The contraceptive implant comprises progestin-releasing rods that are inserted into a woman's upper arm. They are highly effective and are viable for 3–5 years depending on the type of implant used. They work primarily by thickening the cervical mucus and preventing ovulation. There are several implants available, with the original available six-rod (7-year) implant Norplant (Leiras Oy Pharmaceutical, Finland), currently in the process of being phased out and replaced with implants with one or two rods (Jadelle [Bayer Schering Pharma, Turku, Finland], Sino-Implant [II] [Shanghai Dahua Pharmaceutical Co. Ltd, China] and Implanon™ [Organon]), which are easier to insert and remove. Most data available on weight change associated with implants have been documented for Norplant as it has been available for longer; however, there is some information on the newer implants and these are reviewed here. Weight change is noted as a side effect of implants and has been recorded as a reason for discontinuation.
Norplant & Norplant-2 (Jadelle)
Norplant is a levonorgestrel-releasing subdermal contraceptive implant. This six-capsule implant is effective for up to 5 years. Although continuing to be a popular method in the developing world, it has been discontinued in the USA and the UK. Approved by the FDA in 1990, it was withdrawn from the market in 2002. The next-generation product with two rods, known as Norplant-2 or Jadelle, was approved by the FDA in 1996, but has yet to be marketed in the USA. The checkered history of the product in the USA included individual and class action lawsuits against Wyeth on the grounds that not enough warning had been given about side effects such as irregular menstrual bleeding and nausea. Reasons for discontinuation of both Norplant and Norplant-2 include weight gain.[68–72] In one of these studies, a 5-year follow-up of women in the USA and South America, women gained weight at an average of 1.1 kg per year. However, response to weight was variable, with 10% experiencing weight loss in the first year while 10% gained more than 7 kg. A study comparing adolescent Norplant and COC users in the USA found that Norplant users gained 4 kg compared with 2 kg in the COC group. There is limited information about which Norplant users may have been at higher risk of weight gain. One trial investigated if weight gain was more likely in obese adolescents but found no significant differences in weight gain over time between different baseline weight categories. When analyzed separately by population group, there was a trend for African–American adolescents who were heavier at baseline to increase in weight more than those in lower weight percentiles, and this was not observed in white adolescent users.
Implanon is an etonogestrel-containing single sterile rod implant. Implanon was introduced in 1998, and was the first and remains the only single-rod implant available. Since 1998, 2.5 million women have successfully used the implant in countries all over the world. In 2006, Implanon was approved by the FDA and is now available to women in the USA. It only needs to be replaced once every 3 years. To make sure it is used properly, it requires special training programs for healthcare professionals.
Weight gain has been reported in Implanon users, as well as given as a reason for discontinuation.[72–74] In one international multicentered study, the mean BMI of participants increased by 3.5% over 2 years, although 20% of women experienced an increase of over 10% in BMI. In the USA, mean weight gain in Implanon users was approximately 1 kg after 1 year and between 1–2 kg after 2 years. How much of the weight gain was related to Implanon is unknown as no nonhormonal controls were included. Several studies have found that just over 2% of women discontinue Implanon for reasons of weight gain.[72–74]
Expert Rev of Obstet Gynecol. 2011;6(1):45-56. © 2011
Expert Reviews Ltd.
Cite this: Weight Change and Hormonal Contraception: Fact and Fiction - Medscape - Jan 01, 2011.