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Many high-grade embryos selected for transfer according to their morphological evaluation were detected to have chromosomal abnormalities after aneuploidy screening for infertility by preimplantation genetic diagnosis (PGD). The aim of this study was to detect if there is any correlation between embryo quality and genetic status. The chromosomal status of the day three embryos was studied by multicolour fluorescence in-situ hybridization for chromosomes 13, 18, 21, X and Y. PGD was performed on 132 patients for 1107 embryos. The correlation between embryo quality and aneuploidy was analysed. The analysis showed that a large proportion of normal embryos (50.7%, n = 280) were grade I. In addition, a considerably high proportion of aneuploid embryos (36.1%, n = 83) were evaluated as grade I. There was a significant relationship between PGD results and embryo grades (P = 0.001). Of the 69 polyploid embryos, 21.7% were grade I and 37.8% were grade II. Of the 83 haploid embryos, 27.8% were grade I and 34.9% were grade II. Euploidy was positively related to morphological grade of embryo (P = 0.001). It was also possible for chromosomally abnormal embryos to have a good developmental potential, and they could be selected for embryo transfer unless the PGD procedure was applied.

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Natural life depends on biological rhythms that enable living creatures to thrive and survive. Biological rhythms or clocks allow species to adapt their physiological functions to external environmental changes. The environmental changes, creating a complex circadian (day) and circannual (year) rhythmicity, affect the whole organism, particularly the endocrine glands and the gonads. The hypothalamic-pituitary-gonadal axis is extremely susceptible to circannual rhythmicity, regulating the hormone levels (Santi et al., 2020). One of the most critical functions of annual hormone changes in nature is the optimisation of reproduction timing, thereby ensuring the highest survival chances of the offspring (Henkel et al., 2006; Roenneberg & Aschoff, 1990). Unlike other animal species, humans do not necessitate to set a season of fertility and can reproduce throughout the entire year. Although the human is not normally considered a seasonal breeder, many reports demonstrated the seasonal changes in gonadotropins, gonadal hormones and melatonin

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During the recent two decades, a remarkable drop in fertility rates has been noticed almost all over the world. A series of studies have showed that environmental factors had the primary role causing the observed adverse trends in the male reproductive health problems. Especially chlorinated hydrocarbons, for instance polychlorinated biphenyls (PCB) and pesticides, could mimic or antagonize the effects of steroid hormones, like estrogens and androgens and possibly interfering with male reproductive capacity. Organochlorine pesticides (OCPs) (i.e. p.p'-DDT, endosulfan...) and PCBs are widespread used chemicals in agriculture and industry for different purposes all over the world. Although direct evidence is lacking, theoretical considerations and epidemiological evidence implicate these compounds as potential hazards to human and wildlife reproductive health. For this purpose, in this study adipose tissue samples have provided from healthy males which were diagnosed as infertile men living in Ankara, Turkey at least for 5 years. Residual levels of OCPs (alpha-BHC, beta-BHC, gamma-BHC, HCB, Endosulfan I, II, p,p'-DDE, and p,p'-DDT) and seven major persistent PCB congeners (PCB 28, 52, 101, 118, 138, 153, and 180) were measured in 25 infertile men and 21 healthy men's adipose tissue samples by GC-ECD. Levels of OCPs and PCBs in adipose tissue of infertile men compared with those provided from controls. When the concentrations of each of the OCP were compared between the fertile and infertile groups, no statistical significance was obtained. Concentrations of each of the PCB congeners were compared between the fertile and infertile groups, no statistical significance was obtained (p > 0.05), except for 2,2',5,5'-Tetrachlorobiphenyl (PCB 52) (p = 0.032) and 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180) (p = 0.017).