A new study published last week in the New England Journal of Medicine suggested that previously frozen and then thawed embryos might lead to higher live-birth rates than fresh embryos.
In a randomized trial of 1,508 women aged 20 to 34 with polycystic ovary syndrome undergoing in vitro fertilization for the first time, researchers found that 49.3 percent of those who used frozen embryos successfully gave birth, compared with 42 percent who used fresh embryos.
Led by Shandong University deputy head Chen Zijiang, who specializes in reproductive studies, the research team collected data from 14 reproductive centers throughout China from 2013 to last year. All participants were followed throughout their pregnancy.
The study also suggested that frozen embryos might lead to an increase in a baby's weight at birth.

http://m.chinadaily.com.cn/en/2016-08/18/content_26523654.htm?from=singlemessage&isappinstalled=0