Comparative study of the effects of two once-a-month injectable contraceptives (Cyclofem® and Mesigyna®) and one oral contraceptive (Ortho-Novum 1/35®) on coagulation and fibrinolysis

Injectable contraception: updates and innovation

PURPOSE OF REVIEW

Injectable contraception is a highly effective form of birth control that is globally popular. Recent research has focused on ways to make injectables such as depot medroxyprogesterone acetate (DMPA) more accessible and to improve the side-effect profile of injectables. This review will focus on new directions and approaches to the use of injectable contraception.

RECENT FINDINGS

Research in the area of injectable contraception has focused on improving access for women through home or self-injection, and also task-shifting and community-based distribution in low-resource areas. Specific to DMPA, studies have focused on lowering the overall dose of medication while maintaining efficacy, and improving drug-delivery systems. More research into the association between DMPA and HIV is needed, and also the effects of administration of DMPA at the time of medication abortion.

SUMMARY

Injectable contraceptives are an important part of the global method mix of highly effective birth control. Improving the accessibility and side effect profile of commodities such as DMPA will make injectables even more valuable for women seeking effective contraception.

The special programme of research in human reproduction: forty years of activities to achieve reproductive health for all

The Special Programme of Research in Human Reproduction (HRP), co-sponsored by the UNDP, UNFPA, WHO, and the World Bank, is celebrating 40 years of activities with an expansion of its mandate and new co-sponsors. When it began, in 1972, the main focus was on evaluating the acceptability, effectiveness, and safety of existing fertility-regulating methods, as well as developing new, improved modalities for family planning. In 1994, HRP not only made major contributions to the Plan of Action of the International Conference on Population and Development (ICPD); it also broadened its scope of work to include other aspects of health dealing with sexuality and reproduction, adding a specific perspective on gender issues and human rights. In 2002, HRP's mandate was once again broadened to include sexually transmitted infections and HIV/AIDS and in 2003 it was further expanded to research activities on preventing violence against women and its many dire health consequences. Today, the work of the Programme includes research on: the sexual and reproductive health of adolescents, women, and men; maternal and perinatal health; reproductive tract and sexually transmitted infections (including HIV/AIDS); family planning; infertility; unsafe abortion; sexual health; screening for cancer of the cervix in developing countries, and gender and reproductive rights. Additional activities by the Programme have included: fostering international cooperation in the field of human reproduction; the elaboration of WHO's first Global Reproductive Health Strategy; work leading to the inclusion of ICPD's goal 'reproductive health for all by 2015' into the Millennium Development Goal framework; the promotion of critical interagency statements on the public health, legal, and human rights implications of female genital mutilation and gender-biased sex selection. Finally, HRP has been involved in the creation of guidelines and tools, such as the 'Medical eligibility criteria for contraceptive use', the 'Global handbook for family planning providers', the 'Definition of core competencies in primary health care', and designing tools for operationalizing a human rights approach to sexual and reproductive health programmes.

Combination injectable contraceptives for contraception

BACKGROUND

Combination injectable contraceptives provide a highly effective, reversible method of preventing pregnancy, and they do not require daily administration or use at the time of coitus. Although they are used in many countries, their acceptability could be limited by method characteristics, such as the need to obtain a monthly injection or bleeding pattern changes.

OBJECTIVES

To assess the contraceptive efficacy, bleeding patterns, discontinuation, user preferences, and side effects of combination injectable contraceptives.

SEARCH STRATEGY

We searched computerized databases for randomized controlled trials of combination injectable contraceptives.

SELECTION CRITERIA

Randomized controlled trials were eligible if they compared a combination injectable with any other contraceptive method (e.g., a second combination injectable contraceptive, progestin-only injectable contraceptive, other hormonal contraceptive or barrier method) or placebo. We limited the review to currently marketed combination injectable contraceptives.

DATA COLLECTION AND ANALYSIS

One author evaluated all titles and abstracts from the literature searches to determine their eligibility. Two authors independently extracted data from the eligible trials. Data on contraceptive efficacy, bleeding patterns, continuation, and side effects were entered and analyzed with RevMan.

MAIN RESULTS

Combination injectable contraceptives include depot medroxyprogesterone acetate (DMPA) 25 mg plus estradiol cypionate (E(2)C) 5 mg, as well as norethisterone enanthate (NET-EN) 50 mg plus estradiol valerate (E(2)V) 5 mg. These contraceptives resulted in lower rates of early study discontinuation due to amenorrhea or other bleeding problems than progestin-only contraceptives. However, rates were higher for overall discontinuation and discontinuation due to other medical reasons. Acceptability results favored the combination injectable in one study and the progestin-only in another.Studies comparing two combination injectable contraceptives found that NET-EN 50 mg plus E(2)V 5 mg resulted in less overall discontinuation and less discontinuation due to amenorrhea or prolonged bleeding than DMPA 25 mg plus E(2)C 5 mg. However, these differences were not detected in all trials. The NET-EN plus E(2)V group also had more regular bleeding and fewer prolonged bleeding reference periods than the DMPA plus E(2)C group. The groups did not differ in their amenorrhea rates.

