Table 2.

The safety of IIV3-vaccination of pregnant women in preventing fetal death, preterm births, low birth weight, and small for gestational age outcomes for mothers who were administered vaccine or placebo on or before 34 weeks gestation.

Outcome	IIV3 Vaccine		Placebo		IRR (95%CI)	P
	N a	Rate a	N a	Rate a
Over The Duration Of Mother’s Enrollment Until Delivery
Fetal Death b	16	69.1	13	57.1	1.21 (0.58, 2.52)	0.61
Preterm Birth c	100	446.3	80	365.1	1.22 (0.91, 1.64)	0.18
Low Birth Weight c,d	123	549.0	107	488.3	1.12 (0.87, 1.46)	0.38
Small for Gestational Age (SGA) c,e,f	156	697.0	138	629.7	1.11 (0.88, 1.39)	0.38
In Women At Risk During The Influenza Seasons
Fetal Death b	13	58.8	11	50.8	1.16 (0.52, 2.58)	0.72
Preterm Birth c	77	356.8	61	290.2	1.23 (0.88, 1.72)	0.23
Low Birth Weight c,d	105	486.6	85	404.3	1.20 (0.90, 1.60)	0.20
Small for Gestational Age (SGA) c,e,f	149	691.3	130	618.4	1.12 (0.88, 1.41)	0.35

^aN = number of fetal outcomes; Rate per 1000 person-years of mother’s study participation until delivery.

^bN = total number of subjects without regard to their gestational stage at vaccine or placebo administration.

^cUsing only live births; excluded 1 subject whose gestational age of 21 weeks at birth was incongruent with her birth weight of 3185 g.

^dLBW is < 2500 g.

^e<10th percentile weight for GA.

^fSex was missing for one subject and thus percent weight for gestational age could not be computed for that subject.