Surrogacy in Australia: implantation rates have implications for embryo quality and uterine receptivity.

Since the passage, in November 1995, of the ACT Substitute Parents Agreement Act, The Canberra Fertility Centre has added a true gestational carrier pregnancy programme to its established infertility and IVF services. Embryos generated are transferred as frozen-thawed embryos to the carrier in an average of 2.2 embryos per transfer. Between 1 January 1996 and 31 December 1999 the results of 49 frozen embryo transfers to 25 gestational carriers were compared with 849 frozen embryo transfers on a routine IVF programme. In the carrier group, the embryo implantation rate of 13.8% per embryo transferred is double that of an exactly comparable group of patients undergoing routine frozen-thawed embryo transfer on the same IVF programme and considerably higher than those reported in large series of frozen-thawed embryo transfers. Exclusion from the carrier pregnancy programme of patients with incipient ovarian failure results in an implantation rate of 16.7%, a clinical pregnancy rate of 29.0% and a live birth rate of 19.4% per embryo transfer procedure.