The problem of multiple pregnancies hangs like a millstone around the neck of ovulation induction and ovarian stimulation for IUI and for IVF/embryo transfer. Multiple pregnancies carry an increased risk of premature delivery (x5), perinatal morbidity and mortality and psychological (and financial) implications for the parents. In ovulation induction the predisposing factor is multiple follicular development as it is for gonadotrophin stimulation before IUI whereas in IVF/embryo transfer, it is purely a reflection of the number of embryos transferred into the uterus. The use of low-dose gonadotrophin protocols minimizes the risk of multiple pregnancies in ovulation induction and stimulation for IUI whereas in IVF/ embryo transfer, the high multiple pregnancy rate can be considerably reduced by employing a selective single embryo transfer (eSET) policy without seriously affecting pregnancy rates in suitable candidates especially when frozen/thawed embryos are utilized in subsequent cycles.
Elective single embryo transfer will hopefully be more widely adopted as methods for embryo selection improve as it is the obvious solution for the reduction of the present unacceptable multiple pregnancy rates.