Study: Implantable Contraceptives Work
Analysis Shows the Birth Control Method Is Effective in Preventing Pregnancy
WebMD News Archive
July 18, 2007 -- Implantable contraceptives are highly effective for preventing pregnancy and seem to be well tolerated by the women who use them, a review of the research shows.
The combined analysis included nine studies comparing different implantable contraceptives. More than four out of five women who participated in the studies had the implants for two years or longer, suggesting that they were satisfied with the birth control method.
The most common side effect with the implants was irregular menstrual bleeding, with cessation of periods increasing with duration of use.
"Menstrual disturbances are common, and these side effects should be explained to women before the implant is inserted so that women can make an informed choice about their contraceptive strategy," says researcher Jo Power of London's Margaret Pyke contraceptive center.
Implantable Contraceptives in the U.S
Implantable contraception has had a rocky history in the U.S and was not even an option for women in this country for several years before 2006.
Exactly one year ago, the FDA approved Implanon, a matchstick-sized implant that delivers a steady dose of the hormone progestin to prevent pregnancy for up to three years.
Implanon is inserted by a doctor under the skin of the upper arm, and it can be removed at any time.
The single-rod delivery system for Implanon is designed to minimize the risk of the removal problems that plagued the first implantable contraceptive to become available in North America, Wyeth Pharmaceutical's Norplant.
Approved for sale in the U.S. in 1990, Wyeth stopped marketing the contraceptive here a decade later due to quality-control issues and a rash of lawsuits by women who said they were injured when having Norplant's six rods removed.
Wyeth also market's a two-rod implantable contraceptive outside the U.S. -- sold as Jadelle -- but has no plans to introduce it here, a company spokeswoman tells WebMD.
The newly published research review, conducted for the independent, health practices analysis group Cochrane Collaboration, found all three implantable contraceptives to be very effective for preventing pregnancy, but there were some differences between them.
Not surprisingly, the one-rod Implanon and two-rod Jadelle proved to be quicker to implant and remove from the body than the six-rod Norplant.
Menstrual bleeding irregularities were common with all three implants, but Implanon users were twice as likely as Norplant users to have complete cessation of periods after two years of use.