Uterine flushing: a method to recover spermatozoa and leukocytes

The process of sperm transport from the cervix, where a leukocytic reaction is initiated, through the uterus to gain access to the site of fertilization is very poorly understood. This preliminary study was designed to utilize a uterine flushing technique to determine firstly, the number of spermatozoa that can be recovered from the uterine cavity at 4 h post-insemination, around the time of ovulation, and secondly, to establish whether the spermatozoa initiate a leukocytic response while present. Uterine flushing was carried out in 10 potentially fertile women at 4 h post-insemination with donor semen, 24-36 h after the onset of the luteinizing hormone (LH) surge. The flush fluid was analysed for the numbers of spermatozoa and leukocytes present. In 8/10 women spermatozoa were retrieved from the uterus, in consistently low numbers (median 46, range 3-415). In 5/5 women leukocytes were recovered (median, 2.75 x 10(8)/l, range 2.0 x 10(8)-12.7 x 10(8)/l) from an origin other than peripheral blood contamination. These results suggest firstly that the flushing technique was a consistent method for retrieving spermatozoa and leukocytes from the uterine cavity, secondly that only low numbers of spermatozoa can be retrieved on flushing and thirdly that the leukocytic reaction to spermatozoa extends to the uterine cavity.