Oral contraceptives and incidence of ovarian cysts – adapted from Obstetrics and Gynecology, January 1994 – Tips from Other Journals
One small case series report and a recent case control study suggest that women who take multiphasic oral contraceptives have an increased risk of developing functional ovarian cysts. Because several million women currently take these medications for prolonged periods, any adverse effects have significant health implications. Grimes and colleagues conducted a six-month randomized control study to determine the effect of multiphasic oral contraceptives on the development of ovarian cysts.
Forty women used nonsteroidal contraception and kept menstrual diaries for three months before the study. They were then assigned randomly to one of four treatment groups for six months, followed by one month of post-treatment observation. Ten of the women received a triphasic oral contraceptive containing norethindrone, 0.5 mg, and ethinyl estradiol, 35 [mu]g, on days 1 through 7,0.75 mg and 35 [mu]g on days 8 through 14, and 1.0 mg and 35 [mu]g on days 15 through 21, followed by seven days of inert pills.
Women in the first group were compared with two groups of 10 women each who took monophasic pills for 21 days, followed by seven days of inert pills. One group took a pill containing norethindrone, 1.0 mg, and ethinyl estradiol, 35 [mu]g, and the other group received a pill containing norethindrone, 0.5 mg, and ethinyl estradiol, 35 [mu]g. The final 10 women in the study used nonsteroidal contraception such as barrier or surgical methods. During the month before treatment and in the post-treatment observation month, all women had vaginal ultrasound examination of both ovaries on days 7,14, 21 and 28 of the menstrual cycle.
During the six cycles of treatment, follicular cysts greater than 30 mm in diameter developed in 15 patients. These cysts were transient and the largest measured 54 mm x 49 mm. The relative risk of developing a follicular cyst was similar for women taking multiphasic pills and for those taking lower dose monophasic pills, and the relative risk was lower for women in both of these groups than for women taking the higher dose monophasic preparation. Compared with women taking multiphasic pills, the relative risks of developing a cyst greater than 10 mm during a cycle were 0.6 for women taking the higher dose monophasic, 1.0 for women taking the lower dose monophasic, and 1.2 for women using nonsteroidal methods of contraception.
The authors conclude that lower dose monophasic oral contraceptives or multiphasic contraceptives do not offer the protection against the development of functional ovarian cysts that is conferred by high-dose monophasic oral contraceptives. (Obstetrics and Gynecology, January 1994, vol. 83, p. 29.)
COPYRIGHT 1994 American Academy of Family Physicians
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