A randomized, single blind comparative trial of norethindrone enanthate and depo-medroxyprogesterone acetate in Bangladesh

Depot medroxyprogesterone versus norethisterone oenanthate for long-acting progestogenic contraception

BACKGROUND

There are two injectable progestogen-only contraceptives (IPCs) that have been available in many countries in the world since 1983. They are both still extensively used in many developing countries, forming a large proportion of the health system's expenditure on contraception. These are depot medroxyprogesterone acetate (DMPA) and norethisterone oenanthate (NET-EN). These are both highly effective contraceptives that receive wide acceptance amongst women in their fertile years. They differ in frequency of administration that has implications on patient uptake. They also differ in cost that may significantly affect budgeting in the health system. A systematic comparison will aid to ensure their rational use.

OBJECTIVES

To determine if there are differences between depot medroxyprogesterone acetate given at a dose of 150 mg IM every 3 months and norethisterone oenanthate given at a dose of 200mg IM every 2 months, in terms of contraceptive effectiveness, reversibility and discontinuation patterns, minor effects and major effects.

SEARCH STRATEGY

We searched the computerized databases MEDLINE using PubMed, Popline, Cochrane Controlled Trials Register, Biblioline, LILACS, EMBASE and PASCAL for randomised controlled trials of DMPA versus NET-EN for long-acting progestogenic contraception. Studies were included regardless of language, and all databases were reviewed from the time that injectable progestogens have been in use.

SELECTION CRITERIA

All randomised controlled comparisons of DMPA acetate given at a dose of 150 mg IM every 3 months versus NET-EN given at a dose of 200mg IM every 2 months, used for contraception, were included. Trials had to report on contraceptive efficiency and return to fertility, discontinuation risks and reasons for discontinuation, and clinical effects, both menstrual and non-menstrual.

DATA COLLECTION AND ANALYSIS

BD and CM evaluated the titles and abstracts obtained through applying the search strategy and applied the eligibility criteria. BD attempted to contact authors where clarification of the data was required, and contacted all main manufacturers of the contraceptives. After inclusion of the two studies, the data was abstracted and analysed with RevMan 4.2.

MAIN RESULTS

Two trials were included in this review. There was no significant difference between the two treatment groups for the frequency of discontinuation for either contraceptive, although the women on NET-EN were 4% more likely to discontinue for personal reasons than those on DPMA. Discontinuation because of accidental pregnancy did not differ between the groups. Although the duration of bleeding and spotting events was the same in each group, women on DPMA were 21% more likely to develop amenorrhoea. Mean changes in body weight at 12 and 24 months, and in systolic and diastolic blood pressure at 12 months did not differ significantly between the studies.

AUTHORS' CONCLUSIONS

While the choice between DPMA and NET-EN as injectable progestogen contraceptives may vary between both health providers and patients, data from randomized controlled trials indicate little difference between the effects of these methods, except that women on DMPA are more likely to develop amenorrhoea. There is inadequate data to detect differences in some non-menstrual major and minor clinical effects.

Vaginal bleeding patterns of women using different contraceptive methods (implants, injectables, IUDs, oral pills)--an Indian experience. An ICMR Task Force Study. Indian Council of Medical Research

Irregularity in vaginal bleeding patterns is the most common clinical side effect causing discontinuation of the method reported by the-users of the newer contraceptive methods, especially hormonal ones. An objective assessment of vaginal bleeding pattern is, therefore, critical in evaluation of a new contraceptive method for its acceptance and continued use. The menstrual diary records of women participating in clinical trials of several contraceptive methods undertaken by the Indian Council of Medical Research were analysed. It was observed that the long-acting progestogen-only hormonal contraceptives like levonorgestrel (LNG)-releasing subdermal implants Norplant or intrauterine devices (LNG-IUD) as well as injectable contraceptive NET-EN 200mg given 2 or 3 monthly produced disturbances in bleeding pattern in the majority of their users. Very heavy or prolonged bleeding, a potential health hazard was uncommon and a shift more towards infrequent bleeding was observed. In Norplant-II implants users, 75 to 80% of women had irregularities in bleeding pattern during the first year of use which improved with prolonged use. However, even at 4 years of use, about half of the users of Norplant-II implants continued to have irregular bleeding patterns. The bleeding disturbances occurred in 80% users of 200mg NET-EN injectable contraceptives also during first year of use, however unlike Norplant-II implants users, there was no improvement with prolonged use. Combined monthly injectable contraceptives containing 50mg NET-EN and 5mg estradiol valerate caused less bleeding problems with half of the users experiencing normal pattern during one year of its use. Combined low-dose oral pills, both triphasic and monophasic, produced much better cycle control as compared to any of the other hormonal contraceptive-treated groups; about 90% of combined oral pill users had normal bleeding patterns during one year of method use. The use of copper IUDs was associated with increased bleeding in 18 to 20% of women during the initial period of three months which improved with prolonged use. It was observed that the women having frequent or prolonged bleeding had discontinued the contraceptive method more often as compared to those having delayed bleeding episodes or oligomenorrhoea. However, discontinuation rates due to bleeding irregularities at one year were lower in Norplant-II implants users as compared to other long acting hormonal contraceptive methods such as injectables or IUDs in spite of similar or better bleeding patterns in women using these methods.(ABSTRACT TRUNCATED AT 400 WORDS)

Patterns of depo-provera use in a large family planning clinic in the United States

Depot medroxyprogesterone acetate (DMPA) was approved as an investigational new drug for contraceptive use in the United States between 1967 and 1978. Patterns of contraceptive choice and changing methods were determined among 36,298 women attending a family planning clinic between 1967 and 1976. This population was the largest concentration of US women who had DMPA available as a contraceptive option. By 1974, women in the age group 35–49 were as likely to choose DMPA as either oral contraception or an intrauterine device. Coincidentally, use of the most popular choice, oral contraception, declined in older women and IUD use dropped sharply in all age groups. On average, users of DMPA were more likely to continue their method than were users of IUDs or barrier methods. Among women in the 35–49 age group, DMPA users were the group least likely to change methods.

Comparative evaluation of contraceptive efficacy of norethisterone oenanthate (200 mg) injectable contraceptive given every two or three monthly. Indian Council of Medical Research Task Force on Hormonal Contraception

A total of 2388 subjects, 1181 for 60 +/- 5-day and 1207 for 90 +/- 5-day treatment regimen with norethisterone oenanthate (NET OEN) 200 mg injection, were observed for 24 months, constituting 28,513 woman-months. This clinical trial represents the largest clinical trial undertaken on NET OEN. The observations indicated that NET OEN given at 60 +/- 5-day intervals provides adequate contraceptive protection. However, as compared to the published studies elsewhere, higher method failures were seen during the first six months of NET OEN usage, when all women were receiving the drug at 60 +/- 5-day intervals. The reasons for this discrepant observation in the present study cannot be explained. The higher method failures reported with 90 +/- 5-day regimen were mainly during the third month following the injection, suggesting reduced contraceptive efficacy of the drug during this period. Thin build women (body weight less than or equal to 40 kg) were at higher risk of involuntary pregnancy. Disrupted menstrual pattern was the major reason for discontinuation ranging between 42-43 per 100 users at the end of 24 months. Amongst these, amenorrhoea was the commonest reason for discontinuation. No change in blood pressure was observed during contraceptive usage. The majority of NET OEN users did not show any change in body weight. The overall continuation rates with NET OEN were lower than those observed in similar conditions with Cu-T 200 mm2 IUCD.