Article 1 Endothelial Cells 1 Endothelial cells 1 Female 1 First trimester 1 Flow Cytometry 1 HUAEC 1 HUAEC cell line 1 HUVEC 1 Human placenta Humans 1 Isolation 1 Pregnancy 1 Pregnancy Trimester, First 1 Umbilical cord 1 blood 1 cell count 1 cell density 1 cell isolation 1 cell proliferation 1 cell size 1 cigarette smoking 1 controlled study 1 cytology 1 endothelium cell 1 female 1 first trimester pregnancy 1 flow cytometry 1 human 1 human cell 1