Low-Dose Pill with New Progestogen Is as Effective As Current Formulations
A new low-dose combination oral contraceptive is effective, safe and acceptable to women, according to a study of 326 women recruited from six centers in the United States.1 Women's pregnancy rates and levels of intermenstrual bleeding with the new pill are comparable to those of women who use other low-dose combination pills.
Yasmin, the new contraceptive, contains 3 mg of a new synthetic progestogen called drospirenone and 30 mcg of ethinyl estradiol. Drospirenone was developed to provide an alternative for women who sometimes experience adverse effects with current oral contraceptives--principally, thrombosis, hypertension, weight gain, breast pain and acne. Like progesterone (but unlike other synthetic progestogens), drospirenone promotes the excretion of sodium and water, and therefore may reduce water retention symptoms. In addition, because it is antiandrogenic, it may help prevent users from developing acne.
Researchers recruited 18-35-year-old women from six centers in the United States for their study of the new pill. Women were eligible to participate if they were within 25% of ideal body weight, at risk of becoming pregnant and willing to use an oral contraceptive for at least 13 menstrual cycles. Women were excluded from the research if they smoked more than 10 cigarettes a day; were older than 30 and smoked; had used injectable hormones within the previous three months or a contraceptive implant within the previous six months; or had diabetes, high blood pressure or other conditions that are contraindications for oral contraceptive use. The analyses are based on 326 women, the majority of whom were white. The mean age of the participants was 26; 54% had used the pill prior to participating in the study.
The women received packages containing 28 pills and were instructed in their use. They returned to the centers for office visits at the end of cycles one, three, six, nine and 13; three months after cycle 13; and one year after the completion of the study. Women responded to a questionnaire about menstrual symptoms (including impaired concentration, water retention, mood changes, increased appetite, feelings of well-being and undesirable hair change) upon enrolling in the study and at the end of cycle six. The questionnaire asked about symptoms during the four-day period prior to menstruation, throughout menstruation and during the remainder of the cycle.
Study participants were given complete physical and gynecologic examinations upon enrolling in the study and at the end of cycles six and 13. Women's body weight and blood pressure were measured at each visit to the center.
Sixty-seven percent of the sample completed all 13 cycles, and 73% missed no pills during the study period. Only one woman became pregnant, yielding a rate of effectiveness (0.5 pregnancies per 100 woman-years of use) similar to that associated with other low-dose pills.
More than half (54%) of the women reported no intermenstrual bleeding, and 30% reported intermenstrual bleeding during only one or two pill cycles. Intermenstrual bleeding was most common during the first pill cycle. Breakthrough bleeding with spotting occurred among 1-5% of all participants per cycle and among 19% of participants during at least one cycle. Breakthrough bleeding alone occurred among no more than 2% of all women per cycle and among 2% of women during at least one cycle. Thirty percent of women experienced spotting alone during at least once cycle; the proportion ranged from 5% to 20% per cycle. Five percent of women experienced amenorrhea at the end of the first cycle. After cycle one, amenorrhea occurred for 1-5% of women per cycle and for 21% of women in at least one cycle. These levels of breakthrough bleeding, spotting and amenorrhea are similar to those reported in studies of other low-dose oral contraceptives.
Women were significantly less likely to report mood changes and water retention in all three menstrual phases after cycle six than they were upon enrollment in the study. For the premenstrual and menstrual phases, women were significantly less likely to report an increased appetite after cycle six than they were at the beginning of the study. There were no significant changes during any menstrual phase in women's reports of impaired concentration, hair change or feelings of well-being.
Seventy-one percent of the women reported at least one adverse effect during the study. Five percent of the sample experienced headaches, and 9% said they experienced breast pain. Six percent discontinued use of the contraceptive, primarily because of uncontrollable mood, headache, nausea, dysmenorrhea, intermenstrual bleeding or depression; fewer than 2% cited each of these effects as their reason for discontinuing. No women reported experiencing serious side effects related to contraceptive use.
Weight loss was statistically significant at cycle six, and weight gain was significant at cycle 13. There was no significant change in the women's blood pressure or the results of their blood tests or urinalysis. In addition, women's cholesterol, triglyceride and lipoprotein levels remained normal.
The researchers conclude that the new pill, with its combination of drospirenone and ethinyl estradiol, is "effective, safe, and well tolerated" by women and that it "may decrease the severity of some menstrually related symptoms."--B. Brown
1. Parsey KS and Pong A, An open-label, multicenter study to evaluate Yasmin, a low-dose combination oral contraceptive containing drospirenone, a new progestogen, Contraception, 2000, 61(2):105-111.