Preeclampsia,a complication of pregnancy characterized by hypertension and proteinuria,has been found to reduce the subsequent risk for breast cancer in female offspring.As this protective effect could be due to exposure to preeclampsia-specifc proteins during intrauterine life,the proteomic profles of umbilical cord blood plasma between preeclamptic and normotensive pregnancies were compared.Umbilical cord plasma samples,depleted of 14 abundant proteins,were subjected to proteomic analysis using the quantitative method of nanoACQUITY ultra performance liquid chromatography–mass spectrometry with elevated energy mode of acquisitionE(NanoUPLC-MSE).Sixty-nine differentially expressed proteins were identifed,of which 15 and 6proteins were only detected in preeclamptic and normotensive pregnancies,respectively.Additionally,expression of 8 proteins(gelsolin,complement C5,keratin type I cytoskeletal 10,pigment epithelium-derived factor,complement factor B,complement component C7,hemoglobin subunit gamma-2 and alpha-fetoprotein)were up-regulated in preeclampsia with a fold change of P2.0 when compared to normotensive pregnancies.The identifcation of alpha-fetoprotein in preeclamptic umbilical cord blood plasma supported the validity of this screen as alpha-fetoprotein has anti-estrogenic properties and has previously been linked to preeclampsia as well as a reduced breast cancer risk.The fndings of this pilot study may provide new insights into the mechanistic link between preeclampsia and potentially reduced breast cancer susceptibility in adult life. Preeclampsia, a complication of pregnancy characterized by hypertension and proteinuria, has been found to reduce the subsequent risk for breast cancer in female offspring. As this protective effect could be due to exposure to preeclampsia-specifc proteins during intrauterine life, the proteomic profles of umbilical cord blood plasma between preeclamptic and normotensive pregnancies were compared. Umbilical cord plasma samples, depleted of 14 abundant proteins, were subjected to proteomic analysis using the quantitative method of nanoACQUITY ultra performance liquid chromatography-mass spectrometry with elevated energy mode of acquisition E (NanoUPLC-MSE ) Sixty-nine differentially expressed proteins were identified, of which 15 and 6 proteins were were detected in preeclamptic and normotensive pregnancies, respectively. Additionally, expression of 8 proteins (gelsolin, complement C5, keratin type I cytoskeletal 10, pigment epithelium-derived factor , complement factor B, complement component C7, hemoglobin subunit gamma-2 and alpha-fetoprotein were up-regulated in preeclampsia with a fold change of P2.0 when compared to normotensive pregnancies. identifiable of alpha-fetoprotein in preeclamptic umbilical cord blood plasma supported the validity of this screen as alpha- fetoprotein has anti-estrogenic properties and has previously been linked to preeclampsia as well as a reduced breast cancer risk. fndings of this pilot study may provide new insights into the mechanistic link between preeclampsia and potentially reduced breast cancer susceptibility in adult life.