Author(s): Demoulin A, Jouan C, Gerday C, Dubois M
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Abstract After in-vitro fertilization, 2161 supernumerary embryos were frozen with 1,2-propanediol and sucrose as cryoprotectants at either pronucleate or multicellular (2-6 blastomeres) stages. By the end of March 1990, 494 pronucleate stage embryos and 492 multicellular stage embryos had been thawed and 54 and 47\% of them, respectively were considered suitable for transfer. Ongoing pregnancy and implantation rates were 17.9 and 10.7\%, respectively for embryos frozen at the pronucleate stage and 5.5 and 4.7\% for embryos frozen at the multicellular stage. Ovarian stimulation with human menopausal gonadotrophin (HMG) after pharmacological hypophysectomy with a gonadotrophin releasing hormone agonistic analogue (GnRHa) using a long protocol permitted us to freeze significantly more embryos per cycle (7.2 +/- 4.1) than stimulation with HMG and GnRHa in a short protocol (4.7 +/- 3.4) or stimulation with clomiphene citrate (CC) and HMG (2.7 +/- 1.9). Ongoing pregnancy rates after transfer during the stimulated cycles were similar for the three types of treatment (27.1, 27.3 and 32.1\%, respectively). However, ongoing pregnancy rates after frozen-thawed embryo transfers were significantly higher when originating from GnRHa + HMG treatments (14.3 and 14.8\%, respectively for long and short protocols) than when originating from CC + HMG treatment (5.6\%). Embryo cryopreservation has permitted the ongoing pregnancy rate to increase from 28.4 to 36.9\% (P less than 0.01) even though more than half of the embryos have not been thawed. We conclude that embryos obtained after stimulation with GnRHa + HMG and frozen at the pronucleate stage are more likely to result in a pregnancy.
This article was published in Hum Reprod
and referenced in Journal of Clinical Case Reports