Notably, a recent report suggests hCG stimulates LHCGR expression in lymphocyte during controlled ovarian stimulation and is linked to improved implantation [32] On the other hand, undetectable to low circulating sLHCGR/LH-sLHCGR might reflect reduced hormonal activation and down regulation of sLHCGR synthesis as observed in Down's syndrome placenta [33,34]. Here, PLOD1 is linked to Down syndrome.