Understanding the likelihood of a live birth is important for fertility treatment planning, particularly when one cycle fails and further treatment may be contemplated. This study aims to estimate the chance of live birth among gestational surrogates undergoing altruistic surrogacy arrangements between 2009 and 2016 in Victoria, Australia. A total of 81 gestational surrogates with 170 embryo transfer cycles were included. Of the 170 embryo transfer cycles, the majority were single embryo transfers (SETs; 97.1%), using frozen/thawed embryos (97.6%) which had been fertilized by intracytoplasmic sperm injection (77.6%). The cumulative live birth rate was 23.5% (95% CI, 15.6-33.8%) after the first cycle and increased to 50.6% (95% CI, 40.0-61.2%) after the sixth cycle. Of the 41 deliveries, 40 were singletons and one was a twin delivery. Two of the 42 deliveries were preterm, two were low birthweight and one was small for gestational age. The findings imply that surrogacy treatment can be offered up to six consecutive embryo transfer cycles to gestational surrogates. SET is encouraged in surrogacy practice to improve perinatal outcomes. These estimates can be used in counselling and decision-making for intended parents and gestational surrogates to continue a surrogacy treatment and informing public policy on assisted reproductive technology treatment.
Keywords: Altruistic; assisted reproductive technology; cumulative live birth rate; gestational carrier; surrogacy; surrogates.