Table 2.

Incidence rates, rate differences (RD), and rate ratios (RR) of infant outcomes associated with receipt of Tdap during pregnancy at 7 Vaccine Safety Datalink sites, 2010–2013, (N = 197,564), by time period during pregnancy in which Tdap was administered and limiting results to infants born < 34 weeks gestation.

	Maternal Tdap administration during pregnancy at any time during pregnancy, 2010–2013				Adjusted measures of association 95% CI
	No (n = 152,556)		Yes (n = 45,008)
	n	Incidence rate %	n	Incidence rate %	RD in cases per 100 live births	RR
Chorioamnionitis	7970	5.22	2883	6.41	1.16 (0.9, 1.42)	1.23 (1.17, 1.28)
Composite outcome	4824	3.16	1288	2.86	0.11 (−0.07, 0.29)	1.04 (0.98, 1.11)
TTN^a	3524	2.31	973	2.16	0.07 (−0.09, 0.22)	1.03 (0.96, 1.11)
Neonatal sepsis^b	939	0.62	231	0.51	0.03 (−0.05, 0.10)	1.06 (0.91, 1.23)
Pneumonia^c	371	0.24	73	0.16	0.00 (−0.04, 0.04)	0.94 (0.72, 1.22)
RDS^d	215	0.14	49	0.11	−0.01 (−0.05, 0.03)	0.91 (0.66, 1.26)
Convulsions in newborn^e	261	0.17	68	0.15	0.02 (−0.02, 0.06)	1.16 (0.87, 1.53)
	Maternal Tdap administration during recommended time period of pregnancy, 27–36 weeks, 2010–2013
	No (n = 133,882)		Yes (n = 22,772)
	n	Incidence rate %	n	Incidence rate %	RD in cases per 100 live births	RR

Chorioamnionitis	7109	5.31	1430	6.28	0.98 (0.65,1.32)	1.20 (1.14, 1.28)
Composite outcome	4157	3.10	653	2.87	0.13 (−0.11, 0.37)	1.02 (0.94, 1.12)
TTN	3061	2.29	520	2.28	0.20 (−0.02, 0.41)	1.08 (0.98, 1.19)
Neonatal sepsis	785	0.59	101	0.44	−0.01 (−0.11, 0.08)	0.90 (0.73, 1.11)
Pneumonia	329	0.25	34	0.15	−0.01 (−0.06, 0.05)	0.82 (0.57, 1.17)
RDS	168	0.13	21	0.09	−0.02 (−0.06, 0.03)	0.79 (0.50, 1.26)
Convulsions in newborn	229	0.17	28	0.12	−0.01 (−0.06, 0.04)	0.88 (0.58, 1.31)
	Maternal Tdap administration at any time during pregnancy, infants born < 34 weeks GA
	No (n = 2711)		Yes (n = 426)
	n	Incidence rate %	n	Incidence rate %	RD in cases per 100 live births	RR

Chorioamnionitis	221	8.15	28	6.57	−1.02 (−3.51, 1.47)	0.87 (0.59, 1.30)
Composite outcome	695	25.64	104	24.41	0.18 (−4.20, 4.57)	1.02 (0.83, 1.26)
TTN	291	10.73	51	11.97	0.84 (−2.48, 4.15)	1.07 (0.79, 1.45)
Neonatal sepsis	318	11.73	48	11.27	0.85 (−2.22, 3.93)	1.11 (0.81, 1.51)
Pneumonia	121	4.46	9	2.11	−0.95 (−2.76, 0.86)	0.60 (0.30, 1.19)
RDS	46	1.70	5	1.17	−0.26 (−1.59, 1.07)	0.84 (0.33, 2.14)
Convulsions in newborn	40	1.48	5	1.17	−0.12 (−1.49, 1.24)	0.98 (0.38, 2.50)

TTN = transient tachypnea of the newborn; RDS = respiratory distress syndrome.

ICD-9 code 770.6.

ICD-9 codes 771.8, 771.81, 995.92, & 771.89.

ICD-9 codes 770.0 & 480.0–486.

ICD-9 codes 769, 770.84, & 770.87.

ICD-9 code 779.