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Updated: Mar 3, 2026
Human Egg Maturity Assessment and Its Clinical Application
Published on: August 19, 2019
Is there any correlation between oocyte polarization microscopy findings with embryo time lapse monitoring in ICSI
Azita Faramarzi1, Mohammad Ali Khalili2, Azam Agha-Rahimi1
1Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Bouali Ave., Safaeyeh, Yazd, Iran.
Purpose:
The aim was to investigate the relationship between the presence of the meiotic spindle (MS) and zona pellucida (ZP) birefringence of MII oocytes with morphokinetics variables of derived embryos in ICSI setting.
Methods:
Using a polarization imaging system, the ZP birefringence and presence of MS were evaluated pre ICSI. Also, morphokinetics variables including time of second PB extrusion (tPB2), time of pronuclei appearance (tPNa), time of pronuclei fading (tPNf), time of two to eight discrete cells (t2-t8) ECC1 (t2-tPB2), cc2a (t3-t2), S2 (t4-t3) and S3 (t8-t5) as well as irregular cleavage events of 368 embryos were analyzed with time lapse monitoring (TLM).
Results:
t5 occurred earlier in high birefringent ZP (HB-ZP) compared with low birefringent oocytes (LB-ZP; p = 0.001). In addition, t2 happened later in invisible MS compared to visible MS oocytes (p = 0.013). There were significantly lower rates of cell fusion (Fu) in oocytes with HB-ZP and also the Fu and trichotomous mitoses (TM) together in visible MS oocytes (p = 0.005, p = 0.001 and p = 0.001, respectively).
Conclusions:
Both t2 and t5 timings and irregular cleavage events of embryos were correlated with ZP birefringence and MS status, respectively. So, combining the information from both oocyte polarization microscopy imaging and embryo TLM can be a useful tool for single embryo transfer (SET) program.
Insights
Oocyte zona pellucida (ZP) birefringence and meiotic spindle (MS) presence correlate with embryo development timings and irregular cleavage. Combining these insights aids single embryo transfer (SET) success.
Area of Science:
- Reproductive biology
- Embryology
- In vitro fertilization (IVF)
Background:
- Oocyte quality is crucial for successful IVF.
- Meiotic spindle (MS) and zona pellucida (ZP) birefringence are indicators of oocyte health.
- Predicting embryo development potential is key for single embryo transfer (SET).
Purpose of the Study:
- To investigate the relationship between MS presence and ZP birefringence in MII oocytes.
- To correlate these oocyte characteristics with morphokinetic variables of derived embryos during intracytoplasmic sperm injection (ICSI).
Main Methods:
- A polarization imaging system assessed ZP birefringence and MS presence pre-ICSI.
- Time-lapse monitoring (TLM) analyzed morphokinetic variables of 368 embryos.
- Key variables included timings of second polar body extrusion (tPB2), pronuclei appearance (tPNa), pronuclei fading (tPNf), and cell cleavage stages (t2-t8).
Main Results:
- Earlier t5 timing was observed in oocytes with high ZP birefringence (HB-ZP) versus low ZP birefringence (LB-ZP).
- Later t2 timing occurred in oocytes with invisible MS compared to visible MS.
- Lower rates of cell fusion (Fu) were noted in HB-ZP oocytes; Fu and trichotomous mitoses (TM) were lower in visible MS oocytes.
Conclusions:
- Embryo developmental timings (t2, t5) and irregular cleavage events are linked to ZP birefringence and MS status.
- Integrating oocyte polarization imaging with embryo TLM can enhance SET programs.
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