AN IVF FALLACY - MULTIPLE PREGNANCY RISK IS LOWER FOR OLDER WOMEN

Introduction: Multiple pregnancy is one of the most important and prev entable complications of in vitro fertilization (IVF) and embryo trans fer The general clinical practice in many IVF clinics is to transfer f our or five embryos to older women if available, since pregnancy rates are lower in women older than 35 years of age. However it is not clea r whether the risk for multiple pregnancy is also lower. Objective: Ou r objective was to investigate whether transferring a higher number of embryos actually improves pregnancy outcome in older women, without i ncreasing the risk for multiple pregnancy and to investigate other fac tors that may affect the occurrence of multiple pregnancy. Setting: Th e setting was university-based IVF program at The Toronto Hospital.Des ign: The design was a retrospective case series. Patients and Methods: The outcome of 1116 IVF cycles between January 1992 and December 1993 was investigated according to different age groups. Main Outcome Meas ure: The main outcome measure was multiple pregnancies. Results: Seven ty multiple pregnancies resulted from a total of 242 pregnancies Overa ll pregnancy and multiple pregnancy rates were inversely correlated wi th age. However; when the data were adjusted for the number of embryos transferred, this trend disappeared. The result of multiple regressio n analysis showed that the multiple pregnancy rare was higher without improving the pregnancy rate when the number of embryos transferred ex ceeded three, regardless of the age of the patients, especially when m ore embryos were available than the number of transferred ones. Conclu sions: The number of embryos transferred should be limited to a maximu m of three regardless of the age of patients, to reduce the high frequ ency of multiple gestations in an IVF program.