title: [Multiple pregnancy--a significant complication of in vitro fertilization protocols].
abstract: OBJECTIVE
  To evaluate the history of pregnancies after IVF-ET, to define multiple pregnancy risk factors.
  
  
  METHODS
  A retrospective analysis of the period of 1992-2000.
  
  
  METHODS
  Department of Gynecology and Obstetrics, University Hospital, Palacký University, Olomouc.
  
  
  METHODS
  343 pregnancies were evaluated, divided into 4 groups according to the patients' ages: < or = 29 yrs. (n = 150), 30-34 yrs. (n = 122), 35-39 yrs. (n = 66), > or = 40 yrs. (n = 5). The number of transferred embryos and frequency of pregnancies in relation to the patient' ages were compared as well as the multiple pregnancy and spontaneous abortion rates. The dependence of preterm labour rate, foetus weight and the incidence of operative delivery on the frequency of pregnancies were evaluated (n = 276). The data were analysed using the chi 2 and Sheffe tests.
  
  
  RESULTS
  Three or four transferred embryos markedly increase the number of multiple pregnancies (P < 0.01). No relation to the patient's ages was found. An increased incidence of operative deliveries (P < 0.01) as well as preterm deliveries (P < 0.05) in multiple pregnancies was found.
  
  
  CONCLUSIONS
  The number of transferred embryos is the most important risk factor for multiple pregnancy development. It is recommended to decrease the number of transferred embryos to two or one per ET.
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D001724:Birth Weight; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012189:Retrospective Studies