The "unexplained" poor postcoital test.
In 30 or 32 infertile couples with an unexplained negative or bad in vivo and in vitro sperm penetration test, we obtained a strongly positive Sperm Cervical Mucus Contact test (SCMC-test) and demonstrated the presence of antisperm antibodies in the male or female partner. In these 30 couples 25 of the male partners had a sperm-agglutination titre of at least 32 in the serum and at least 4 in the seminal plasma. In the five remaining couples the female partner showed a minimum sperm-agglutination titre of 16 in the serum and a cervical mucus titre of at least 128. In 48 couples with a fair or good sperm penetration in cervical mucus, in vivo and in vitro, we never found a strongly positive SCMC-test. In 43 of these couples the SCMC-test was negative. Only one man in the latter group had sperm-agglutinating activity in the semen. In a group 32 couples, with a negative SCMC-test, there was no or only weak sperm-agglutinating activity in the cervical mucus, although 2 women had moderate sperm-agglutinating activity in the blood serum. Based on these data we conclude that the so called "unexplained" poor postcoital test is almost always due to the presence of antisperm antibodies in the semen or in the cervical mucus. We consider the SCMC-test not only to be a simple and reliable technique for detecting the presence of these antisperm antibodies, but also a method of demonstrating the mechanism by which antisperm antibodies decrease the chance of conception.