title: Relationship between cord vein normeperidine and time.
mesh_terms: D005260:Female; D005312:Fetal Blood / Q000032:analysis*; D006801:Humans; D008614:Meperidine / Q000031:analogs & derivatives* / Q000097:blood; D011247:Pregnancy; D013997:Time Factors; D014471:Umbilical Veins
chemical_list: D008614:Meperidine