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Multicenter Study
. 2010 Mar 18:340:c1279.
doi: 10.1136/bmj.c1279.

Critical illness due to 2009 A/H1N1 influenza in pregnant and postpartum women: population based cohort study

ANZIC Influenza Investigators and Australasian Maternity Outcomes Surveillance System
Multicenter Study

Critical illness due to 2009 A/H1N1 influenza in pregnant and postpartum women: population based cohort study

ANZIC Influenza Investigators and Australasian Maternity Outcomes Surveillance System. BMJ. .

Abstract

Objective: To describe the epidemiology of 2009 A/H1N1 influenza in critically ill pregnant women.

Design: Population based cohort study.

Setting: All intensive care units in Australia and New Zealand.

Participants: All women with 2009 H1N1 influenza who were pregnant or recently post partum and admitted to an intensive care unit in Australia or New Zealand between 1 June and 31 August 2009.

Main outcome measures: Maternal and neonatal mortality and morbidity.

Results: 64 pregnant or postpartum women admitted to an intensive care unit had confirmed 2009 H1N1 influenza. Compared with non-pregnant women of childbearing age, pregnant or postpartum women with 2009 H1N1 influenza were at increased risk of admission to an intensive care unit (relative risk 7.4, 95% confidence interval 5.5 to 10.0). This risk was 13-fold greater (13.2, 9.6 to 18.3) for women at 20 or more weeks' gestation. At the time of admission to an intensive care unit, 22 women (34%) were post partum and two had miscarried. 14 women (22%) gave birth during their stay in intensive care and 26 (41%) were discharged from an intensive care unit with ongoing pregnancy. All subsequently delivered. 44 women (69%) were mechanically ventilated. Of these, nine (14%) were treated with extracorporeal membrane oxygenation. Seven women (11%) died. Of 60 births after 20 weeks' gestation, four were stillbirths and three were infant deaths. 22 (39%) of the liveborn babies were preterm and 32 (57%) were admitted to a neonatal intensive care unit. Of 20 babies tested, two were positive for the 2009 H1N1 virus.

Conclusions: Pregnancy is a risk factor for critical illness related to 2009 H1N1 influenza, which causes maternal and neonatal morbidity and mortality.

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Conflict of interest statement

Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare that (1) no authors have support from any company for the submitted work; (2) no authors have any relationships with any companies that might have an interest in the submitted work in the previous 3 years; (3) their spouses, partners, or children have no financial relationships that may be relevant to the submitted work; and (4) no authors have non-financial interests that may be relevant to the submitted work.

Figures

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Fig 1 Outcomes after admission to intensive care unit
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Fig 2 Gestation at onset of influenza symptoms in women, according to pregnancy status
See this image and copyright information in PMC

Comment in

References

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