TREATMENT OF MALE-INFERTILITY AND IDIOPATHIC FAILURE TO FERTILIZE IN-VITRO WITH UNDER ZONA INSEMINATION AND DIRECT EGG INJECTION

OBJECTIVE: Failure to fertilize eggs in vitro may be countered by micr omanipulation of gametes to place selected spermatozoa underneath the zona pellucida of the egg or directly into the egg, thereby improving chances of fertilization and production of viable embryos. Analysis of our clinical data for assisted fertilization was undertaken to assess those factors of relevance in this therapy, and a description of our procedures are given. STUDY DESIGN: Retrospective analysis of 85 cycle s (73 couples) of in vitro fertilization and embryo transfer performed at a private infertility clinic, in which micromanipulation for assis ted fertilization was used to overcome either severe male factor infer tility or idiopathic failure to fertilize, was performed. RESULTS: In 60 cycles where only embryos from under zona insemination were availab le for uterine transfer, 15 singleton and two twin pregnancies occurre d (28.3% viable pregnancy rate per transfer, 14.1% embryonic implantat ion). In 14 of these cycles embryos arose only after repeated under zo na insemination adding more spermatozoa; this accounted for four of th e singleton and one of the twin pregnancies (38.5% pregnancy rate, 22. 2% embryonic implantation). No embryos arose from partial zona dissect ion performed in five cycles on sibling eggs. However, in 16 cycles co nventional insemination yielded fertilization in six cycles, and mixed transfer of these embryos and sibling embryos from under zona insemin ation gave rise to one pregnancy from four transfers (pregnancy rate 2 5%, embryonic implantation 7.1%). Likewise, in nine cycles donor sperm atozoa yielded fertilization in eight cycles, and mixed transfer with sibling embryos fertilized by under zona insemination with partner's s permatozoa gave rise to two pregnancies from five transfers (pregnancy rate 40%, embryonic implantation 15.8%). Fertilization and pregnancy rates did not differ whether couples suffered either from male factor infertility or from previous idiopathic fertilization failure. Direct egg injection of a single spermatozoon into 105 eggs gave an 88.6% egg survival and 32.3% fertilization. Mixed transfers with sibling embryo s from conventional and under zona insemination yielded one triplet, o ne twin, and three singleton pregnancies. CONCLUSIONS: Overall, a 24.7 % (21/85) viable pregnancy rate per cycle initiated occurred when only embryos from assisted fertilization were available. This strongly ind icates that assisted fertilization made a real contribution in cases w here either insufficient spermatozoa were available for conventional i nsemination or in cases where previous fertilization failure had arise n. The wide range of seminal parameters were found to be unhelpful in defining chances of success with assisted fertilization.