title: Clinical features and risk factors for severe and critical pregnant women with 2009 pandemic H1N1 influenza infection in China.
abstract: BACKGROUND
  2009 pandemic H1N1 (pH1N1) influenza posed an increased risk of severe illness among pregnant women. Data on risk factors associated with death of pregnant women and neonates with pH1N1 infections are limited outside of developed countries.
  
  
  METHODS
  Retrospective observational study in 394 severe or critical pregnant women admitted to a hospital with pH1N1 influenza from Sep. 1, 2009 to Dec. 31, 2009. rRT-PCR testing was used to confirm infection. In-hospital mortality was the primary endpoint of this study. Univariable logistic analysis and multivariate logistic regression analysis were used to investigate the potential factors on admission that might be associated with the maternal and neonatal mortality.
  
  
  RESULTS
  394 pregnant women were included, 286 were infected with pH1N1 in the third trimester. 351 had pneumonia, and 77 died. A PaO(2)/FiO(2) ≤ 200 (odds ratio (OR), 27.16; 95% confidence interval (CI), 2.64-279.70) and higher BMI (i.e. ≥ 30) on admission (OR, 1.26; 95% CI, 1.09 to 1.47) were independent risk factors for maternal death. Of 211 deliveries, 146 neonates survived. Premature delivery (OR, 4.17; 95% CI, 1.19-14.56) was associated neonatal mortality. Among 186 patients who received mechanical ventilation, 83 patients were treated with non-invasive ventilation (NIV) and 38 were successful with NIV. The death rate was lower among patients who initially received NIV than those who were initially intubated (24/83, 28.9% vs 43/87, 49.4%; p = 0.006). Septic shock was an independent risk factor for failure of NIV.
  
  
  CONCLUSIONS
  Severe hypoxemia and higher BMI on admission were associated with adverse outcomes for pregnant women. Preterm delivery was a risk factor for neonatal death among pregnant women with pH1N1 influenza infection. NIV may be useful in selected pregnant women without septic shock.
authors.affiliation: Beijing Chao-Yang Hospital, Beijing Institute of Respiratory Medicine, Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Department of Respiratory Medicine, Capital Medical University, Beijing, China.
authors.forename: Peng-jun
authors.initials: PJ
authors.lastname: Zhang
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Shi-gui
authors.initials: SG
authors.lastname: Yang
authors.forename: Li-rong
authors.initials: LR
authors.lastname: Liang
authors.forename: Li
authors.initials: L
authors.lastname: Gu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xu
authors.forename: Ke
authors.initials: K
authors.lastname: Hu
authors.forename: Hong-yuan
authors.initials: HY
authors.lastname: Zhang
authors.forename: Xi-xin
authors.initials: XX
authors.lastname: Yan
authors.forename: Wen-bao
authors.initials: WB
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Jing-xiao
authors.initials: JX
authors.lastname: Zhang
authors.forename: Lan-juan
authors.initials: LJ
authors.lastname: Li
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D002681:China / Q000453:epidemiology; D016638:Critical Illness; D005260:Female; D005313:Fetal Death / Q000453:epidemiology; D006801:Humans; D000860:Hypoxia / Q000453:epidemiology / Q000401:mortality; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality* / Q000473:pathology / Q000821:virology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000401:mortality* / Q000473:pathology / Q000821:virology; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D055815:Young Adult