AUTHORS' CONCLUSIONS

While discontinuation rates can be viewed as a measure of method acceptability, the findings should be interpreted with caution since discontinuation depends on many factors. Future research should be directed toward interventions to improve the acceptability of combination injectable contraceptives, such as providing injections in settings more convenient than clinics, methods for women to administer their own injections, and counseling about possible bleeding pattern changes.

Effect of depomedroxyprogesterone acetate on coagulation parameter: a pilot study

OBJECTIVE

Recent studies have shown changes in coagulation factors, suggesting an increased risk of thrombotic events, in women on progestin-containing contraceptives. To investigate this, we studied the effects of injectable depomedroxyprogesterone acetate (DMPA), given as a contraceptive, on coagulation and inflammation markers.

DESIGN

Prospective nonrandomized study.

SETTING

Department of Obstetrics and Gynecology, University of Vermont College of Medicine.

PATIENT(S)

In this substudy of subjects undergoing a phase III trial comparing IM and SC DMPA, 14 healthy reproductive-age women were randomly assigned to receive either IM or SC DMPA every 3 months during a pharmaceutical trial.

INTERVENTION(S)

All subjects had blood samples obtained at baseline and 6 and 12 months.

MAIN OUTCOME MEASURE(S)

D-Dimer, C-reactive protein (CRP), antithrombin (AT), factor VIIIc, activated partial thromboplastin time (aPTT), and aPTT plus activated protein C (APC) were analyzed on all samples.

RESULT(S)

D-Dimer concentration was significantly decreased at 6 and 12 months with injectable DMPA compared t degrees o baseline. There was also a modest decrease in aPTT. The CRP, AT, factor VIIIc, and aPTT + APC were not significantly altered by the use of DMPA.

CONCLUSION(S)

In this preliminary study the decline in D-dimer represents a potentially beneficial change in coagulation function following the use of DMPA given SC or IM. A slight decrease in aPTT may reflect a prothrombotic tendency with this contraceptive, but in contrast with previous studies examining the effect of oral contraceptive this injectable progestin contraceptive did not demonstrate the adverse effect on markers for thrombosis risk.

Combination injectable contraceptives for contraception

BACKGROUND

Combination injectable contraceptives provide a highly effective, reversible method of preventing pregnancy, and they do not require daily administration or use at the time of coitus. Although they are used in many countries, their acceptability could be limited by method characteristics, such as the need to obtain a monthly injection or bleeding pattern changes.

OBJECTIVES

To assess the contraceptive efficacy, bleeding patterns, discontinuation, user preferences, and side effects of combination injectable contraceptives.

SEARCH STRATEGY

We searched computerized databases for randomized controlled trials of combination injectable contraceptives.

SELECTION CRITERIA

Randomized controlled trials reported in any language were eligible if they compared a combination injectable with any other contraceptive method (e.g., a second combination injectable contraceptive, progestin-only injectable contraceptive, other hormonal contraceptive or barrier method) or placebo. We limited the review to currently marketed combination injectable contraceptives.

DATA COLLECTION AND ANALYSIS

The primary reviewer evaluated all titles and abstracts from the literature searches to determine their eligibility. Two reviewers independently extracted data from the eligible trials. Data on contraceptive efficacy, bleeding patterns, continuation, and side effects were entered and analyzed with RevMan 4.2.

MAIN RESULTS

Combination injectable contraceptives include depot medroxyprogesterone acetate (DMPA) 25 mg plus estradiol cypionate (E(2)C) 5 mg, as well as norethisterone enanthate (NET-EN) 50 mg plus estradiol valerate (E(2)V) 5 mg. These combination injectable contraceptives resulted in lower rates of early study discontinuation due to amenorrhea or other bleeding problems, but had higher rates of discontinuation due to other reasons than the progestin-only comparison contraceptives. Studies comparing two combination injectable contraceptives found that NET-EN 50 mg plus E(2)V 5 mg resulted in less overall early discontinuation and less discontinuation due to amenorrhea or prolonged bleeding than DMPA 25 mg plus E(2)C 5 mg. However, these differences were not detected in all trials making this comparison. The NET-EN plus E(2)V group also had more cyclical (regular) bleeding and fewer prolonged bleeding reference periods than the DMPA plus E(2)C group. The groups did not differ in their amenorrhea rates.

AUTHORS' CONCLUSIONS

While discontinuation rates can be viewed as a measure of method acceptability, the findings should be interpreted with caution since discontinuation rates are dependent on many other factors. Future research should be directed toward interventions to improve the acceptability of combination injectable contraceptives, such as providing injections in settings more convenient than clinical sites, methods for women to administer their own injections, and counseling about possible bleeding pattern changes.