Orawan Kiriwat

A multicentred phase III comparative clinical trial of depot-medroxyprogesterone acetate given three-monthly at doses of 100mg or 150mg: 1. Contraceptive efficacy and side effects

Two dosages of depot-medroxyprogesterone acetate (DMPA), 100 mg and 150 mg given every 90 days, were compared in two groups of women with regard to effectiveness, reported complaints and reasons for discontinuation. A total of 1216 women were recruited into a seven-centre, multinational, randomized clinical trial. Follow-up was for a period of one year and resulted in a total of 5507 woman-months of experience of 100 mg DMPA and 5429 woman-months of experience of the 150 mg dose. The study showed little difference in efficacy and side effects between the two treatment groups. Two pregnancies occurred in women receiving 100 mg DMPA giving a Pearl Index of 0.44 per 100 woman-years. None occurred in the 150 mg group. There was no difference in the overall continuation rates between the two groups at one year, being 59.3% in the 100 mg group and 58.8% in the 150 mg group. Except for discontinuation of method use for amenorrhea, the rates of all medical and non-medical reasons given for discontinuation were comparable between the two treatment groups. Womens perception of lack of bleeding was reported as amenorrhea and resulted in discontinuation rates at 12 months for amenorrhea of 7.2% for women receiving 100 mg of DMPA and 12.5% for those receiving the 150 mg dose. Three centres, Alexandria, Karachi and Szeged, made the major contributions to this difference.

Clinical performance of a new two-rod levonorgestrel contraceptive implant : A three-year randomized study with Norplant® implants as controls

In a randomized three-year clinical trial at seven clinics, the performance of levonorgestrel rod (LNG ROD) implants used by 600 women was compared with that of soft tubing NORPLANT implants used by 598 women. No pregnancies occurred in either group of women and, accordingly, body weight did not affect the efficacy of either type of implant. There were neither statistically significant nor important differences in termination rates for any reason over the three years. Complaint and illness rates during use of either of the two implant types were statistically indistinguishable and were attributable to the same set of conditions. Seventy-one per 100 of the women using each implant regimen continued to the three-year point, for an average annual continuation rate of 89 per 100. Removals of LNG ROD implants were accomplished in about half the time required for removal of Norplant capsule implants (p < 0.001).

Levonorgestrel concentrations during 7 years of continuous use of Jadelle contraceptive implants.

Serum levonorgestrel concentrations were assayed in a multicenter, 7-year study of 199 users of Jadelle rod implants. We examined drug levels, patterns of changes, factors affecting drug levels, and concentrations at which pregnancies occurred. Mean levonorgestrel concentrations declined from 435 pg/mL at 1 month of use to 64% of that value (280 pg/mL) at the end of 3 years. Between the end of the third and fifth years neither mean nor median serum levels varied markedly. At 5 years the mean concentration was again 64% of the first months mean. Declining levels were observed thereafter through the end of 7 years when the mean, 224 pg/mL, was 52% of the 1-month value. Last measured drug concentrations of women who became pregnant during Jadelle use had mean and median values of 152 and 144 pg/mL, respectively, and a maximum value of 180 pg/mL. Analyses indicated ponderal index, body weight, duration of use, and a single clinical center were the most important variables affecting measured levonorgestrel levels. Approximately one-third of assays in the sixth and seventh years were found to be below 180 pg/mL, suggesting that Jadelle levonorgestrel implants would not maintain sufficiently high levels of effectiveness against pregnancy after 5 years and that heavier women would then be at greater risk of pregnancy.

Prolonged effectiveness of Norplant® capsule implants: a 7-year study

Soft tubing Norplant(R) contraceptive implants were studied in 1210 women for 7 years to measure the duration of effectiveness and the magnitude of the pregnancy rates over that time. Mean age at enrollment was 27.4 years. Of the enrollees, 42% were US residents. One-sixth (16.1%) weighed >/=70 kg at the time of implant placement. At the end of 5 years, the cumulative pregnancy rate was 1.1/100; at the end of 7 years, it was 1.9/100. No pregnancies occurred to any of the 400 women who enrolled in the study at age >/=30 years and who weighed <100 kg. Among women aged 18-33 years, the 7-year Norplant pregnancy rates are comparable to the median pregnancy rates of tubal sterilization methods for women of the same age and duration of use. For women aged >/=34 years, without regard to weight at admission, the 7-year effectiveness of soft tubing Norplant equals or surpasses that of tubal sterilization. For continuing implant users, annual pregnancy rates <1.0/100 in years 6 and 7, together with low cumulative pregnancy rates, testify that Norplant capsule implants remain highly effective for 7 years.

