Kiely J L, Kiely M
Child Health Statistics Center, Institute for Health Policy & Health Services Research, University of Cincinnati, OH, USA.
Twin Res. 2001 Jun;4(3):131-3. doi: 10.1375/1369052012335.
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.
美国多胞胎出生率持续惊人地上升。我们分析了美国国家卫生统计中心的出生记录。计算了1971 - 1977年以及1990年至1998年每年的双胞胎、三胞胎、四胞胎和五胞胎及以上的出生率。还按母亲的教育程度和年龄类别计算了三胞胎出生率。双胞胎出生率从1971 - 1977年的1.8%上升到1998年的2.8%。1971 - 1977年至1998年间，三胞胎出生率增长了5.9倍，四胞胎增长了11.9倍，五胞胎及以上增长了5.3倍。受过大学教育的女性和30岁及以上女性所生三胞胎的出生率增长更为显著。在45岁及以上的女性中，1998年的三胞胎出生率比1971 - 1977年高出约50倍。在1998年，这组年龄较大的女性（≥45岁）的多胞胎出生率最高。
