The risk of spermatid injection into an electrically stimulated oocytes. Reproductive health study on 251 new born babies

Abstract

OBJECTIVE: To overcome the low fertilization rate following conventional intracytoplasmic spermatid injection and the need for repeated testicular biopsies, we carried out spermatid cryopreservation and electrical stimulated oocyte activation. In this report we detail the clinical health findings of 251 babies (female: male =141:110) conceived following the use of this technique at our facility. DESIGN: Restrospective evaluation of health of babies following spermatid injection. MATERIALS AND METHODS: 763 non-obstructive azoospermic men whose spermatogenesis had been arrested at the early or late stage spermatid level had participated in a total of 1889 treatment cycles. Each spermatogenic cell suspension was transferred into a sampling tube containing cryoprotectant (1.6mol/l ethylene glycol with 0.2mol/l sucrose) . Freezing was carried out from -7 oC to -30oC at a rate of -0.3oC/min. Each straw was exposed to air and then immediately inserted into a 30 oC water bath. The cryoprotectant was removed in a stepwise fashion. Oocytes were transferred to a 295μM mannitol solution containing 0.1μM of CaCl2 and 0.05μM MgCl2, and then stimulated with an alternating current of 2V/cm at 1MHz for 8s followed by a single 1.2kV/cm pulse of direct current for 99μs. Individual spermatids were drawn into an injection pipette and the spermatid nucleus along with a small amount of cytoplasm was injected into an ooplasm. RESULTS: 1. The pregnancy and abortion rates for early and late stage spermatids were 16.0% (163/1021), 30.1% (49/163), and 20.4% (176/878), 27.2% (48/176) respectively. 2. One case of anal atresia and one case of mental retardation (early spermatid origin) were found among the 251 babies. 3. In 83 cases, cytogenetic chromosomal analysis was performed on fetal cells obtained through amniocentesis, which resulted in one paternally-inherited abnormal karyotype. CONCLUSIONS: we found that this technique did not increase the risk of developing unhealthy babies more than that following unassisted natural conception.