International study shows Norplant safe, effective
Data continue to show that Norplant is a safe and effective method of birth control, as evidenced by findings shared at a recent implant workshop convened by the Institute of Medicine in Washington, DC.
Look to new post-marketing surveillance to confirm Norplant’s high contraceptive efficacy, says Olav Meirik, MD, PhD. These results will be published soon by the Special Programme of Research, Development, and Research Training in Human Reproduction (HRP), a joint effort of the World Health Organization in Geneva, Switzerland, the United Nations Development Programme in New York, the United Nations Population Fund in New York, and the World Bank in Washington, DC. Meirik serves as head of HRP’s research component on surveillance and evaluation.
8 countries participate
The study included women from eight countries (Bangladesh, Chile, China, Colombia, Egypt, Indonesia, Sri Lanka, and Thailand) who enrolled in 32 centers. From 1989 to 1991, 7,977 women choosing Norplant and 8,044 women choosing IUD or sterilization (6,625 IUD and 1,419 sterilization) were recruited for the study and followed for five years, irrespective of change of contraceptive method in course of the study. The overall loss to follow-up was 3.6%.
The study confirms the high contraceptive efficacy of Norplant and copper IUDs: an average of 0.25 pregnancies per 100 woman-year for Norplant and 0.87 per 100 woman-year for copper IUDs, Meirik says. This research was a joint effort by Family Health International of Research Triangle Park, NC, the Population Council of New York, and the HRP.
Similar results were shared by Irving Sivin, MA, senior scientist with the Population Council. In a comparison of current Norplant implants with new two-rod levonorgestrel implants, Population Council data show very few problems with the implant method.1,2 The new two-rod implants were dubbed the LNG Rod by the
Population Council, its developers. The LNG Rod differs from the original Norplant II formulation, which used a different elastomer product. (For more information on the two-rod system, see the June 1996 issue of Contraceptive Technology Update, p. 70.)
For purposes of the presentation, Sivin examined five-year data from the two recently pub
lished studies and one unpublished study, then looked at all hospitalizations that had occurred over the five years since the Population Council began its new set of studies on Norplant and the LNG Rod. In all his research, he found a single death.
"We had more than 9,000 years of experience," Sivin said. "With women in this age group, we would expect approximately six deaths. We experienced one death, and that looks pretty good."
Despite the good results that have been turning up in the latest medical journals, few women are choosing the implant method.
"The data are pretty consistent in showing that very low proportions of women in the United States are using implants," says Jacqueline E. Darroch, senior vice president and vice president for research at Alan Guttmacher Institute in New York. "Certainly, it is not the growth that people would have thought would have occurred."
Darroch based her research on usage numbers from the soon-to-be published 1995 National Survey of Family Growth and information on attitudes about methods from the 1996 Ortho Birth Control Study.3
"It can be a very safe and effective method, and some women who use it absolutely love it, but not many women are trying it," she says.
The two-rod levonorgestrel implant received approval from the U.S. Food and Drug Administration in Washington, DC, in 1996, says Population Council spokeswoman Sandra Waldman. It has yet to enter the U.S. commercial market.
Some delay may have occurred while Wyeth-Ayerst Laboratories of Philadelphia, marketers of the Norplant implant, handled a spate of lawsuits filed by women who claimed they were injured by its use. An important turn of events occurred in February of this year, when a federal judge in Texas ruled that five such product liability lawsuits should not receive a hearing.4
The ruling, issued Feb. 24 by U.S. District Court Judge Richard Schell, stated that physicians and patients had been adequately informed about the method’s risks. Neither Wyeth nor the plain-tiffs have been allowed to comment on the case.5 Even though the company still faces a number of lawsuits in state courts, this determination scored a major victory for the method.
The implant workshop was designed to bring a wide cross-section of researchers, physicians, policy analysts, and women’s groups to the table to examine a specific contraceptive as a case study and to propose ideas on how best to introduce a new contraceptive when it becomes available in the future, says Polly F. Harrison, PhD, senior program officer with the Institute of Medicine.
Look for complete results of the workshop to be available later this year when they are published by the Institute through the National Academy Press.
References
1. Sivin I, Lähteenmäki P, Ranta S, et al. Clinical performance of a new two-rod levonorgestrel contraceptive implant: a three-year randomized study with Norplant implants as controls. Contraception 1997; 55:73-80.
2. Sivin I, Lähteenmäki P, Ranta S, et al. Levonorgestrel concentrations during use of levonorgestrel rod (LNG ROD) implants. Contraception 1997; 55:81-85.
3. Ortho Pharmaceutical Co. 1996 Annual Ortho Birth Control Study. Raritan, NJ; 1996.
4. Norplant Contraceptive Products Liability v. American Home Products Corp. 955 F. Supp. 700 (E.D. TX, 1997).
5. Barnett AA. U.S. Norplant product-liability suits fail. Lancet 1997; 349:708.
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