Progestagen-only oral contraceptives: comparison of the metabolic effects of levonorgestrel and norethisterone. Comparative study on intermittent versus continuous use of a contraceptive pill administered by vaginal route. Randomised clinical trial to determine optimum initiation time of norgestrel-progestin only contraception in Eldoret Teaching Hospital, Kenya. A andomized contraceptive trial comparing a daily progestogen with a combined oral contraceptive steroid.
A 6-month single-blind study compared the use of a progestagen-only oral contraceptive containing norethisterone 350 micrograms/day (NE 350) with one containing levonorgestrel 30 micrograms (LN 30), to assess the metabolic effects. At the end of 6 months, there were no significant differences between the two groups with respect to plasma cholesterol, lipoproteins including HDL subfractions, triglycerides or glucose concentration. Levels of fibrinogen, plasminogen, Factor VII, Factor X and antithrombin III were also similar. Women changing from a combined oral contraceptive to LN 30 showed a significant fall in Factor X. Mean blood pressure fell on LN 30 by 7/9 mmHg, but the 6-month reading did not differ significantly from that in women on NE 350. Acceptability, and the metabolic effects of the two preparations were similar in this study. Further larger studies are warranted. A multicenter, international, randomized, comparative trial was conducted to assess the acceptability, efficacy and safety of two different schedules of a contraceptive pill, containing 250 micrograms levonorgestrel and 50 micrograms ethinyl estradiol, administered by the vaginal route. One schedule of daily administration for 21 days with a seven-day interruption to allow withdrawal bleeding was compared to daily administration without interruption for bleeding. A total of 900 women were recruited in three countries, Brazil, Egypt and China; 7,090 women-months of vaginal pill use were recorded (3,364 using the pills intermittently and 3,726 continuously). Four undesired pregnancies occurred, one in Egypt and three in China, all four in women using the pills intermittently. There was a statistically significant difference (p = 0.486) in pregnancy rate between the two groups. There were no other significant differences in discontinuation rates despite marked differences in bleeding patterns, amenorrhea predominating in the continuous use group. Hemoglobin levels increased significantly in the two groups but hematocrit was significantly higher in the continuous use group. In a randomised controlled trial to determine the optimum time of initiation of Ovrette, a progestin only oral contraceptive among postpartum women, who fully or nearly fully breast-fed their infants in the first six months, no difference was found between group 1 (initiating at six weeks postpartum) and group 2 (initiating the pill at return of menses or 6 months postpartum). There were no pregnancies in either group during the 18 month follow-up. There were no significant differences in the continuation rates between the two group. nan
Evidence is insufficient to compare progestin-only pills to each other or to combined oral contraceptives.