Results of a pilot study of the time to azoospermia after vasectomy in Mexico City.

ABSTRACT

In a joint pilot study by Family Health International (FHI), AVSC International, and the Instituto Mexicano del Seguro Social (IMSS), information was gathered on the determinants of azoospermia following vasectomy on 38 healthy men who chose vasectomy for contraception. The time and number of ejaculations associated with loss of sperm motility and loss of sperm eosin vital staining were also evaluated. "Azoospermia" was defined on the basis of two consecutive azoospermic semen samples collected at least 3 days apart. The single decrement life table method was used to calculate weekly gross cumulative life table rates for the time to azoospermia, zero motility, and zero viability. The Kaplan-Meier method was used to calculate the product-limit estimates of the cumulative rates for the total number of ejaculations to azoospermia, 0% motility and 0% viability. The median time to azoospermia was 10 weeks and at the end of week 20, the life table rate (+/- standard error) was 93.0 (+/- 6.30) weeks/100 men. The median number of ejaculations to azoospermia was between 25 and 30, and the cumulative rate (+/- standard error) at 60 ejaculations reached 94.5 (+/- 5.16)/100 men.

ABSTRACT

PIP The time and number of ejaculations to azoospermia after vasectomy were investigated in a prospective pilot study of 38 vasectomy acceptors conducted by Family Health International and the Instituto Mexicano del Seguro Social. Two consecutive azoospermic semen samples collected at least 3 days apart were required for azoospermia to be declared. 25 men (65.8%) demonstrated azoospermia during the 24-week follow-up period; however, 9 (23.7%) discontinued prior to the study's end or before achieving azoospermia. The median time to azoospermia was 10 weeks. At the end of week 20, the single decrement life table rate was 93.0 +or- 6.30 weeks per 100 men. The median number of ejaculations to azoospermia was 25-30 and the cumulative rate of azoospermia at 60 ejaculations was 94.5 +or- 5.16 per 100 men. It took approximately 5 weeks longer for men with fewer than three ejaculations per week to reach azoospermia than their counterparts with a higher number of ejaculations. The median time to sperm motility was 3 weeks, while that to 0% viability was 9 weeks. There were two pregnancies, one of which involved a man who had been declared azoospermic. An expanded study based on this pilot study is underway.