title: Maternal and neonatal outcomes in women undergoing bariatric surgery: a systematic review and meta-analysis.
abstract: BACKGROUND
  Obese women are at increased risk for many pregnancy complications, and bariatric surgery (BS) before pregnancy has shown to improve some of these.
  
  
  OBJECTIVE
  To review the current literature and quantitatively assess the obstetric and neonatal outcomes in pregnant women who have undergone BS.
  
  
  METHODS
  MEDLINE, EMBASE and Cochrane databases were searched using relevant keywords to identify studies that reported on pregnancy outcomes after BS.
  
  
  METHODS
  Pregnancy outcome in firstly, women after BS compared to obese or BMI-matched women with no BS and secondly, women after BS compared to the same or different women before BS. Only observational studies were included.
  
  
  METHODS
  Two investigators independently collected data on study characteristics and outcome measures of interest. These were analysed using the random effects model. Heterogeneity was assessed and sensitivity analysis was performed to account for publication bias.
  
  
  RESULTS
  The entry criteria were fulfilled by 17 non-randomised cohort or case-control studies, including seven with high methodological quality scores. In the BS group, compared to controls, there was a lower incidence of preeclampsia (OR 0.45, 95% CI 0.25-0.80; P=0.007), GDM (OR 0.47, 95% CI 0.40-0.56; P<0.001) and large neonates (OR 0.46, 95% CI 0.34-0.62; P<0.001) and a higher incidence of small neonates (OR 1.93, 95% CI 1.52-2.44; P<0.001), preterm birth (OR 1.31, 95% CI 1.08-1.58; P=0.006), admission for neonatal intensive care (OR 1.33, 95% CI 1.02-1.72; P=0.03) and maternal anaemia (OR 3.41, 95% CI 1.56-7.44, P=0.002).
  
  
  CONCLUSIONS
  BS as a whole improves some pregnancy outcomes. Laparoscopic adjustable gastric banding does not appear to increase the rate of small neonates that was seen with other BS procedures. Obese women of childbearing age undergoing BS need to be aware of these outcomes.
authors.affiliation: Department of Obstetrics and Gynaecology, Whittington Hospital, London, UK. Electronic address: ngalazis@gmail.com.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Galazis
authors.affiliation: School of Clinical Sciences, University of Nottingham, UK.
authors.forename: Nikolina
authors.initials: N
authors.lastname: Docheva
authors.affiliation: Department of General Surgery, Ealing Hospital, London, UK.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Simillis
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College, London, UK.
authors.forename: Kypros H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000740:Anemia / Q000453:epidemiology; D050110:Bariatric Surgery; D002585:Cesarean Section; D016640:Diabetes, Gestational / Q000453:epidemiology; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology; D006801:Humans; D007236:Infant, Small for Gestational Age; D015931:Intensive Care, Neonatal; D009765:Obesity / Q000601:surgery*; D011225:Pre-Eclampsia / Q000453:epidemiology; D016742:Preconception Care; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth / Q000453:epidemiology
keywords: Bariatric surgery; Birth weight; Gestational diabetes; Preeclampsia; Pregnancy