N Engl J Med 2018; 378:137-147 (IF 79.258) – 2018-01-11
Lan N. Vuong1,2, Vinh Q. Dang2, Tuong M. Ho2,3, Bao G. Huynh2, Duc T. Ha4, Toan D. Pham2, Linh K. Nguyen2, Robert J. Norman5, and Ben W. Mol5,6
Published: January 11, 2018
- Department of Obstetrics and Gynecology, University of Medicine and Pharmacy at Ho Chi Minh City (L.N.V.),
- IVFMD, My Duc Hospital (L.N.V., V.Q.D., T.M.H., B.G.H., T.D.P., L.K.N.),
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University (T.M.H.), Ho Chi
- National Hospital of Can Tho, Can Tho (D.T.H.) — all in Vietnam;
- Robinson Research Institute, Department of Medicine (R.J.N.,B.W.M.), Fertility South Australia (R.J.N.),
- South Australian Health and Medical Research Institute (B.W.M.) — all in Adelaide, SA, Australia
Among women who are undergoing in vitro fertilization (IVF), the transfer of frozen embryos has been shown to result in a higher rate of live birth than the transfer of fresh embryos in those with infertility associated with the polycystic ovary syndrome. It is not known whether frozen-embryo transfer results in similar benefit in women with infertility that is not associated with the polycystic ovary syndrome.
We randomly assigned 782 infertile women without the polycystic ovary syndrome who were undergoing a first or second IVF cycle to receive either a frozen embryo or a fresh embryo on day 3. In the frozen-embryo group, all grade 1 and 2 embryos had been cryopreserved, and a maximum of two embryos were thawed on the day of transfer in the following cycle. In the fresh-embryo group, a maximum of two fresh embryos were transferred in the stimulated cycle. The primary outcome was ongoing pregnancy after the first embryo transfer.
After the first completed cycle, ongoing pregnancy occurred in 142 of 391 women (36.3%) in the frozen-embryo group and in 135 of 391 (34.5%) in the fresh-embryo group (risk ratio in the frozen-embryo group, 1.05; 95% confidence interval [CI], 0.87 to 1.27; P=0.65). Rates of live birth after the first transfer were 33.8% and 31.5%, respectively (risk ratio, 1.07; 95% CI, 0.88 to 1.31).
Among infertile women without the polycystic ovary syndrome who were undergoing IVF, the transfer of frozen embryos did not result in significantly higher rates of ongoing pregnancy or live birth than the transfer of fresh embryos. (Funded by My Duc Hospital; ClinicalTrials.gov number, NCT02471573.)