contraceptive.

STUDY DESIGN

Women taking Mircette were evaluated to determine its effects on lipid profiles (n = 74), carbohydrate metabolism (n = 25), and endocrine parameters (n = 53).

RESULTS

During cycles 3 and 6 of Mircette treatment, changes from baseline included mean increases in serum triglycerides and very low-density lipoprotein cholesterol ranging between 50% and 60%. Smaller mean increases were observed at these time points in high-density lipoprotein cholesterol subfraction 2 (range between 17% and 25%), total cholesterol (<10%), high-density lipoprotein cholesterol (range between 10% and 15%), and high-density lipoprotein cholesterol subfraction 3 (range between 9% and 13%), with only nominal changes (<6%) in low-density lipoprotein cholesterol and lipoprotein. Patients receiving Mircette showed no mean changes in fasting plasma glucose or serum insulin levels but did have modest increases in glucose and insulin levels after a glucose challenge. Mircette treatment suppressed follicle-stimulating hormone, luteinizing hormone, 17beta-estradiol, and progesterone to levels consistent with inhibition of ovulation and increased concentrations of thyroid- and cortisol-binding globulins.

CONCLUSIONS

Overall, Mircette treatment was associated with expected effects on the pituitary-ovarian axis, triglycerides, and serum binding proteins; a modest decline in glucose tolerance; and a favorable effect on lipid profiles as a result of increases in total high-density lipoprotein cholesterol and high-density lipoprotein cholesterol subfraction 2 in the absence of changes in total cholesterol or low-density lipoprotein cholesterol.

Ovarian activity in women taking an oral contraceptive containing 20 microg ethinyl estradiol and 150 microg desogestrel: effects of low estrogen doses during the hormone-free interval

OBJECTIVE

We assessed the effect of low ethinyl estradiol doses given during the nominally hormone-free interval of the Mircette (brand of desogestrel/ethinyl estradiol and ethinyl estradiol) contraceptive regimen on ovarian activity.

STUDY DESIGN

In a randomized, double-blind study, healthy women received 150 microg desogestrel and 20 microg ethinyl estradiol for 21 days followed by either placebo for 7 days (Mircette/placebo; N = 24) or placebo for 2 days and 10 microg ethinyl estradiol for 5 days (Mircette/ethinyl estradiol; N = 23).

RESULTS

During cycles 2 and 3, the Mircette/placebo group had a higher incidence of persistent ovarian follicles (eight subjects versus three subjects) and on average a greater maximum follicle diameter than the Mircette/ethinyl estradiol group. One Mircette/placebo subject probably ovulated in cycle 2, and another had a luteinized unruptured follicle; no such activity was seen in the in the Mircette/ethinyl estradiol group. The study medication was well tolerated, and there were no apparent between-group differences in vaginal bleeding patterns.

CONCLUSION

The Mircette regimen, which includes low ethinyl estradiol doses during the hormone-free interval, more effectively suppresses ovarian follicular activity with a low monthly estrogen dose.

An open-label, multicenter, noncomparative safety and efficacy study of Mircette, a low-dose estrogen-progestin oral contraceptive. The Mircette Study Group

OBJECTIVE

The primary efficacy and safety of Mircette (brand of desogestrel/ethinyl estradiol and ethinyl estradiol), an oral contraceptive containing 150 microg desogestrel and 20 microg ethinyl estradiol given for 21 days, followed by 2 days of placebo and then 5 days 10 microg ethinyl estradiol, was evaluated.

STUDY DESIGN

In a large, open-label, 18-month, multicenter trial, a total of 1143 of 1250 healthy female subjects contributed to the determination of extent of exposure, for an equivalent of 1080.8 woman-years of use.

RESULTS

Absence of withdrawal bleeding occurred in 5.5% of total cycles and intermenstrual bleeding occurred in 12.0% of total cycles. Breakthrough spotting was more common than breakthrough bleeding. The Pearl Index for total pregnancies during treatment was 1.02/100 woman-years. Fewer than 3% of subjects discontinued study participation, primarily because of menstrual problems, indicating that Mircette was an oral contraceptive acceptable to the women studied. Overall 73.6% of all subjects reported one or more adverse events, and a total of 43.9% of subjects reported drug-related adverse events. The most common drug-related adverse events reported included headache (8.5%), breast pain (7.3%), dysmenorrhea (4.2%), and menstrual disorder (4.2%). There were no reports of venous thromboembolic events or of significant changes in blood pressure, lipid metabolism, or serum glucose level.

CONCLUSION

The study confirmed that Mircette is a safe and efficacious oral contraceptive that is well tolerated and acceptable to women who have previously used oral contraceptives, as well as first-time users.

Inhibition of ovulation by an oral contraceptive containing 100 micrograms levonorgestrel in combination with 20 micrograms ethinylestradiol

Twenty-four healthy female volunteers with normal ovulatory cycles, aged between 20 and 34 years (27.5 +/- 4.3), were included in a single-center, non-comparative study to investigate the effect on inhibition of ovulation of an oral contraceptive containing 20 micrograms ethinylestradiol in combination with 100 micrograms levonorgestrel. At baseline, during three treatment cycles and post-treatment, ultrasonography was used to examine the ovaries, to measure follicular size, and to measure the thickness of the endometrium. Serum levels of LH, FSH, estradiol, progesterone, total testosterone, free testosterone, SHBG, and CBG were also measured. Compared with treatment cycle 1, an increase in residual ovarian activity (follicle grades 4-5) was observed in cycles 2 and 3. Mean levels of LH, FSH, 17 beta-estradiol and progesterone remained suppressed during treatment. No escape ovulation was observed during the treatment phase of the study and there were no pregnancies. Ovulation was noted to return rapidly in the posttreatment cycle. Subjective and objective tolerance of the present regimen was noted to be good. Results indicate that the monophasic oral contraceptive containing 100 micrograms levonorgestrel combined with 20 micrograms ethinylestradiol effectively inhibits ovulation, providing adequate suppression of ovarian activity.

Shorter pill-free interval in combined oral contraceptives decreases follicular development

The objective of the study was to determine the suppressive effect on ovarian activity of 20 micrograms ethinylestradiol plus 75 micrograms gestodene administered for 21 or 23 days. The study was designed as a double-blind, randomized, multicenter trial in 60 women. A pre-treatment cycle, three treatment cycles and a post-treatment period were monitored by ovarian ultrasound and by LH, FSH, 17 beta-estradiol and progesterone measurements every other day. No ovulation and no luteinized, unruptured follicle were observed. Suppression of ovarian activity was more pronounced by the 23-day regimen. 17 beta-Estradiol serum levels during the last six days of a cycle and during the first six days of the next cycle were significantly less (p < 0.05) in the 23-day regimen. The superiority of the 23-day regimen in comparison to the 21-day regimen with regard to the suppression of ovarian activity was shown in this study. The observed differences in the 17 beta-estradiol levels and follicular development between a 21-day and 23-day preparation combine to suggest that shortening the pill-free interval in combined oral contraceptives may increase the contraceptive safety margin in women on low-dose formulations.