TRANSFER OF CRYOPRESERVED-THAWED PREEMBRYOS IN A CYCLE USING EXOGENOUS STEROIDS WITHOUT PRIOR GONADOTROPIN-RELEASING-HORMONE AGONIST SUPPRESSION YIELDS FAVORABLE PREGNANCY RESULTS

We have analysed the use of a programmed cycle of administration of ex ogenous steroids without prior suppression with a gonadotrophin-releas ing hormone agonist (GnRHa) for the transfer of cryopreserved-thawed p reembryos. From July 1992 to June 1994, 199 cycles (162 patients) were studied, Pre-embryos had been previously cryopreserved at the pronucl ear stage using 1.5 M 1,2-propanediol as a cryoprotectant, Preparation of the endometrium was achieved in a step-up regime with transdermal oestradiol patches (0.1 to 0.4 mg), Progesterone in oil (50 mg i.m.) w as started on cycle day 13, Pre-embryos were thawed on day 14 and tran sferred on day 15 after evidence of survival and cleavage, The mean (/- SD) age of patients undergoing transfer was 35.4 +/- 4.3 years, The mean number of pre-embryos thawed was 4.7 +/- 1.8 with a mean of 3.3 +/- 1.4 pre-embryos being transferred, Eight of the cycles demonstrate d follicular development > 16 mm prior to thaw and transfer; however, these patients did not demonstrate a luteinizing hormone surge, Mean e ndometrial thickness on day 13 was 10.8 +/- 2.1 mm, Overall pregnancy rate was 29.2% (57/195), The ongoing or delivery rate was 16.1% (32/19 5), The rate of preclinical losses per transfer was 6.2% (12/195), Ove rall, the implantation rate was 6.2% (47/757), Thus, the use of a prog rammed cycle for cryopreserved embryo transfer yields favourable pregn ancy outcome and offers practical advantages to patients, Prior suppre ssion with a GnRHa is not necessary for endometrial preparation.