In women who conceived with or without assisted reproduction, we evaluated endothelial function by EndoPAT [reactive hyperemia index (RHI)], circulating numbers of endothelial cells (CEC) and endothelial progenitor cells (EPC), and their function before during and after pregnancy. In vitro fertilization (IVF) pregnancies were stratified by method of conception and corpus luteum (CL) number-controlled ovarian stimulation (>1 CL) or programmed (0 CL) cycles and spontaneous singleton pregnancies (1 CL). We observed 1) comparable gestational decline of RHI in the three participant groups secondary to gestational rise of baseline preocclusion pulse-wave amplitude (PWA) incorporated into the RHI calculation by EndoPAT software; 2) progressive rise in "normalized" RHI throughout pregnancy (calculated by substituting prepregnancy baseline preocclusion PWA into the RHI equation), greater in spontaneous conception vs. IVF cohorts; 3) similar gestational increase of maximum PWA and time to maximum PWA after the ischemia stimulus among the three participant groups; 4) modest gestational increase of ischemia response (reactive hyperemia) in the spontaneous conception group and no change or significant decline, respectively, in women who conceived using programmed or controlled ovarian stimulation cycles; 5) enhanced basal nitric oxide production by early (primitive) outgrowth EPC during pregnancy in women who conceived spontaneously, but not through IVF; and 6) gestational increase in CEC in all three participant cohorts, more pronounced in women who conceived by IVF using programmed cycles. On balance, the evidence supported enhanced endothelial function during pregnancy in spontaneous conceptions but less so in IVF pregnancies using either controlled ovarian stimulation or programmed cycles.
Keywords: EndoPAT; corpus luteum; ischemia response; nitric oxide; reactive hyperemia index; vasodilation.