title: Changes in distribution of gestational age and birth weight among firstborn infants of Cardiff residents.
abstract: We studied data on firstborn singleton infants born to primiparous Cardiff residents during the decade 1965-1974. Both mean birth weight and gestational age at delivery fell appreciably during 1965-74. Changes in maternal age, height, smoking habits, or history of abortion did not explain these findings. The increased proportion of infants weighing less than 2500 g may be explained by the overall reduction in gestational age at delivery, which, in turn, may have resulted from increased use of elective delivery during the second quinquennium.
mesh_terms: D000022:Abortion, Spontaneous; D000367:Age Factors; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced; D011247:Pregnancy; D012907:Smoking; D014852:Wales