title: Airflow limitations in pregnant women suspected of sleep-disordered breathing.
abstract: OBJECTIVE
  Pregnancy physiology may predispose women to the development of airflow limitations during sleep. The goal of this study was to evaluate whether pregnant women suspected of sleep-disordered breathing (SDB) are more likely to have airflow limitations compared to non-pregnant controls.
  
  
  METHODS
  We recruited pregnant women referred for polysomnography for a diagnosis of SDB. Non-pregnant female controls matched for age, body mass index (BMI), and apnoea-hypopnoea index (AHI) were identified from a database. We examined airflow tracings for changes in amplitude and shape. We classified airflow limitation by (a) amplitude criteria defined as decreased airflow of > or =10 s without desaturation or arousal (FL 10), or decreased airflow of any duration combined with either 1-2% desaturation or arousal, (FL 1-2%); and (b) shape criteria defined as the presence of flattening or oscillations of the inspiratory flow curve.
  
  
  RESULTS
  We identified 25 case-control pairs. Mean BMI was 44.0±6.9 in cases and 44.1±7.3 in controls. Using shape criteria, pregnant women had significantly more flow-limited breaths throughout total sleep time (32.4±35.8 vs. 9.4±17.9, p<0.0001) and in each stage of sleep (p<0.0001) than non-pregnant controls. In a subgroup analysis, pregnant women without a diagnosis of obstructive sleep apnoea (OSA) who had an AHI <5 had similar findings (p<0.0001). There was no difference in airflow limitation by amplitude criteria between pregnant women and controls (p=0.22).
  
  
  CONCLUSIONS
  Pregnant women suspected of OSA have more frequent shape-defined airflow limitations than non-pregnant controls, even when they do not meet polysomnographic OSA criteria.
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI, USA; Department of Medicine, The Miriam Hospital, Providence, RI, USA; Department of Medicine, Rhode Island Hospital, Providence, RI, USA. Electronic address: Ghada_Bourjeily@Brown.edu.
authors.forename: Ghada
authors.initials: G
authors.lastname: Bourjeily
authors.affiliation: Mount Sinai Hospital Pulmonary Fellowship Program, New York, NY, USA.
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Fung
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI, USA; Department of Medicine, Rhode Island Hospital, Providence, RI, USA.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Sharkey
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI, USA.
authors.forename: Palak
authors.initials: P
authors.lastname: Walia
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Kao
authors.affiliation: Department of Medicine, Rhode Island Hospital, Providence, RI, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Moore
authors.affiliation: Department of Medicine, The Miriam Hospital, Providence, RI, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Martin
authors.affiliation: Women and Infants Hospital of Rhode Island, Division of Research, Providence, RI, USA.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Raker
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI, USA; Department of Medicine, Rhode Island Hospital, Providence, RI, USA.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Millman
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017286:Polysomnography; D011247:Pregnancy; D011248:Pregnancy Complications / Q000503:physiopathology*; D012143:Respiratory Physiological Phenomena; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology
keywords: Airflow limitation; Obesity; Obstructive sleep apnoea; Preeclampsia; Pregnancy; Sleep-disordered breathing