Outcomes for pregnant women infected with the influenza A (H1N1) virus during the 2009 pandemic in Porto Alegre, Brazil.

Objective: To study the epidemiologic characteristics and underlying conditions that place pregnant women infected with H1N1 virus at increased risk for being admitted to the intensive care unit (ICU).

Methods: In this cross-sectional study conducted in Porto Alegre, Brazil, with 57 pregnant women hospitalized with the H1N1 influenza during the 2009 pandemic, we collected epidemiologic characteristics and assessed the rates of ICU admission according to pregnancy duration and the presence or absence of comorbidities.

Results: The median (range) of maternal age was 26 years (15-41 years), the pregnancy duration at the time of infection was 29 weeks (8-41 weeks), and the birth weight was 3180 g (740-3900 g). Five patients (8.8%) were in the first, 22 (38.6%) in the second, and 30 (52.6%) in the third trimester, and (22.8%) had comorbidities. Antiviral drugs were administered to all, and 46 (80.7%) patients received an early treatment. There were no maternal, fetal, or neonatal deaths. Eight patients (14%) required ICU admission and 15 (50%) of the patients who gave birth during their hospitalization underwent a cesarean delivery. The risk of being treated at the ICU did not increase for patients with comorbidities (P=0.22) or an advanced pregnancy (P=0.31). The study revealed a relationship between early initiation of an antiviral treatment and a lower mortality rate.

Conclusion: Neither an advanced pregnancy nor comorbidities increased the risk of being admitted to the ICU but, compared with the results of other studies, a prompt treatment lowered mortality.