title: Maternal obesity and its effect on placental cell turnover.
abstract: BACKGROUND
  Maternal obesity is a frequent obstetric risk factor, linked with short- and long-term consequences for mother and child, including foetal overgrowth, growth restriction and stillbirth. The mechanisms underlying these pathologies remain unknown but likely involve the placenta.
  
  
  OBJECTIVE
  To study placental cell turnover in relation to maternal body mass index (BMI).
  
  
  METHODS
  Term placental villous tissue was randomly sampled from 24 pregnancies, with a range of maternal BMI of 19.5-49.6. Immunohistochemistry was performed for human chorionic gonadotropin, Ki67 and M30 and image analysis used to calculate syncytiotrophoblast area and proliferative and apoptotic indices. Results were compared categorically between women of BMI 18.5-24.9 (normal), BMI 30.0-39.9 (obese classes 1 and 2) and BMI 40+ (obese class 3) and continuously against BMI; p < 0.05 by the Kruskal-Wallis test or linear regression was considered statistically significant.
  
  
  RESULTS
  Increased maternal BMI was associated with categorical (normal versus obese class 3 and obese classes 1 and 2 versus obese class 3, both p < 0.05) and continuous (r(2) = 0.24, p = 0.016) reductions in the proliferative index and a continuous reduction (r(2) = 0.17, p = 0.047) in the apoptotic index.
  
  
  CONCLUSIONS
  Maternal obesity is associated with a dose-dependent reduction in placental villous proliferation and apoptosis which may increase susceptibility to adverse pregnancy outcomes.
authors.affiliation: Maternal and Fetal Health Research Centre, Institute of Human Development, Manchester Academic Health Science Centre, St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, University of Manchester, Manchester, UK. Lucy.higgins@manchester.ac.uk
authors.forename: Lucy
authors.initials: L
authors.lastname: Higgins
authors.forename: Tracey A
authors.initials: TA
authors.lastname: Mills
authors.forename: Susan L
authors.initials: SL
authors.lastname: Greenwood
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Cowley
authors.forename: Colin P
authors.initials: CP
authors.lastname: Sibley
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Jones
mesh_terms: D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D009765:Obesity / Q000473:pathology* / Q000503:physiopathology; D010920:Placenta / Q000473:pathology* / Q000503:physiopathology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult