The investigators want to examine specific cardio-metabolic and cardiovascular parameters in women of subfertile couples. The investigators want to evaluate the prevalence of metabolic syndrome in all women who are assessed for subfertility compared to healthy parous women. Furthermore in the women with an unexplained subfertility or with (signs of) a decreased ovarian reserve the cardiovascular profile will be studied consisting of the uterine artery pulsatility index (PI) as measure of uterine perfusion, the plasma volume as measure of venous reserve capacity, the intima media thickness of the carotid arteries as proxy of chronic strain and the endothelial function, measured by flow mediated dilatation (FMD) of the brachial artery.