COPENHAGEN — Early embryo transfer on the first day after fertilization may remedy certain in vitro fertilization failures due to poor embryo quality, researchers reported in a poster presented at the annual meeting of the European Society of Human Reproduction and Embryology.
A subset of patients with good ovarian stimulation, egg quality, and fertilization have embryos that stop developing or exhibit extended fragmentation by their second day in culture, said Olia Anastasiou of the Laboratoire de VIF et de Biologie de la Reproduction at Hôpital Tenon in Paris.
“We have patients like this, most of whom have had three trials of [in vitro fertilization] with really bad quality embryos. It's been a real question mark what to do for them,” she said in an interview.
Prolonging embryo culture to the blastocyst stage (day 5) for such patients is a risk that usually results in no surviving embryos to transfer, she explained.
Her team's hypothesis was that certain maternal proteins, which are normally responsible for preimplantation embryo development, were deficient in these patients, making their embryos unable to survive the culture conditions in vitro.
For this group, they investigated the benefit of early embryo transfer at the pronuclear stage, just 1 day after fertilization.
A total of 27 patients were initially included in the study. The average age of the patients was 35 years; all had experienced at least two in vitro fertilization [IVF] failures due to “drastically impaired” embryonic development. None had achieved a pregnancy despite normal parental karyotypes and sperm DNA fragmentation rates.
The patients had their third and fourth IVF cycles performed with transfer and cryopreservation of pronuclear-stage embryos. Eight clinical pregnancies were obtained, representing a pregnancy rate of 29% and an implantation rate of 14%.
Data now have been collected for 50 patients—15 of whom have become pregnant, for a pregnancy rate of 27%.
“We were surprised ourselves since between all of these patients we had performed more than 180 cycles with absolutely no pregnancy,” she said.
No pregnancies have yet been reported from the cryopreserved embryos.