He Y, et al. - Researchers examined the influence of metabolic syndrome (MetS) on overall female fertility and in vitro fertilization (IVF) outcomes in polycystic ovary syndrome (PCOS) infertile women via performing a secondary analysis of a multicenter randomized trial in 1508 PCOS women, which originally compared live birth rate after fresh embryo transfer vs frozen embryo transfer (FET) (Frefro-PCOS). Four hundred ten (27.2%) of 1508 PCOS infertile women had MetS. Outcomes revealed longer infertility duration (4.0±2.2 vs 3.7±2.2) in patients with MetS compared to those without MetS. During ovarian stimulation, significantly higher and longer doses of Gn were required and lower peak estradiol level, less retrieved oocytes, available embryos, lower oocyte utilization rate and ovarian hyperstimulation syndrome (OHSS) were observed among those with MetS than those with non-MetS. Outcomes suggest a negative influence of PCOS with MetS on female fecundity along with an adverse effect on IVF cycle stimulation characteristics and clinical outcomes.