title: Correlation of angiotensin converting enzyme activity and the genotypes of the I/D polymorphism in the ACE gene with preterm birth and birth weight.
abstract: OBJECTIVE
  Preterm birth remains one of the most challenging areas in obstetrics. The pathogenesis of preterm labor is multifactorial and research on preterm birth has focused principally on infection and inflammatory markers. Recently the focus has turned to potential genetic factors influencing preterm birth. Uteroplacental insufficiency and thrombotic vasculopathy are considered part of the pathogenesis of preterm labor. Investigating the gene expression in the maternal/fetal interface seems of importance to expand our knowledge of the pathophysiology of preterm birth. The renin-angiotensin system (RAS) appears to play an important role in fetal/placental development and uteroplacental circulation. Hence, the aim of this study was to investigate angiotensin converting enzyme (ACE) activity and I/D polymorphisms in the ACE gene in mothers and infants with appropriately grown infants in relation to preterm birth and infant birth weight.
  
  
  METHODS
  We conducted a cross-sectional study of 113 term pregnancies (> or =37 weeks) and 18 preterm pregnancies (<37 weeks). Umbilical cord bloods (venous and arterial) were obtained from the placenta immediately after delivery for serum ACE activity, ACE genotype analysis of the I/D polymorphism and the acid-base status. Maternal venous samples were obtained just after delivery for analysis of ACE activity and ACE genotype.
  
  
  RESULTS
  The distribution of the maternal ACE genotypes was similar for preterm and term births as was maternal ACE activity. Preterm infants were more likely to be of the DD genotype than term infants (7/18 (39%) vs. 11/83 (13%), p=0.02) (adjusted p=0.04). There was no correlation between ACE activity and birth weight (r(2) 0.00, p=0.82).
  
  
  CONCLUSIONS
  These findings suggest that the ACE genotype of the infant may influence the risk of preterm birth among appropriately grown fetuses.
authors.affiliation: Division of Maternal and Child Health Sciences, University of Dundee, United Kingdom. r.uma@dundee.ac.uk
authors.forename: Ramalingam
authors.initials: R
authors.lastname: Uma
authors.forename: J Stewart
authors.initials: JS
authors.lastname: Forsyth
authors.forename: Allan D
authors.initials: AD
authors.lastname: Struthers
authors.forename: Callum G
authors.initials: CG
authors.lastname: Fraser
authors.forename: Valerie
authors.initials: V
authors.lastname: Godfrey
authors.forename: Deirdre J
authors.initials: DJ
authors.lastname: Murphy