title: Epidemiological trends in multiple births in the United States, 1971-1998.
abstract: The astounding rise in multiple births in the United States continues. We analyzed live birth files from the U.S. National Center for Health Statistics. Twin, triplet, quadruplet, and quintuplet+ rates were calculated for the period 1971-1977 and for each year between 1990 and 1998. Triplet rates were also computed within categories of mother's education and age. The twin rate increased from 1.8% in 1971-77 to 2.8% in 1998. The rate of triplets increased 5.9-fold, quadruplets 11.9-fold, and quintuplets+ 5.3-fold between 1971-77 and 1998. Increases in triplet rates were much more marked among births to university-educated women and women 30 years and older. Among women 45 years and older, the triplet rate was approximately fifty times higher in 1998 than in 1971-77. This group of older women (> or = 45 years) had the highest multiple birth rate in 1998.
authors.affiliation: Child Health Statistics Center, Institute for Health Policy & Health Services Research, University of Cincinnati, OH, USA. John.Kiely@UC.Edu
authors.forename: J L
authors.initials: JL
authors.lastname: Kiely
authors.forename: M
authors.initials: M
authors.lastname: Kiely
mesh_terms: D000328:Adult; D017677:Age Distribution; D001723:Birth Rate / Q000639:trends*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D009099:Multiple Birth Offspring / Q000706:statistics & numerical data*; D009309:National Center for Health Statistics, U.S.; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D012042:Registries; D012959:Socioeconomic Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology