title: [Study on the karyotype and recurrence risk of malformed newborns].
abstract: OBJECTIVE
  To survey the karyotype and recurrence risk of malformed newborns.
  
  
  METHODS
  Karyotypes of 104 malformed newborns were analyzed using G-banding. All cases were devided into two groups depending on their karyotypes: Group 1 with normal karyotype (n = 51) and group 2 with abnormal (n = 53). Clinical data were compared between malformed groups and control. Women who had the second babies after delivering a malformed (n = 20) were included in the statistics of recurrence risk.
  
  
  RESULTS
  (1) Of 104 cases, 53 had abnormal karyotype (50.96%). They were trisomy 21, trisomy 18, 45X, 1q+ and 5p+ (n = 41, 9, 1, 1, 1, seperately). (2) Within group 2, women's mean delivery age was elder, while premature delivery rate was higher than that of control (P < 0.01, 0.05). In group 1, the proportion of women with abnormal pregnancy history increased as compared with control (P < 0.05). The rate of fetal distress, poly/oligohydramnios and small for gestational age (SGA) of two malformed groups was higher apparently than that of control. The birth weight of two malformed groups declined obviously. (3) Within 20 second babies being born after their malformed siblings, 6 were malformed too. The total recurrence rate was 30%.
  
  
  CONCLUSIONS
  (1) Abnormal karyotype is an important cause of congenital malformations; (2) The age pregnant women abnormal pregnancy history, IUGR and poly/oligohydramnios all may be the high risk factors of congenital malformations; (3) The recurrence rate of malformations rises after the first malformed newborn's birth.
authors.affiliation: Obstetrics and Gynecology Hospital, Shanghai Medical University.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Zhuang
mesh_terms: D002887:Chromosomes, Human, Pair 18; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D011247:Pregnancy; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D014314:Trisomy; D014424:Turner Syndrome / Q000235:genetics