Long-term follow-up of cryopreserved hemi-ovary autografts in ewes: pregnancies, births, and histologic assessment.

OBJECTIVE To evaluate a 2-year follow-up of cryopreserved hemi-ovary autografts in ewes. DESIGN Animal study. SERTTING: University fertility center, Hospices Civils de Lyon; Ecole Nationale Vétérinaire de Lyon, INSERM U 418 Hocaron;pital Debrousse, Lyon; and Hôpital Edouard Herriot, Lyon, France. PATIENT(S) Grivette ewes. INTERVENTION(S) Recently we reported four pregnancies and six live births after transplantation of frozen-thawed hemi-ovary in six different ewes. The four remaining ewes were monitored for 2 years. After the last birth, the autografted ovary was removed in each ewe during a final laparotomy. The entire grafted ovary was sliced to estimate the remaining primordial follicle population 2 years after grafting. MAIN OUTCOME MEASURE(S) Uterine ultrasound scanning was performed to diagnose pregnancy. Histological assessment of the grafted ovary was performed after delivery. RESULT(S) The four remaining ewes began new gestations. For two of them, this was a second gestation obtained more than 2 years after the autograft. These two ewes delivered male lambs, which died immediately after delivery because of distocia. The lambs were both oversized for gestational age; autopsy found no malformation. A twin pregnancy of a healthy male and a healthy female occurred in May 2002, and a singleton male was born in February 2002. All grafted ovaries showed drastic reduction in follicle population. CONCLUSION(S) Frozen-thawed ovary autograft allowed recovery of fertility a very long time after the procedure despite a drastic reduction in the total number of follicles.