Influence of different oocyte insemination techniques on early and late morphokinetic parameters Retrospective analysis of 500 time lapse monitored blastocysts
In vitro fertilization–fertilized embryos developed with a 1.5-hour delay, which disappeared after standardization to pronuclear fading, thus permitting the joint analysis of standard IVF- and ICSI-fertilized embryo cohorts.
Daniel Bodri, M.D., M.Sc., Ph.D., Takeshi Sugimoto, M.Sc., Jazmina Yao Serna, M.Sc., Masae Kondo, B.Sc., Ryutaro Kato, B.Sc., Satoshi Kawachiya, M.D., Tsunekazu Matsumoto, M.D., Ph.D.
Volume 104, Issue 5, Pages 1175-1181
To determine how standard IVF vs. intracytoplasmic sperm injection (ICSI) fertilization influences early and late morphokinetic parameters during prolonged embryo culture.
Five-hundred expanded blastocysts that were monitored in a time-lapse monitoring incubator were analysed retrospectively. Early (pronuclear fading [PNf], t2–t9) and late (start of blastulation, expanded blastocyst) morphokinetic variables were scored according to published consensus criteria.
Private infertility clinic.
A total of 209 consecutive infertile patients (mean ± SD age, 38.4 ± 4 years; range, 28–47 years) undergoing 238 natural IVF/minimal ovarian stimulation cycles during 2012–2014.
Minimal ovarian stimulation, oocyte retrieval, fertilization with standard IVF or ICSI, prolonged embryo culture in a time-lapse monitoring incubator.
Main Outcome Measure(s):
Differences in morphokinetic parameters according to insemination techniques.
In total, 29% and 71% of the whole cohort was fertilized with standard IVF and ICSI, respectively. During early cleavage stages (PNf to t4) there was a statistically significant delay (+1.5 to +1.1 hours) among IVF-fertilized embryos. By contrast, at the expanded blastocyst stage IVF-fertilized embryos showed faster development (−3.3 to −4.1 hours). After normalizing to the time point of PNf, differences in cleavage-stage parameters disappeared, but those at all blastocyst stages increased even further in favor of IVF-fertilized embryos (−3.2 to −5.7 hours).
The observed 1.5-hour time difference between standard IVF- and ICSI-fertilized embryos is an artificial phenomenon. At the blastocyst stages, however, genuine timing differences arise between IVF- and ICSI-fertilized embryos, possibly related to their different quality. Normalization to a common time point permits the joint analysis of IVF- and ICSI-fertilized embryos, thus increasing the size of studied cohorts.