title: Reproductive outcomes in women with congenital uterine anomalies: a systematic review.
abstract: OBJECTIVE
  Congenital uterine anomalies are common but their effect on reproductive outcome is unclear. We conducted a systematic review to evaluate the association between different types of congenital uterine anomaly and various reproductive outcomes.
  
  
  METHODS
  Searches were performed using MEDLINE, EMBASE, the Cochrane Library and Web of Science. The Newcastle-Ottawa Quality Assessment Scale was used for quality assessment. Uterine defects were grouped into arcuate uteri, canalization defects (septate and subseptate uteri) and unification defects (unicornuate, bicornuate and didelphys uteri). Pooled risk ratios (RR) with 95% confidence intervals (CI) were computed using random effects models.
  
  
  RESULTS
  We identified nine studies comprising 3805 women. Meta-analysis showed that arcuate uteri were associated with increased rates of second-trimester miscarriage (RR, 2.39; 95% CI, 1.33-4.27, P = 0.003) and fetal malpresentation at delivery (RR, 2.53; 95% CI, 1.54-4.18; P < 0.001). Canalization defects were associated with reduced clinical pregnancy rates (RR, 0.86; 95% CI, 0.77-0.96; P = 0.009) and increased rates of first-trimester miscarriage (RR, 2.89; 95% CI; 2.02-4.14; P < 0.001), preterm birth (RR, 2.14; 95% CI, 1.48-3.11; P < 0.001) and fetal malpresentation (RR, 6.24; 95% CI, 4.05-9.62; P < 0.001). Unification defects were associated with increased rates of preterm birth (RR, 2.97; 95% CI, 2.08-4.23; P < 0.001) and fetal malpresentation (RR, 3.87; 95% CI, 2.42-6.18; P < 0.001).
  
  
  CONCLUSIONS
  Canalization defects reduce fertility and increase rates of miscarriage and preterm delivery. None of the unification defects reduces fertility but some are associated with miscarriage and preterm delivery. Arcuate uteri are specifically associated with second-trimester miscarriage. All uterine anomalies increase the chance of fetal malpresentation at delivery.
authors.affiliation: Department of Obstetrics and Gynaecology, Nottingham University Hospitals NHS Trust, Derby Road, Nottingham, UK. yeeyin@gmail.com
authors.forename: Y Y
authors.initials: YY
authors.lastname: Chan
authors.forename: K
authors.initials: K
authors.lastname: Jayaprakasan
authors.forename: A
authors.initials: A
authors.lastname: Tan
authors.forename: J G
authors.initials: JG
authors.lastname: Thornton
authors.forename: A
authors.initials: A
authors.lastname: Coomarasamy
authors.forename: N J
authors.initials: NJ
authors.lastname: Raine-Fenning
mesh_terms: D000022:Abortion, Spontaneous; D005260:Female; D005298:Fertility; D006801:Humans; D007746:Labor Presentation; D015201:Meta-Analysis as Topic; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth; D012307:Risk Factors; D014591:Uterine Diseases / Q000150:complications / Q000151:congenital*; D014599:Uterus / Q000002:abnormalities*