Maternal characteristics of women having twin pregnancies.
D000328:Adult; D000367:Age Factors; D001827:Body Height; D001835:Body Weight; D004739:England; D005260:Female; D006801:Humans; D008423:Maternal Age; D009765:Obesity; D010298:Parity; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012923:Social Class; D012959:Socioeconomic Factors; D014427:Twins