Possible Roles of Proinflammatory and Chemoattractive Cytokines Produced by Human Fetal Membrane Cells in the Pathology of Adverse Pregnancy Outcomes Associated with Influenza Virus Infection

Table 2

Number of deliveries, gestational age, mode of delivery, and neonatal outcome in pregnancies affected by 2009 H1N1 influenza.

Papers	No. of deliveries	Proportion of preterm deliveries	Proportion of cesarean deliveries	Fetal/neonatal survival
United States of America
CDC, 2010 [32]	9	5/9 (56%)	4/9 (44%)	1 stillbirth, 1 neonatal death
Creanga et al., 2010 [17]	22 while ill; 22 after recovery	6/44 (14%); While ill: 3/22 (2 in women with severe disease); After recovery: 3/22	While ill: 11/22 (50%); After recovery: 7/22 (32%)	2 neonatal deaths
Jamieson et al., 2009 [21]	6^‡	6/6 (100%)	6/6 (100%; 5 in cases with maternal death)	1 PROM
Louie et al., 2010 [29]	35	3/35 (9%) second trimester (25–28 weeks) 32/35 (91%) third trimester (>28 weeks)	At least 9, including 4 in ICU	11 NICU admissions
Miller et al., 2010 [33]	7	6/7 (86%)	4/7 (57%)	2 spontaneous abortion
Siston et al., 2010 [30]	169	51/169 (30%)	109/188 (58%)
Australia
ANZIC, 2010 [15]	59	22/60^† (36.7%); 11 (32–36 weeks); 11 (20–31 weeks)	While ill: 13/14 (93%) in ICU; After recovery: 6/23 (26%)	4 stillbirths, 3 infant deaths; 32 NICU admissions
Hewagama et al., 2010 [34]	15	6/15 (40.0%)		2 stillbirths, 1 neonatal death due to prematurity
France (La Reunion)
		17/115 (14.8%)		13 PTL concomitant to flu, 1 PROM concomitant to flu, no adverse neonatal outcome
Gérardin et al., 2010 [19]	115	3 very preterm (<33 weeks)	21/114 (18%)
		14 late preterm (33–36 weeks)
United Kingdom
Yates et al., 2010 [31]	152	45/152 (30%); (OR, 5.5; CI 3.7–8.3)		6 stillbirths
Pierce et al., 2011 [37]	256	59/251 (23.7%); (aOR, 4.0; CI, 2.7–5.9; P = 0.046)	100/250 (40.0%); (aOR, 2.3; CI, 1.7–3.2)	5 loss of pregnancy before 24 weeks, 7 stillbirths; (aOR, 4.2; CI, 1.4–12.4; P = 0.001), 3 neonatal death; (aOR, 5.6; CI, 0.5–64.2); 10 perinatal death (aOR, 5.7; CI, 2.2–15.1), 94 low birth weight (aOR, 3.2; CI, 2.1–4.9)
Singapore
Lim et al., 2010 [35]	42^*	13/42 (31%)	6/42 (14%)
Israel
Honarvar et al., 2010 [36]	6	1/6 (17%)	5/6 (83%)	1 neonatal death due to H1N1 infection^¶
India
Pramanick et al., 2011 [38]	13	5/13 (38%)	11/13 (85%)	1 abortion
Japan
Nakai et al., 2011 [39]	181	5/178 (3%) (22–31 weeks); 21/178 (12%) (32–36 weeks)		3 abortions
Brazil
Figueiró-Filho et al., 2011 [40]	31	9/31 (29%)	19/31 (61%)	3 neonatal death
Turkey
Özyer et al., 2011 [41]	10	4/11 (36%)
Canada
Oluyomi-Obi et al., 2010 [42]	6	1/6 (17%; ≤14 weeks); 1/6 (17%; 15–28 weeks); 4/6 (66%; ≥29 weeks)	3/6 (50%)	1 PPROM, 1 PTL, 1 stillbirth, 3 NICU admission, 1 neonatal death

Abbreviations used: ANZIC: ANZIC Influenza Investigators and Australasian Maternity Outcomes Surveillance System; aOR: adjusted odds ratio; CDC: Centers for Disease Control and Prevention; CI: 95% confidence interval; ICU: intensive care unit; NICU: neonatal ICU; OR: odds ratio; PROM: preterm rupture of membranes; PTL: preterm labor. Superscript: ^aNumber of deliveries of fetuses of potentially viable gestational age (definition varied by study). Symbol: ^*excluded 5 spontaneous and iatrogenic abortions; ^†includes one set of twins; ^‡all of 6 were fatal cases; ^§127 with PCR-confirmed 2009 H1N1 influenza; ^¶confirmed by RT-PCR. This table is reproduced from Mosby et al. [14] with minor modifications, and the other reports from India, Japan, Brazil, Turkey, and Canada are added in the original table.