There are several factors, both intrinsic and extrinsic, that can influence embryo quality:
- Advanced maternal age
- Severe male factor
- Polycystic ovary syndrome
- Stimulation protocols
- Cultivation conditions
That being said, it is difficult to know the specific cause that could affect a particular case in women with good prognosis and good reproductive health.
Suggested for you: Classification of Embryos According to Their Quality.