title: Pregnancy outcomes in women with mechanical prosthetic heart valves: a prospective descriptive population based study using the United Kingdom Obstetric Surveillance System (UKOSS) data collection system.
abstract: OBJECTIVE
  To describe the incidence of mechanical prosthetic heart valves (MPHV) in pregnancy in the UK; rates of maternal and fetal complications in this group of women, and whether these vary with the anticoagulation used during pregnancy.
  
  
  METHODS
  Prospective descriptive population-based study.
  
  
  METHODS
  All consultant-led maternity units in the UK.
  
  
  METHODS
  All women with an MPHV who were pregnant between 1 February 2013 and 31 January 2015.
  
  
  METHODS
  Collection and analysis of anonymous data relating to pregnancy management and outcome, using the UKOSS notification and data collection system.
  
  
  METHODS
  Maternal death, serious maternal morbidity, poor fetal outcome.
  
  
  RESULTS
  Data were obtained for 58 women giving an estimated incidence of 3.7 (95% CI 2.7-4.7) per 100 000 maternities. There were five maternal deaths (9%); a further 24 (41%) suffered serious maternal morbidity. There was a poor fetal outcome from 26 (47%) pregnancies. Only 16 (28%) women had a good maternal and good fetal outcome. Low-molecular-weight heparin (LMWH) was used throughout pregnancy by 71% of women. Of these, 83% required rapid dose escalation in the first trimester. Monitoring regimens lacked consistency.
  
  
  CONCLUSIONS
  This study has estimated the incidence of MPHV in pregnant women in the UK. It includes the largest cohort managed with LMWH throughout pregnancy reported to date. It demonstrates a high rate of maternal death, and serious maternal and fetal morbidity. Women with MPHVs, and their clinicians need to appreciate the significant maternal and fetal risks involved in pregnancy. Care should be concentrated in specialist centres.
  
  
  CONCLUSIONS
  High rates of poor maternal and fetal outcomes in pregnant women with mechanical prosthetic heart valves.
authors.affiliation: Obstetric Directorate, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.|Institute of Human Development, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
authors.forename: S
authors.initials: S
authors.lastname: Vause
authors.affiliation: Manchester Heart Centre, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.|Institute of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
authors.forename: B
authors.initials: B
authors.lastname: Clarke
authors.affiliation: Obstetric Directorate, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.|Institute of Human Development, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
authors.forename: C L
authors.initials: CL
authors.lastname: Tower
authors.affiliation: Department of Haematology, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.|Institute of Cancer Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
authors.forename: Crm
authors.initials: C
authors.lastname: Hay
authors.affiliation: National Perinatal Epidemiology Unit, University of Oxford, Oxford, UK.
authors.forename: M
authors.initials: M
authors.lastname: Knight
mesh_terms: D000293:Adolescent; D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D006350:Heart Valve Prosthesis; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use; D006801:Humans; D015994:Incidence; D008428:Maternal Mortality; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D011256:Pregnancy Outcome; D011295:Prenatal Care / Q000379:methods; D011379:Prognosis; D011446:Prospective Studies; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight
keywords: Anticoagulation; fetal outcome; maternal outcome; mechanical prosthetic heart valve; pregnancy