Impact of PCOS on early embryo cleavage kinetics.

This study investigated whether polycystic ovary syndrome (PCOS) affected early embryo development assessed by time-lapse analysis of embryo kinetics from fertilization to the blastocyst stage. This was a prospective cohort study of two pronuclei (2PN) embryos from 25 hyperandrogenic PCOS patients (110 2PN embryos), 26 normoandrogenic PCOS patients (140 2PN embryos) and 20 healthy, regularly cycling women (controls, 97 2PN embryos). Patients underwent the same baseline evaluation and the same ovarian stimulation from April 2010 to February 2013. Oocytes were fertilized by intracytoplasmic sperm injection and incubated in an EmbryoScope with pictures taken every 20 min in seven focal planes. Time to 2PN breakdown, first cleavage and cleavage to 3, 4, 5, 6, 7 and 8 cells, morula and blastocyst (t2, t3, t4, t5, t6, t7, t8, t(M), t(B)) were annotated. Differences in embryo kinetics between groups were assessed by mixed modelling. Compared with controls, embryos from hyperandrogenic PCOS patients were significantly delayed at 2PN breakdown, t2, t3, t4 and t7 but not at t5, t6, t8, t(M) or t(B). Embryos from hyperandrogenic PCOS women had developed slower from fertilization to the 8-cell stage compared with embryos from controls.

The impact of pronuclei morphology and dynamicity on live birth outcome after time-lapse culture.

STUDY QUESTION: Can the pronuclei (PN) morphology and the time of PN breakdown (PNB) predict the potential of embryos to result in live birth? SUMMARY ANSWER: In comparison to embryos resulting in no live birth, PNB occurred significantly later in embryos resulting in live birth and never earlier than 20 h 45 min. None of the tested scoring systems were shown to predict the live birth outcome in a time-lapse set-up. WHAT IS KNOWN ALREADY: The PN morphology is supported as a prominent embryo selection parameter in single light microscopy observations, although controversial results have been reported. STUDY DESIGN, SIZE, DURATION: This was a prospective study of 159 embryos, all of which were later transferred. The PN morphology of 46 embryos which resulted in live birth was compared with that of 113 embryos which resulted in no live birth. PARTICIPANTS, SETTING: From 1 March 2010 to 30 August 2011, 130 couples underwent fertility treatment by ICSI. Embryo culture was performed in a time-lapse set-up from fertilization to intrauterine transfer. PN morphological assessment was performed on every embryo replaced, using six different scoring systems at different times. MAIN RESULTS AND THE ROLE OF CHANCE: No embryo with PNB earlier than 20 h 45 min resulted in live birth. All six PN assessment models showed no significant distribution of scores (P = NS) between the live birth and no live birth groups at 16 h post-fertilization (PF), 18 h PF and 40 min before PNB. The outcomes of assessments changed significantly (P < 0.001) over time and the time of PNB was found to be the optimal stage to evaluate the PN morphology. LIMITATIONS, REASONS FOR CAUTION: The study includes only embryos reaching the 4-cell stage after ICSI, and transferred at 44 h PF. WIDER IMPLICATIONS OF THE FINDINGS: The PN morphology changes over time, indicating that the single light microscopy observation approach is deficient in comparison to time-lapse. Although the assessment of the PN morphology does not improve embryo selection, the timing of PNB should be included in embryo selection parameters.