A multicentred phase III comparative study of two hormonal contraceptive preparations given once-a-month by intramuscular injection: II. The comparison of bleeding patterns

A multicentred Phase III clinical trial was conducted in 12 countries to compare HRP112 (depot-medroxyprogesterone acetate, 25 mg and estradiol cypionate, 5 mg) and HRP102 (norethisterone enantate, 50 mg and estradiol valerate, 5 mg) given every 28 days. Contraceptive efficacy and side-effects of both regimens were reported previously. Their effect on vaginal bleeding patterns is the object of this paper. A total of 2320 women were randomly assigned to each drug and 2000 of them provided a menstrual diary. The comparison of the bleeding patterns is made using a 90-day reference period approach and following the guidelines published by WHO. The analysis failed to identify any major difference in the vaginal bleeding patterns induced by both contraceptive preparations. For both drugs, the first bleeding episode following the first injection occurs early. For 70% of users, this is followed by a regular vaginal bleeding pattern similar to an untreated pattern. Others experience irregular bleeding and a few have either infrequent or frequent bleeding. The extremes of amenorrhea and prolonged bleeding are rare. There are no major trends in vaginal bleeding patterns with prolonged use of either preparation. Women with the worst vaginal bleeding patterns discontinue early in the clinical trial and the last three months of experience have the most influence in their decision to stop using the contraceptive method. The analysis suggests how the life-table analysis of discontinuation reasons underestimates the true incidence of vaginal bleeding irregularities in a clinical trial.

A randomized, double-blind study of six combined oral contraceptives

A randomized controlled clinical trial comparing six combined oral contraceptives with 50 micrograms or less of ethinyl estradiol was undertaken in 10 WHO Collaborating Centres for Clinical Research in Human Reproduction. A total of 2430 women entered the trial and were observed for 28,077 woman-cycles. All low-dose combined oral contraceptives demonstrated equivalent efficiency with one-year pregnancy rates of one to six percent. However, discontinuation rates for medical reasons differed significantly between the treatment groups, with the preparation containing 20 micrograms ethinyl estradiol and that containing 400 micrograms norethisterone acetate being associated with higher discontinuation rates due to bleeding disturbances. Even among the preparations which did not differ in discontinuation rates, the reasons for discontinuation did differ. Women receiving norethisterone preparations tended to discontinue because of bleeding disturbances while those receiving the levonorgestrel-containing preparations tended to discontinue because of complaints of nausea and vomiting.

A multicentred phase III comparative clinical trial of depot-medroxyprogesterone acetate given three-monthly at doses of 100mg or 150 mg: II. The comparison of bleeding patterns

Abstract A multicentered phase III clinical trial was conducted in seven countries to compare two dosages of depot-medroxy progesterone acetate (DHPA), 100mg and 150mg, given every 90 days. Contraceptive efficacy and side-effects of both regimens were reported previously. Their effect on vaginal bleeding patterns is the object of this paper. A total of 1216 women were randomly assigned to a dose group and 1156 of them provided a menstrual diary. The comparison of the bleeding patterns is made using a 90-day reference period approach and following the guidelines published by WHO. In addition, the longest bleeding/spotting episode and the longest bleeding/spotting-free interval are calculated over the entire diary lengtn. The only dirterence found between the two dose groups is a higher incidence of amenorrhea with the 150mg regimen. Overall, there is a high degree of consistency between the reasons given by individual women for discontinuing the contraceptive method and their vaginal bleeding pattern during the 90 days preceding discontinuations. However the data revealed large between-centre differences, both in the incidence of specific patterns, and in the identification by women of bleeding problems as reasons for discontinuation. This last point suggests that the life-table analysis underestimates the true incidence of menstrual irregularities. Comments on the reference period analysis method are made.

The monthly injectable contraceptive: a two-year clinical trial.

A contraceptive regimen of monthly intramuscular injections of a combination of 25 mg of medroxyprogesterone acetate and 5 mg of estradiol cypionate (Cyclo‐Provera, Upjohn Co, Kalamazoo, MI, USA) was studied in 111 Thai women through 2356 cycles. During the first two years of treatment, more than 80% of the patients had only one bleeding episode per cycle. The incidence of amenorrhea ranged from 3.6% to 14.9%. Average cycle length and duration of bleeding were similar to the pretreatment values. High continuation rates (79% at 12 months) indicated good patient acceptance of the method. There were no contraceptive failures or serious side effects. Return of fertility was relatively prompt. Among 21 patients who had discontinued treatment in order to plan pregnancy, 10 were pregnant within six months, and 3 others conceived during the succeeding three months. In five volunteers, serum medroxyprogesterone acetate levels were below 5 ng/ml (with one exception) after a single injection of Cyclo‐Provera given at intervals up to 56 days.

Pharmacokinetics of oral contraceptive steroids after morning or evening administration

An oral contraceptive containing ethynyloestradiol and norethisterone was administered to six women in the morning and in the evening using a cross-over design. Serum levels of ethynyloestradiol and norethisterone were measured at various times after administration. There was no significant difference in a number of pharmacokinetic parameters between the two times of administration, suggesting that morning or evening administration of the contraceptive are equally effective.

Comparison of culdoscopic and laparoscopic tubal sterilization

The growing number of women requesting interval sterilization (apart from term delivery or abortion procedures) necessitates the re-evaluation of traditional surgical procedures. A total of 800 women--the first 400 women undergoing culdoscopic and laparoscopic tubal sterilization procedures at Siriraj Hospital in Bangkok, Thailand--evaluate the appropriateness of the two sterilization procedures for use in interval sterilization programs. No serious operative complications occurred in either group. However, the rate of postoperative complications was considerably higher for the culdoscopic group than for the laparoscopic group. Hospitalization was required for only a small percentage of the patients and most had resumed their normal activities within two days of the operation. This study indicates that both procedures are effective and may be safely performed on an outpatient basis without general anesthetics and with minimal discomfort for the patients.