title: A multicenter study of fetal chromosomal abnormalities in Chinese women of advanced maternal age.
abstract: OBJECTIVE
  This study aimed to determine the rates of different fetal chromosomal abnormalities among women of advanced maternal age in China and to discuss the possible misdiagnosis risks of newer molecular techniques, for selection of appropriate prenatal screening and diagnostic technologies.
  
  
  METHODS
  Second trimester amniocentesis and fetal karyotype results of 46,258 women were retrospectively reviewed. All women were ≥ 35 years old with singleton pregnancies. The rates of clinically significant chromosomal abnormalities (CSCAs), incidence of chromosomal abnormalities, and correlations with age were determined.
  
  
  RESULTS
  From 2001 to 2010, the proportion of women of advanced maternal age undergoing prenatal diagnosis increased from 20% to 46%. The mean age was 37.4 years (range, 35-46 years). A total of 708 cases of CSCAs, with a rate of 1.53% were found. Trisomy 21 was the most common single chromosome abnormality and accounted for 55.9% of all CSCAs with an incidence of 0.86%. Trisomy 13, trisomy 18, and trisomy 21, the most common chromosome autosomal aneuploidies, accounted for 73.6% of all CSCAs, with a rate of 1.13%. As a group, the most common chromosomal aneuploidies (13/18/21/X/Y) accounted for 93.9% of all abnormalities, with a rate of 1.44%. The incidence of trisomy 21, trisomy 13/18/21 as a group, and 13/18/21/X/Y as a group was significantly greater in women aged 39 years and older (p < 0.001), but was not different between women aged 35 years, 36 years, 37 years, and 38 years.
  
  
  CONCLUSIONS
  These findings may assist in genetic counseling of advanced maternal age pregnant women, and provide a basis for the selection of prenatal screening and diagnostic technologies.
authors.affiliation: Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Prenatal Diagnosis Center of Zhejiang Province, Hangzhou, China.
authors.forename: Yuning
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China; Prenatal Diagnosis Center of Zhejiang Province, Hangzhou, China. Electronic address: lushiminghz@163.com.
authors.forename: Shiming
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Obstetrics and Gynecology, Academy of Medical Science, Chinese Peking Union Medical College, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Xuming
authors.initials: X
authors.lastname: Bian
authors.affiliation: West China Second University Hospital, Sichuan University, Prenatal Diagnosis Center of Sichuan Province, Chengdu, China.
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.affiliation: Genetic Diagnostic Center, the First People's Hospital of Yunnan Province, Kunming, China.
authors.forename: Baosheng
authors.initials: B
authors.lastname: Zhu
authors.affiliation: The Maternal and Child Health Hospital of Hunan Province, Prenatal Diagnosis Center of Hunan Province, Changsha, Hunan, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.affiliation: Center of Prenatal Diagnosis, Nanjing Maternity and Child Health Care Hospital, Nanjing, China.
authors.forename: Zhengfeng
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Center of Prenatal Diagnosis, Maternal and Child Health Hospital of Fujian Province, Fuzhou, China.
authors.forename: Liangpu
authors.initials: L
authors.lastname: Xu
authors.affiliation: Center of Prenatal Diagnosis, Taizhou Hospital, Taizhou, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Yan
authors.affiliation: Center of Prenatal Diagnosis, Shaoxing Maternity and Child Health Care Hospital, Shaoxing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Center of Prenatal Diagnosis, Ningbo Maternity and Child Health Care Hospital, Ningbo, China.
authors.forename: Zhiyang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Center of Prenatal Diagnosis, Wenzhou Central Hospital, Wenzhou, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Tang
authors.affiliation: Center of Prenatal Diagnosis, Huzhou Maternity and Child Health Care Hospital, Huzhou, China.
authors.forename: Guosong
authors.initials: G
authors.lastname: Shen
authors.affiliation: Center of Prenatal Diagnosis, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, China.
authors.forename: Zhengyou
authors.initials: Z
authors.lastname: Miao
mesh_terms: D000328:Adult; D000649:Amniocentesis; D002681:China; D002869:Chromosome Aberrations / Q000706:statistics & numerical data*; D025063:Chromosome Disorders / Q000453:epidemiology; D002882:Chromosomes, Human, Pair 13; D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D007621:Karyotyping; D008423:Maternal Age; D008875:Middle Aged; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D012189:Retrospective Studies; D012729:Sex Chromosome Aberrations; D014314:Trisomy; D000073839:Trisomy 13 Syndrome; D000073842:Trisomy 18 Syndrome
keywords: advanced maternal age; amniotic fluid; clinically significant chromosome abnormalities; genetic counseling; prenatal diagnosis