Huisman G J, Alberda A T, Leerentveld R A, Verhoeff A, Zeilmaker G H
Department of Obstetrics and Gynaecologie, Academic Hospital Rotterdam, Dijkzigt, The Netherlands.
Fertil Steril. 1994 May;61(5):970-1. doi: 10.1016/s0015-0282(16)56715-6.
Embryo transfer results after a 2 to 4 day period of embryo culture were compared. Two thousand two hundred ninety-seven ETs, performed in 1991 and 1992, were analyzed. Ongoing pregnancy rates after 2, 3, or 4 days of embryo culture were 23.3%, 21.9%, and 26.4%, respectively. Multiple pregnancy rates were 36.2%, 38.8%, and 32.6% per ongoing pregnancy for the three groups, respectively. The implantation rate of 73 cavitating morulae on day 4 was surprisingly high (41%) compared with that of other developmental stages. Transfer after 4 days of culture gives the ability to recognize embryos with a very high implantation potential.
