title: Effect of gravidity and parity on the parameters used in serum screening for trisomy 21.
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood*; D004314:Down Syndrome / Q000175:diagnosis*; D004964:Estriol / Q000097:blood*; D005260:Female; D006801:Humans; D010298:Parity; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol