title: Is the natural twinning rate now stable?
authors.affiliation: ICRF General Practice Research Group, Institute of Health Sciences, Headington, Oxford.
authors.forename: M F
authors.initials: MF
authors.lastname: Murphy
authors.forename: K
authors.initials: K
authors.lastname: Hey
authors.forename: D
authors.initials: D
authors.lastname: Whiteman
authors.forename: M
authors.initials: M
authors.lastname: O'Donnell
authors.forename: B
authors.initials: B
authors.lastname: Willis
authors.forename: D
authors.initials: D
authors.lastname: Barlow
mesh_terms: D017677:Age Distribution; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D017533:Marital Status / Q000706:statistics & numerical data; D008423:Maternal Age; D010062:Ovulation Induction / Q000706:statistics & numerical data* / Q000639:trends; D011159:Population Surveillance; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D012099:Reproductive Techniques / Q000706:statistics & numerical data* / Q000639:trends; D014852:Wales / Q000453:epidemiology