title: Identification of feto-maternal haemorrhage around labour using flow cytometry immunophenotyping.
abstract: OBJECTIVE
  To determine the normal range of feto-maternal haemorrhage (FMH) due to labour, and to investigate if the type of delivery might influence the volume of FMH.
  
  
  METHODS
  In a prospective cohort trial setting we studied 346 women in their 3rd trimester of gestation. Women were classified according to the type of delivery: vaginal, instrumental and caesarean section. Fetal erythrocytes in maternal blood were measured by flow cytometry immunophenotyping using a fluorochrome-conjugated monoclonal antibody against fetal haemoglobin. For each woman, two blood samples were studied; one pre-labour and one post-labour. The difference between FMH values obtained post- and pre-delivery was established as FMH due to delivery.
  
  
  RESULTS
  FMH due to labour ranged between <0.01 and 25.19 ml, being <1.15 ml in 96.13% of cases. This value was established as the upper limit of normal FMH due to delivery. No statistical significance was found between the volume of FMH and type of delivery. Analyzing distributions of groups, most data followed a normal distribution, apart from some patients who had higher volume of FMH. Among these patients caesarean sections showed a higher FMH volume, with statistically significant differences between vaginal deliveries and caesarean sections (p=0.001), and between instrumental deliveries and caesarean sections (p=0.008).
  
  
  CONCLUSIONS
  FMH due to labour is small. The route of delivery could not be established as a risk factor for FMH but caesarean section increases the risk of suffering a higher amount of transplacental bleeding.
authors.affiliation: Dept Gynecology and Obstetrics, Hospital Quirón, Pozuelo de Alcorcón, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Uriel
authors.forename: D
authors.initials: D
authors.lastname: Subirá
authors.forename: J
authors.initials: J
authors.lastname: Plaza
authors.forename: S
authors.initials: S
authors.lastname: Castañón
authors.forename: M
authors.initials: M
authors.lastname: Cañamares
authors.forename: J Díaz
authors.initials: JD
authors.lastname: Recasens
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000009:adverse effects; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000009:adverse effects; D005260:Female; D005331:Fetomaternal Transfusion / Q000175:diagnosis* / Q000209:etiology; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007743:Labor, Obstetric / Q000097:blood*; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors