A multicenter cohort study of pregnancy outcomes among women with laboratory-confirmed H1N1 influenza.
OBJECTIVE
To evaluate associations between laboratory-confirmed 2009 H1N1 influenza infection and obstetric and neonatal outcomes.


METHODS
A multicenter cohort study was performed comparing laboratory-confirmed cases of 2009 H1N1 infection during pregnancy (N=142) with matched controls (N=710). Subanalysis was also performed comparing severely infected (hospitalized) women with controls.


RESULTS
No outcome differences were noted in comparing all women with H1N1 with controls. Women with severe infection had a higher incidence of delivering a small for gestational age (SGA) infant: 18.8% (6/32) versus 7.4% (52/707), adjusted odds ratio 2.35 (95% confidence interval 1.03, 5.36, P=0.02). Mean birth weight was 3013.0 g among severely infected women and 3223.3 g in controls (P=0.08), and incidence of preterm delivery was 25.0% (8/32) and 11.6% (82/710) (P=0.08), respectively.


CONCLUSIONS
Pregnant women with mild clinical illness secondary to 2009 H1N1 were not at a greater risk of adverse pregnancy outcomes. However, severely infected women were more likely to deliver SGA infants.
Department of Obstetrics, Gynecology and Reproductive Sciences, Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
A
A
Naresh
B M
BM
Fisher
K K
KK
Hoppe
J
J
Catov
J
J
Xu
J
J
Hart
A M
AM
Lynch
R
R
Gibbs
D
D
Eschenbach
M
M
Gravett
R H
RH
Beigi
D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications*; D011247:Pregnancy; D011248:Pregnancy Complications; D011251:Pregnancy Complications, Infectious; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology