Objective: To investigate the clinical characteristics of severe influenza A (H1N1) in pregnant women.
Methods: Sixteen patients with severe pneumonia caused by influenza A (H1N1) were included in this study from November 26 to December 20, 2009.
Results: All of the sixteen patients were young women, and 15 of them were pregnant. Leukopenia was observed in 2 cases of the 16 patients, and lymphopenia in 14 cases. Data on the ratio of CD(4) cells to CD(8) cells were available for 12 patients, and 7 cases of whom had an abnormal CD(4)/CD(8) ratio (< 1.4). Eleven of the 15 patients had increased serum lactate dehydrogenase levels, which were above 245 U/L. Three patients had elevated creatine kinase levels at admission. Five cases of the 16 patients had decreased serum potassium levels, which were below 3.5 mmol/L. Four patients had C(4) levels greater than 36 mg per deciliter, and 4 cases had C(3) less than 75 mg per deciliter. All 16 patients had radiologically confirmed pneumonia with bilateral patchy alveolar opacities, affecting 3 or 4 lung quadrants. Findings on chest radiographs were consistent with acute respiratory distress syndrome in all patients requiring mechanical ventilation. A small amount of pleural effusion was found in 4 cases, and pericardial effusion was found in 1 of them. Respiratory distress requiring intubation and mechanical ventilation developed in 9 pregnant patients within the first 24 hours after admission, and 2 of them in the third trimester died, while 7 patients for whom pregnancy was timely terminated recovered.
Conclusions: Pregnant women with 2009 pandemic influenza A (H1N1) appear to have an increased risk of severe disease characterized by severe pneumonia and respiratory failure. Early anti-viral therapy, early termination of pregnancy, and timely mechanical ventilation may bring clinical benefits to pregnant patients.