Multinational comparative clinical evaluation of two long-acting injectable contraceptive steroids: Norethisterone oenanthate and medroxyprogesterone acetate: 1. Use-effectiveness

The use of safe and effective contraception is essential for preventing unplanned pregnancy in women of all body sizes. When counseling women with obesity about contraception, it is important to consider the pharmacokinetic alterations of obesity on various modern contraceptive methods. However, evidence is reassuring that most contraceptive methods are safe and effective in women with obesity. Individual countries and the World Health Organization have published Medical Eligibility Criteria to guide contraceptive selection in women with medical issues including obesity. When choosing contraception, specific risks of the method relative to any underlying medical disorders must also be balanced against the risks of unintended pregnancy in this group.

The rising rate of overweight and obesity is a public health crisis in the United States and increasingly around the globe. Rates of contraceptive use are similar among women of all weights, but because contraceptive development studies historically excluded women over 130% of ideal body weight, patients and providers have a gap in understanding of contraceptive efficacy for obese and overweight women. Because of a range of drug metabolism alterations in obesity, there is biologic plausibility for changes in hormonal contraception effectiveness in obese women. However, these pharmacokinetic changes are not linearly related to body mass index or weight, and it is unknown what degree of obesity begins to affect pharmacokinetic or pharmacodynamics processes. Overall, most studies of higher quality do not demonstrate a difference in oral contraceptive pill effectiveness in obese compared with non-obese women. However, data are scant for women in the highest categories of obesity, and differences by progestin type are incompletely understood. Effectiveness of most non-oral contraceptives does not seem to be compromised in obesity. Exceptions to this include the combined hormonal patch and oral levonorgestrel emergency contraception, which may have lower rates of effectiveness in obese women. The purpose of this review is to summarize evidence on contraceptive use in women with obesity, including differences in steroid hormone metabolism, contraceptive effectiveness, and safety, compared with women of normal weight or body mass index using the same methods.

Use of contraception lowers a woman's risk of experiencing an ectopic pregnancy. In the case of method failure, however, progestin-only contraceptives may be more likely to result in ectopic pregnancies than some other methods such as combined hormonal and barrier contraceptives.

To describe ectopic pregnancy risk associated with use of implants and progestin-only injectable contraceptives through a systematic review of published studies.

We searched electronic databases for articles in any language published through May 2015 describing studies of progestin-only injectables and implants. We also searched bibliographies and review articles for additional studies.

Studies that reported any pregnancies were included in the review. Independent data extraction was performed by two authors based on predefined data fields, and where possible, we calculated the proportion of pregnancies that were ectopic and the ectopic pregnancy incidence rate per 1000 woman–years.

Fifty-three studies of implants and 28 studies of injectables were identified; 79% reported pregnancy location. The proportion of ectopic pregnancy ranged from 0 to 100% with an incidence of 0–2.9 per 1000 woman–years in studies of marketed levonorgestrel implants. Studies of etonogestrel implants and the injectables, depot-medroxyprogesterone acetate and norethisterone enanthate, reported few ectopic pregnancies.

Progestin-only contraceptive implants and injectables protect against ectopic pregnancy by being highly effective in preventing pregnancy overall; however, the absolute risk of ectopic pregnancy varies by type of progestin. Risk of ectopic pregnancy should not be a deterrent for use or provision of these methods.

As the proportion of women with obesity increases worldwide, understanding the influence of body weight on sexual behavior, fertility, and contraceptive effectiveness is critical for health-care professionals and patients. Although many have theorized that obese women are different from normal-weight women regarding sexual health and behavior, current evidence for the most part disproves this. The exception is in adolescents where body image may play a role in riskier behavior, placing them at a greater risk of an unintended pregnancy. Given that most modern contraceptives were not originally evaluated in obese women, understanding how weight affects contraceptive pharmacokinetics and efficacy should be a focus of ongoing research. Evidence is reassuring that most modern contraceptive methods are safe and effective in obese women. This paper reviews what is known about sexual and contraceptive behavior, as well as the effectiveness and pharmacokinetics of modern contraceptives, for overweight and obese women.

This study was an open trial where 1994 subjects each received Depo Provera injectable contraceptive every three months for one year and were observed a total of 20,294.3 woman months. At the time of observation, only one accidental pregnancy had occurred giving a use-effectiveness rate of 99.94% and a cumulative continuation rate of 72.87%. There were no significant adverse effects on weight and blood pressure. The main side effects were spotting, prolonged bleeding, and amenorrhea and these were also the main reasons of discontinuation. Complaints related to bleeding problems gradually decreased and complaints of amenorrhea increased with continued use. In lactating women, side effects occurrence rate was lower and continuation rate was higher in comparison with non-lactating women. Users did not report any effect on milk secretion. The results of this study confirm that Depo Provera is a very effective contraceptive method. With appropriate counseling and medical support, high acceptability and continuation rate can be achieved. Depo Provera is especially suitable for lactating women and could become a popular contraceptive method for lactating Chinese women.