EFFECT OF DIFFERENT INSERTION REGIMENS ON SIDE-EFFECTS WITH A COMBINATION CONTRACEPTIVE VAGINAL RING

The study population included 159 women aged 18 to 37 years requiring contraception (60 in Sydney; 99 in Los Angeles). The design consisted of a 6-month study of a contraceptive vaginal ring (CVR) releasing 20 mu g ethinyl estradiol and 1 mg of norethindrone acetate daily over tw o successive cycles with a new ring on each of three different inserti on regimens. A total of 831 woman-months of exposure were recorded, an d 129 women completed the study. The overall incidence of side effects was similar in the two centers and differences between the insertion regimens were not observed. Transient nausea following insertion of a new ring (mainly lasting 0.5 to 48 h) was the most prominent side effe ct, with no significant difference between the insertion regimens (alt hough the incidence tended to be highest with bedtime insertion [34%] and lowest with early evening insertion and temporary removal during t he first night [27%]). Transient vomiting occurred in about 10% of wom en in the first 24 h after first insertion of a new ring. The incidenc e and severity of nausea was greatly reduced in cycle 2 with each regi men (6% to 9% of women). Nausea could be prevented by overnight soakin g of the ring in water before use. Other side effects such as headache , dizziness, uterine cramps, breakthrough bleeding, weight gain, and r ing expulsion occurred with similarly low frequency in all three inser tion groups. One pregnancy occurred with probable ovulation between cy cles 5 and 6, the only pregnancy recorded to date in studies with this ring. The study demonstrated that this effective and generally well t olerated CVR causes a relatively high incidence of transient nausea af ter insertion of a new ring, which is probably due to accumulation of ethinyl estradiol on the ring surface during storage. Acceptability is still high, and this particular CVR merits further development. (C) 1 997 Elsevier Science Inc. All rights reserved.