Clinical aspects of a successful embryo cryopreservation programme from IVF cycles in Singapore General Hospital

An analysis in November 1991 showed a successful cryopreservation programme between May 1989 and October 1991 in Singapore General Hospital. This programme has resulted in 9.1% more pregnancies in addition to those from conventional in-vitro fertilisation (IVF) methods, increasing pregnancy rates during the same period, from 27.8% per IVF cycle to 36.9% per cycle. The current policy is to transfer 3 fresh embryos in the IVF cycle and freeze the remainder using a modified Testart's method. Clinical factors that influence the success rate include the number of embryos transferred, stage of development of embryos and genital tract infections. Age of patient and grade of embryos did not seem to have affected pregnancy rates. Patients with anovulatory cycles enjoy similar pregnancy rates using a regulated cycle regime for frozen-thawed embryo transfer.