title: The association between fetal sex and preterm birth in twin pregnancies.
authors.forename: Ihab M
authors.initials: IM
authors.lastname: Usta
authors.forename: Anwar H
authors.initials: AH
authors.lastname: Nassar
mesh_terms: D005260:Female; D005333:Fetus; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012737:Sex Factors; D014427:Twins