does women’s age influence zona pellucida birefringence of metaphase ιι oocytes in in-vitro maturation program?

background: in vitro maturation (ivm) is a promising treatment option for certain infertile women. nowadays, with the aid of polscope, it has become possible to evaluate zona pellucida (zp) characteristics as a parameter of oocyte quality. moreover, quality of oocytes can be influenced by many factors, such as patient’s age. the polscope system is a non-invasive technique to assess birefringent structures such as the meiotic spindle and zp in living oocytes. objective: the aim was to determine the influence of the woman's age on zp birefringence, a sign of oocyte quality, and morphology of in-vitro matured human oocytes using non-invasive polarized light (polscope) microscopy. materials and methods: zp birefringence and morphology were determined in 105 retrieved oocytes from 58 women undergoing icsi in two age groups (≥30 years and <30 years). the immature oocytes were selected and after ivm, the quality of metaphase ιι (mii) oocytes was assessed. the oocytes abnormalities were classified as intracytoplasmic and extracytoplasmic abnormalities. results: oocyte maturation rates were significantly reduced in ≥30 year’s women (56%) in comparison with other age group (80.7%). in addition, the zp birefringence was significantly higher in mii oocytes in the younger group compared with the older group (76.2% vs. 38.1%; p=0.00). following morphologic assessment, the rates of oocytes with extracytoplasmic (p=0.02) and both abnormalities (extra- and intracytoplasmic) (p=0.01) were higher in aged versus the younger women. conclusion: there was a positive relationship between advanced maternal age with decreased zp birefringence and oocyte morphological quality in in-vitro matured human oocytes.