Impact of early cleaved zygote morphology on embryo development and in vitro fertilization-embryo transfer outcome: a prospective study.
ABSTRACT To evaluate the impact of the first division morphology on embryo development and IVF-embryo transfer outcome.
Teaching hospital, France.
All zygotes from 201 couples were checked for early cleavage. We defined as "even," early cleaved (EC) zygotes with 2 cells of even size; as "uneven," EC zygotes with 2 cells of uneven size; and as "fragmented," EC zygotes with more than 20% fragmentation rate. Day 2 embryo quality was assessed as "top" embryo or "non-top," with the evaluation of multinucleated blastomeres.
Day 2 embryo quality, pregnancy and implantation rates.
Among EC zygotes, 59.1% were even, 13.0% were uneven, and 27.9% were fragmented. Even EC yielded more "top" embryos and less multinucleated blastomere embryos than uneven EC (77.0% vs. 46.3%) and fragmented EC (77.0% vs. 13.9%). The 125 double embryo transfers that comprised at least one embryo derived from even EC zygote led to higher pregnancy rate (PR) (64.0% vs. 43.4%) and implantation rate (42.0% vs. 27.6%) compared to the 76 double embryo transfers with embryos derived from breakdown or 2PN zygotes.
The morphology of the early cleaved zygote is involved in embryo development. Evaluation of this morphology is an effective and valuable method of assessing the embryo quality.
- [show abstract] [hide abstract]
ABSTRACT: Time-lapse observation presents an opportunity for optimizing embryo selection based on morphological grading as well as providing novel kinetic parameters, which may further improve accurate selection of viable embryos. The objective of this retrospective study was to identify the morphokinetic parameters specific to embryos that were capable of implanting. In order to compare a large number of embryos, with minimal variation in culture conditions, we have used an automatic embryo monitoring system. Using a tri-gas IVF incubator with a built-in camera designed to automatically acquire images at defined time points, we have simultaneously monitored up to 72 individual embryos without removing the embryos from the controlled environment. Images were acquired every 15 min in five different focal planes for at least 64 h for each embryo. We have monitored the development of transferred embryos from 285 couples undergoing their first ICSI cycle. The total number of transferred embryos was 522, of which 247 either failed to implant or fully implanted, with full implantation meaning that all transferred embryos in a treatment implanted. A detailed retrospective analysis of cleavage times, blastomere size and multinucleation was made for the 247 transferred embryos with either failed or full implantation. We found that several parameters were significantly correlated with subsequent implantation (e.g. time of first and subsequent cleavages as well as the time between cleavages). The most predictive parameters were: (i) time of division to 5 cells, t5 (48.8-56.6 h after ICSI); (ii) time between division to 3 cells and subsequent division to 4 cells, s2 (≤ 0.76 h) and (iii) duration of cell cycle two, i.e. time between division to 2 cells and division to 3 cells, cc2 (≤ 11.9 h). We also observed aberrant behavior such as multinucleation at the 4 cell stage, uneven blastomere size at the 2 cell stage and abrupt cell division to three or more cells, which appeared to largely preclude implantation. The image acquisition and time-lapse analysis system makes it possible to determine exact timing of embryo cleavages in a clinical setting. We propose a multivariable model based on our findings to classify embryos according to their probability of implantation. The efficacy of this classification will be evaluated in a prospective randomized study that ultimately will determine if implantation rates can be improved by time-lapse analysis.Human Reproduction 08/2011; 26(10):2658-71. · 4.67 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: OBJECTIVE: To evaluate embryos with direct cleavage (≤5 hours) from two to three cells (DC2-3) and correlate this morphokinetic parameter to implantation and ongoing pregnancy. DESIGN: Clinical multicenter retrospective study. SETTING: Private in vitro fertilization (IVF) centers. PATIENT(S): From three clinics, a total of 979 treatments including 5,225 embryos using autologous or donated oocytes, of which 1,659 embryos were transferred. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Clinical pregnancy confirmed by ultrasound in week 7. RESULT(S): Of the total embryo cohort, 715 (13.7%) underwent direct cleavage from two to three cells, 1,659 embryos were transferred to recipients, and 109 of the transferred embryos cleaved directly from two to three cells (6.6%). Only one DC2-3 embryo was known to result in a clinical pregnancy (1%) and 80 (73.4%) DC2-3 embryos did not implant. Of the 1,550 embryos transferred not showing DC2-3, 203 embryos were from treatments with 100% implantation (13.1%), and 804 (51.8%) embryos did not implant. The known implantation rate of DC2-3 embryos was statistically significantly lower than for embryos with a normal cleavage pattern (1.2% vs. 20.2%, respectively). CONCLUSION(S): Embryos with DC2-3 had a statistically significantly lower implantation rate than embryos with a normal cleavage pattern, suggesting that rejection of these embryos for transfer could improve the implantation rate.Fertility and sterility 08/2012; · 3.97 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Incorporation of time-lapse imaging in the field of IVF has provided much information about embryo development. The combination of the embryo appearance (morphology) and the importance of when and how the cellular processes that lead to this appearance occur (kinetics) are now integrated into the unique concept of morphokinetics. At present, efforts are focused on using this information to improve embryo selection and existing success rates without losing sight of the ever-present objective of implementing a single ET strategy to avoid multiple gestations. Several investigative groups have identified predictive morphokinetic variables for embryo viability and implantation potential. Promising supplementary models of embryo selection based on time-dependent markers have been proposed and are currently being verified in prospective trials. Pending further results of these studies that confirm the clinical validity of time-lapse imaging, the present article tries to summarize the studies conducted to date to take stock of what has been done and the prospects that are emerging from this technology.Fertility and sterility 02/2013; · 3.97 Impact Factor