Ectopic pregnancy without therapy despite previous failure with in vitro fertilization and a male partner with an extremely low hypoosmotic swelling test score: case report.

Abstract

To record an ectopic pregnancy achieved through natural intercourse despite previous implantation failure following in vitro fertilization-embryo transfer (IVF-ET) with a male partner who had an extremely low hypoosmotic swelling test (HOST) score.
A hypoosmotic swelling test was performed for the first time on the semen of a male partner who was advised previously that his sperm specimen was perfectly normal.
The standard semen parameters except normal morphology with strict criteria were normal. The HOST score was 33%.
The HOST score of 33% was the lowest level recorded in anyone achieving a pregnancy. The fact that it resulted in an ectopic pregnancy in a woman with apparently normal tubes and failure to achieve an intrauterine pregnancy despite transfer of 13 embryos with good morphology may suggest that the low HOST score inhibits the blastocyst from implanting in the uterus rather than from failure to develop a blastocyst from a multi-cell embryo.