Frozen Embryo Transfer Lowers Risk of OHSS
New research comparing fresh and frozen embryo transfer by Shi, Y. et. al. (2018) has found that live birth rates are equivalent between the two types of embryo transfer but that frozen embryo transfer significantly lowers the risk of ovarian hyperstimulation syndrome (OHSS).
In this multi-centre randomised controlled trial, 2157 who were undergoing their first IVF were randomly allocated to receive either fresh or frozen embryo transfer. The live birth rate did not differ significantly between the two groups. However, frozen embryo transfer resulted in significantly lower risk of OHSS than fresh embryo transfer (0.6% vs 2.0% relative risk). The risk of other adverse maternal and neonatal outcomes did not differ significantly between the 2 groups.
For more details you can read the full article in The New England Journal of Medicine.