title: Endoreduplication in cervical trophoblast cells from normal pregnancies.
abstract: OBJECTIVE
  Fetal cells represented by extravillous trophoblasts (EVT) obtained from the cervix by a minimally invasive procedure are important for prenatal diagnosis in early pregnancies. Endoreduplication is a duplication of chromosomes without mitosis, leading to polyploidy that might represent increased cellular metabolic activity. In this study, we estimated the normal prevalence of polyploid trophoblasts exfoliated to the cervix between 5 and 13 weeks of gestation.
  
  
  METHODS
  Cervical samples were obtained by cytobrush, between 5 and 13 weeks of gestation from 36 randomly selected, singleton pregnancies. FISH was done with X, Y and two 21 probes.
  
  
  RESULTS
  We diagnosed 21 pregnancies with female and 15 pregnancies with male fetal karyotypes. A mean of 15.2 (0.02%) tetraploid cells were found in pregnancies with a female fetus and a mean of 2.0 (0.003%) tetraploid cells were found in pregnancies with a male fetus. The tetraploid cells (endoreduplicated trophoblasts) were two to three times larger than the normal cells usually seen in the cervix.
  
  
  CONCLUSIONS
  Extravillus trophoblasts tend to form endoreduplication to the ploidy level of 4c-8c of DNA. Those cells may represent a typical phenomenon in the growing placenta. Extravillus trophoblasts from female fetuses tend to form higher rates of endoreduplication.
authors.affiliation: Department of Obstetrics and Gynecology , Meir Medical Center, Kfar Saba, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Biron-Shental
authors.forename: Moshe D
authors.initials: MD
authors.lastname: Fejgin
authors.forename: Stavros
authors.initials: S
authors.lastname: Sifakis
authors.forename: Meytal
authors.initials: M
authors.lastname: Liberman
authors.forename: Aris
authors.initials: A
authors.lastname: Antsaklis
authors.forename: Aliza
authors.initials: A
authors.lastname: Amiel
mesh_terms: D002584:Cervix Uteri / Q000166:cytology / Q000378:metabolism*; D015193:Chorionic Villi Sampling; D062951:Endoreduplication / Q000502:physiology*; D005189:False Positive Reactions; D005260:Female; D006262:Health; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping / Q000379:methods; D008297:Male; D011123:Polyploidy; D011247:Pregnancy / Q000235:genetics* / Q000378:metabolism; D011261:Pregnancy Trimester, First / Q000235:genetics / Q000378:metabolism; D011296:Prenatal Diagnosis / Q000379:methods; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D054928:Validation Studies as Topic