Influenza in Pregnant Women: Experience During the Pandemic Influenza A (H1N1)

Background: As already observed in previous pandemics, during the pandemic influenza A H1N1 there was a higher risk of morbidity and mortality in pregnant women. In Brazil mortality rate in pregnants with H1N1 is 10.6% and 9.1% in the state of Sao Paulo.

Objective: Describe the epidemiological characteristics and clinical course of pregnant women admitted with flu-like illness and confirmed cases of influenza A H1N1.

Methods: Retrospective and descriptive study that examined the epidemiological and clinical characteristics of pregnants admitted with flu-like illness in two private maternity hospitals in São Paulo, from July 01 to August 20, 2009. The criteria to define cases of influenza A H1N1 were based on definitions of the Brazilian Ministry of Health and the diagnosis was confirmed by real time PCR for A H1N1. All patients were followed by a clinical, infectious disease specialist and obstetrician during the period of hospitalization.

Results: During the study period 826 pregnant women sought emergency treatment with flu-like illness. Of these 31 (3.75%) were hospitalized for monitoring clinical and obstetrical conditions.  Age range was 20 to 42 years (mean 28y). In relation to gestational age  6.5%  were in the first trimester, 19.5% in the second and 74% in third. Of the 31 cases, 19 (61.2%) had confirmed result for influenza A H1N1 and four (21%) of them a history of asthma. There was no statistical difference comparing the symptoms reported by women with H1N1 positive and negative results. Only two confirmed H1N1 patient required hospitalization in the intensive unit and none had need of mechanical ventilation. Treatment with oseltamivir was indicated in 28/31 patients. No pregnant women developed obstetric complications or death in both groups. Some characteristics of pregnants are described in the following table.

	P.  value	Evolution  of symptoms until hospitalization	Hospital stay	Resolution of pregnancy	Antibiotic therapy	Received Oseltamivir	P.  value
H1N1 +  (19)	0.052	≤ 48hs 16 (84,2%)	>48hs  13 (68,5%) < 48hs  6 (31,5%)	On admission   2 (11,7%)    After discharge 6 (35,2%) Not availeble     11	yes 7(36,8%) no 12(63,2%)	Total   19 (100%) ≥48hs  3 (15,7%)         ≤48hs  16 (84,2%)	0.022
H1N1 – (12)		≤ 48hs   6 (50%)	>48hs  7 (58,3%) < 48hs 5 (41,4%)	On admission   1 (8,3%)             After discharge 1 (8,3%) Not availeble     10	yes 4 (33,4%) no  8 (66,6%)	Total   10 (83,3%)        ≥48hs   4(40%)      ≤48h     6(60%)

Conclusions: The mortality rate from our hospital in H1N1 pregnant women was lower than the one reported in Brazilians population. These results could be related to the early  prescription of specific antiviral therapy and rapid access to medical care for our pregnant women population