title: [Analysis of clinical features among severe or critical pregnant women in different trimesters with 2009 pandemic H1N1 infection].
abstract: OBJECTIVE
  To explore the disease course and outcomes of severe or critical pregnant women with 2009 pandemic H1N1 (pH1N1) infection in China.
  
  
  METHODS
  A retrospective observational study was conducted for 394 severe or critical pregnant women with pH1N1 influenza admitted into hospital in 27 Chinese provinces from September 1, 2009 to December 31, 2009. Their clinical features in different trimesters were analyzed. The viral infection of pH1N1 was verified by real-time reverse transcription (rRT)-PCR. Severe and critical cases were defined according to the 2009 H1N1 clinical guidelines.
  
  
  RESULTS
  Among them, 374 (94.9%) were infected in the second or third trimester. Fever and cough were the most common symptoms in all trimesters. However, hemoptysis, dyspnea and associated pneumonia were likely to occur in the second or third trimester. The ratio of required mechanical ventilation in the second or third trimester (44.7%, 167/374) was significantly higher than that in the first trimester (3/20). Among 77 mortality cases, 72.7% (56/77) died in the third trimester. Pregnancy was terminated after the onset of pH1N1 symptoms in 52.5%(207/394) pregnant women. And 57.0%(118/207) of them had delivery < 37 weeks and 29.0%(60/207) fetuses deceased.
  
  
  CONCLUSIONS
  A clinician should be on a high alert for pH1N1 infection in pregnant women, particularly in the second or third trimester.
authors.affiliation: Department of Scientific Research, Beijing Hospital, Ministry of Health, Beijing 100730, China.
authors.forename: Peng-jun
authors.initials: PJ
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.forename: Si-nan
authors.initials: SN
authors.lastname: Wu
authors.forename: Yan-ming
authors.initials: YM
authors.lastname: Li
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Li
authors.forename: Li-rong
authors.initials: LR
authors.lastname: Liang
authors.forename: Jian-guo
authors.initials: JG
authors.lastname: Zhu
authors.forename: Shi-gui
authors.initials: SG
authors.lastname: Yang
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: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D011263:Pregnancy Trimester, Third; D012189:Retrospective Studies; D055815:Young Adult