title: Twinning rates.
authors.forename: M
authors.initials: M
authors.lastname: Murphy
authors.forename: K
authors.initials: K
authors.lastname: Hey
mesh_terms: D001723:Birth Rate / Q000639:trends*; D004739:England; D005260:Female; D006801:Humans; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D014429:Twins, Dizygotic / Q000706:statistics & numerical data*; D014430:Twins, Monozygotic / Q000706:statistics & numerical data*; D014852:Wales