title: The use of twinning rates as a reproductive health monitor in England and Wales 1988-1996.
authors.forename: W H
authors.initials: WH
authors.lastname: James
mesh_terms: D000328:Adult; D000367:Age Factors; D004739:England; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011786:Quality Control; D012099:Reproductive Techniques; D014427:Twins; D014852:Wales