The risk of perinatal mortality has decreased in infants born by the methods of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with the help of a policy of single embryo transfer (SET). This finding came from an analysis of the Australian and New Zealand Assisted Reproduction Technology Database with over 50,000 births recorded between 2004 and 2008, where IVF and ICSI babies have experienced a decrease in overall perinatal mortality with this SET policy.

Professor Elizabeth Sullivan from the Perinatal and Reproductive Epidemiology Research Unit of the University of New South Wales in Syndey, Australia, presented the outcome of the analysis on Wednesday, July 4th, 2012, at the annual meeting of the European Society of Human Reproduction and Embryology (ESHRE).

Regarding public health, Professor Sullivan said: “There is justification for advocating SET as first line management in assisted reproduction with the aim of minimizing preventable perinatal deaths.”

The study included 50,258 births from IVF and ICSI pregnancies, all being more than 20 weeks gestation and/or 400 grams birth weight. The number of fetal deaths (stillbirths) and neonatal deaths (deaths that occur before 28 days after birth) together equaled the total number of perinatal deaths.

Results showed an overall perinatal mortality rate of 16.2 per 1000 births. This meant that there were 813 perinatal deaths during the study period- 630 stillbirths and 183 neonatal deaths.

Births following single embryo transfer had a significantly lower perinatal mortality rate than births following the transfer of two embryos. Single embryo transfer had 13.2 deaths per 1000 births, while the two embryo transfer method had19.1 deaths per 1000 births, i.e., the two embryo transfer had a 53 percent higher chance of perinatal mortality than those using the SET method. Births resulting from the transfer of two fresh embryos had a 74 percent higher chance of death than births resulting from fresh SET, showing that the difference was more apparent in births from the transfer of fresh embryos that had not been frozen.

Twins unfortunately had a considerably higher perinatal mortality rate than single births – 27.8 deaths per 1000 births as oppose to 12.4 per 1000 births. On the other hand, twins born from SET (known as monozygotic) had a higher chance of perinatal mortality than those born from the transfer of two embryos. Twins were responsible for half the total neonatal deaths and one-third the perinatal deaths.

All babies born by assisted reproduction methods have shown a reduction in overall perinatal mortality in Australia and New Zealand, which is linked to the voluntary adoption of an IVF policy of SET, Professor Sullivan stated. She explained that this analysis justifies why women under the age of 35 should use single embryo transfer as a first choice fertility treatment for non-donor cycles.

Professor Sullivan went on to explain that there are bigger public health benefits from a SET policy:

“The number of embryos transferred per procedure is the major determinant of multiple pregnancy and multiple delivery, which contribute to an elevated risk of preterm birth and low birth weight, and its sequealae. These are risks in addition to those already faced by women being treated for infertility.

Australia and New Zealand have shown that in the right policy environment a voluntary change to SET practice is achievable.”

Sullivan concluded that the acceptance of single embryo transfers has been more dramatic in some other countries, especially where policy plans are associated with funding and have led to great change in practice without jeopardizing quality or safety.

Written by Sara Glynn (B.A.)