A study of to determine if limiting the contact of sperm with zona pellucida reduces the rate of spontaneous abortions.

A recent study suggested that oligoasthenozoospermia may be an etiologic factor for spontaneous abortion (SAB) after in vitro fertilization-embryo transfer (IVF-ET). However, IVF-ET with intracytoplasmic sperm injection (ICSI) did not seem to be associated with an increased SAB rate. The study presented herein compared the rate of SAB in pregnancies achieved by IVF-ET according to the type of oocyte insemination process. The 3 types evaluated were conventional insemination, which exposed the oocyte to 25,000 sperm with prolonged contact (16-24 h), intermediate contact with a short insemination protocol where contact with 25,000 sperm was limited to 2 h, and very limited contact with ICSI, where only 1 sperm was injected into the oocyte thus not exposing the zona pellucida to any sperm. The patients were further subdivided into age groups of < or =39 or > or =40. SAB rates after frozen ET were also evaluated. The clinical pregnancy and SAB rates following fresh or frozen ET for conventional, ICSI, and short insemination techniques for the 2 age groups were comparable. These data question whether oligoasthenozoospermia may be a factor in causing SAB, and whether avoidance of contact with the zona pellucida by using ICSI can negate this effect. A larger study is needed.