title: HIV risk higher for first-born twins.
authors.forename: J
authors.initials: J
authors.lastname: Palca
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000635:transmission*; D001722:Birth Order; D002585:Cesarean Section; D036861:Delivery, Obstetric; D004200:Diseases in Twins; D005260:Female; D015658:HIV Infections / Q000635:transmission*; D006801:Humans; D007743:Labor, Obstetric; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000503:physiopathology; D012307:Risk Factors