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Table 5 Clinical manifestations and outcomes in pregnant admissions by influenza infection status

From: Epidemiology of influenza in pregnant women hospitalized with respiratory illness in Moscow, 2012/2013–2015/2016: a hospital-based active surveillance study

  Influenza positive Influenza negative Odds ratio (95% CI) a  
Clinical manifestation/outcome N = 825 N = 923 P-value
Signs/symptoms, n (%)
 Fever 801 (97.1) 781 (84.6) 6.07 (3.89–9.46) <  0.001
 Headache 445 (53.9) 489 (53.0) 1.04 (0.86–1.25) 0.688
 Malaise 497 (60.2) 550 (59.6) 1.03 (0.85–1.24) 0.781
 Myalgia 354 (42.9) 244 (26.4) 2.09 (1.71–2.56) <  0.001
 Cough 630 (76.4) 511 (55.4) 2.60 (2.12–3.20) <  0.001
 Sore throat 546 (66.2) 689 (74.6) 0.66 (0.54–0.82) <  0.001
 Dyspnea 86 (10.4) 75 (8.1) 1.32 (0.95–1.82) 0.098
Time from onset of symptoms to admission, n (%)
 1 day 392 (47.5) 384 (41.6) 1  
 2 days 209 (25.3) 194 (21.0) 1.06 (0.83–1.34) 0.661
 3 days 138 (16.7) 158 (17.1) 0.86 (0.65–1.12) 0.254
  ≥ 4 days 86 (10.4) 187 (20.3) 0.45 (0.34–0.60) <  0.001
 Time from onset of symptoms to admission, median (range) 2 (0–6) 2 (0–7) 0.85 (0.80–0.91) <  0.001
Length of hospital stay, n (%) b
 0–4 days 254 (30.8) 342 (37.1) 1  
 5 days 155 (18.8) 128 (13.9) 1.63 (1.23–2.17) <  0.001
 6–7 days 261 (31.6) 259 (28.1) 1.36 (1.07–1.72) <  0.001
 Median length of hospital stay (range) 6 (0–35) 5 (0–31) 1.00 (0.98–1.04) 0.627
 Intensive care unit admission, n (%) 1 (0.1) 2 (0.2) 0.56 (0.05–6.17) 0.635
Pregnancy outcome, n (%)
 Aborted (<  20 weeks) 14 (1.7) 39 (4.2) 0.39 (0.21–0.73) 0.003
 Stillborn (≥ 20 weeks) 12 (1.5) 11 (1.2) 1.22 (0.54–2.79) 0.631
 Live delivery during the current admission, n (%) 78 (9.5) 99 (10.7) 0.87 (0.64–1.19) 0.379
 Preterm (< 37 weeks) c 17 (21.8) 19 (19.2) 1.17 (0.56–2.45) 0.669
 Cesarean‡ 14 (17.9) 16 (16.2) 1.13 (0.52–2.50) 0.753
 Low birth weight (<  2500 g) c 3 (3.8) 12 (12.1) 0.29 (0.08–1.07) 0.062
Discharge diagnosis, n (%)
 Influenza 617 (74.8) 108 (11.7) 23.34 (18.07–30.13) <  0.001
 Pneumonia 9 (1.1) 13 (1.4) 0.77 (0.33–1.82) 0.553
 Respiratory disease 187 (22.7) 736 (79.7) 0.74 (0.06–0.09) <  0.001
 Other 12 (1.5) 66 (7.2) 0.19 (0.10–0.36) <  0.001
  1. aEstimated by exact logistic regression
  2. bProportions are relative to deliveries during the current admission
  3. N = 825 for influenza positive, N = 922 for influenza negative