A policy of single embryo transfer (SET) reduces the risk of perinatal mortality in infants born as a result of IVF and ICSI. The conclusion emerged from an analysis of more than 50,000 births recorded in the Australian and New Zealand Assisted Reproduction Technology Database between 2004 and 2008, where the introduction of an SET policy has been associated with a reduction in overall perinatal mortality for IVF and ICSI babies.
Results of the analysis were presented here today at the annual meeting of ESHRE (European Society of Human Reproduction and Embryology) by Professor Elizabeth Sullivan from the Perinatal & Reproductive Epidemiology Research Unit of the University of New South Wales in Sydney, Australia. Professor Sullivan said that from a public health perspective "there is justification for advocating SET as first line management in assisted reproduction with the aim of minimising preventable perinatal deaths".
The study she described included 50,258 births which were of more than 20 weeks gestation and/or 400 grams birthweight following IVF and ICSI pregnancies. Total perinatal deaths were defined as the number of fetal deaths (stillbirths) plus the number of neonatal deaths (deaths that occur before 28 days after birth).
Analysis showed an overall perinatal mortality rate of 16.2 per 1000 births, representing 813 perinatal deaths during the study period (630 stillbirths and 183 neonatal deaths).
However, births following the transfer of two embryos had a significantly higher perinatal mortality rate than births following SET (19.1 per 1000 births and 13.2 per 1000 births). The risk of perinatal mortality for all births following two embryo transfer was 53% higher than those following SET. This difference was especially apparent in births following the transfer of fresh (and not frozen) embryos; births following the transfer of two fresh embryos had 74% higher risk of perinatal mortality than births following fresh SET.
Twins accounted for half the total neonatal deaths and one-third the perinatal deaths. Twins also had significantly higher perinatal mortality rate than singletons (27.8 per 1000 births and 12.4 per 1000 births). However, twins born from SET (ie, monozygotic) had a higher risk of perinatal mortality than those born from two embryo transfers.