Nepal: Pregnancies and Vasectomies -- May 7, 2003

Research Triangle Park, NC -- A study of 1,052 Nepalese men who had been sterilized with a form of vasectomy widely used in developing countries shows that the pregnancy rate after vasectomy is higher than previously thought.

"This study is unique in that it is the first time that we have attempted to evaluate the effectiveness of vasectomy in a large sample of men from diverse areas in Nepal," says Dr. Kalyan Raj Pandey, a member of the research team as well as president of the Nepal Medical Association and advisor to the Nepal Ministry of Health at the time of the study.

The research, undertaken by Family Health International (FHI) in collaboration with the Ministry of Health in Nepal, estimated a three-year pregnancy rate of 42 per 1,000 vasectomies, mostly performed using the ligation (tying) and excision (removal) technique. The study, published in the May 2003 issue of the journal Contraception, also estimated that during the first year after vasectomy, 17 women per 1,000 vasectomies would become pregnant.

"This contrasts with an estimated pregnancy rate of 1 to 2 per 1,000 vasectomies in the United States, where different vasectomy techniques are typical and where couples are much older," reports Hanif Nazerali, FHI's principal investigator for the study.

Coinvestigator Dr. Laxmi Raj Pathak, currently director general of health services at the Ministry of Health, says, "The findings have important implications for counseling, follow-up, and clinical training."

Dr. David Sokal, a medical director at FHI and another member of the research team, further emphasized that, "As we found with female sterilization, vasectomy is not 100 percent effective, although many patients tend to assume it is," he says. "While vasectomy is an excellent method of family planning, it is important that couples understand that a small but real possibility of pregnancy exists after the procedure."

Compared with other forms of family planning, the vasectomy procedure used in this study is still quite reliable. For instance, approximately 8 per 1,000 users of the Copper T intrauterine device will experience an unintended pregnancy during the first year of use. And for couples using condoms, approximately 30 to 140 women among every 1,000 will become pregnant during the first year.

Vasectomy is a permanent form of contraception in which the vasa deferentia -- the tubes that carry sperm from the testicles to the penis -- are blocked. Ligation and excision of a small length of the vas is the most common vasectomy technique in many developing countries, including Nepal. In high-resource settings, the use of cautery (burning) or metal clips, often with fascial interposition, is more frequent. (Fascial interposition is a technique in which the sheath covering the vas is pulled over one cut end of the tube and is then sewn shut to create a natural tissue barrier between the two cut ends.)

In the study from Nepal, researchers contacted men who had a vasectomy one to four years ago and asked each for a single semen sample for laboratory analysis. The men were also asked whether their wives had become pregnant. They were randomly chosen from more than 30,000 men who had vasectomies between 1996 and 1999.

Twenty-three men, or 2.3 percent, still had sperm in their semen after vasectomy, and 32 men reported that their wives had become pregnant during the years since the vasectomy. Pregnancies were more common among the younger women in the study. Eight of the pregnancies occurred within three months of the vasectomy, before a vasectomy is considered to be effective.

Recanalization (a spontaneous reconnection of the two ends of the vas that can occur following a vasectomy, often within a month or two) is the likely cause of most vasectomy failures, including those reported in Nepal. Additional research from FHI has shown that the risk of vasectomy failure is related to the surgical technique used for the procedure. More specifically, one study shows that fascial interposition can reduce the risk of vasectomy failure by about 50 percent when performed with ligation and excision. Some experts also recommend using cautery instead of ligation and excision to minimize failure rates.

In Nepal and other developing countries, where semen testing is generally not available, men are advised to wait 12 weeks before relying on a vasectomy to prevent pregnancy. Until that time, couples are advised to use other contraceptive methods, such as condoms.

This study included two special features: rigorous quality control of semen testing and Internet-based data entry. Semen samples obtained in Nepal were preserved and analyzed in Kathmandu, and then results were validated by a U.S. laboratory. To facilitate data collection and analysis, this study used an Internet link for data entry, from Kathmandu to FHI's office in North Carolina.

"We found the application of the technology easy and extremely efficient to process data and ensure its quality," says coinvestigator Dr. Shyam Thapa of FHI. Use of the technology reduced the time needed to process and verify data. This is the first study that FHI has conducted using the Internet in this way.

For more information from FHI on recent advances in vasectomy techniques, see Network, Vol. 21, #3. To read additional materials on the Internet-based data management system used in this study, see http://www.pharmalinkfhi.com/.

Source

Nazerali H, Thapa S, Hays M, Pathak LR, Pandy KR, Sokal DC. Vasectomy effectiveness in Nepal: a retrospective study. Contraception 2003;67(6):397-401.

FHI is dedicated to improving lives, knowledge, and understanding worldwide through a highly diversified program of research, education, and services in family health and HIV/AIDS prevention and care. Since our inception in 1971, FHI has formed partnerships with national governments and local communities in throughout the developing world to support lasting improvements in the health of individuals and the effectiveness of entire health care systems.