Fresh vs frozen embryos: no difference in pregnancy rate in women without PCOS

Access to the full content of this site is available only to registered healthcare professionals. Register to read more


  • No difference in the rates of clinical pregnancy or live birth rate in infertile women without PCOS using fresh and frozen embryos during in vitro fertilization (IVF).

Why this matters 

  • Previously frozen embryos have been associated with fewer complications and better neonatal outcomes compared with fresh embryos.

Key results

  • 36.3% had ongoing pregnancy in the frozen-embryo group compared with 34.5% in the fresh-embryo group (P=.65).
  • Rates of implantation, clinical pregnancy, and live birth did not differ between groups.
  • Fewer small for gestational age babies (<10th percentile) were born in the frozen-embryo group compared with the fresh-embryo group (P=.01).

Study design

  • Single-center, randomized, control trial.
  • Women with infertility who were scheduled for IVF and did not have PCOS were included.
  • Frozen-embryo transfer (n=391) was compared with fresh-embryo transfer (n=391).
  • Primary outcome was ongoing pregnancy after the first transfer of embryos.
  • Funding: My Duc Hospital, Ho Chi Minh City, Vietnam.


  • Limited to a single center in Vietnam; results may not be generalizable.