Table 3:

Geometric mean concentration (GMC) of anti-pertussis toxin (PT) IgG in maternal and cord blood stratified by gestational week at Tdap vaccination and time interval between vacination and delivery.

			Maternal anti-PT IgG	p-value*	Cord blood anti-PT IgG	p-value*	Ratio ** (95% CI)
	N	%	GMC (95% CI)		GMC (95% CI)
Gestational Week
Mean (SD)	30.1 (3.2)
17|-|26	21	8.6	72.7 (58.3-90.6)	0.764	114.3 (95.4-136.9)	0.060	1.6 (1.4-1.8)
27|-|29	87	35.8	64.5 (54.1-76.8)		100.1 (83.6-119.8)		1.5 (1.4-1.7)
30|-|33	97	40.0	64.6 (54.4-76.6)		84.9 (72.2-99.9)		1.3 (1.2-1.4)
34|-|40	38	15.6	73.7 (56.9-95.4)		70.4 (51.7-96.1)		1.0 (0.8-1.1)
Time interval between vaccination and delivery (days)
Mean (SD)	65.0 (22.1)
15|-|30	17	7.0	74.7 (50.2-111.2)	0.411	54.0 (34.4-84.8)	0.006***	0.8 (0.6-0.9)
31|-|60	77	31.7	66.4 (54.8-80.6)		82.8 (68.2-100.5)		1.2 (1.1-1.3)
61|-|90	128	52.7	62.9 (54.7-72.3)		93.6 (81.7-107.2)		1.5 (1.4-1.6)
≥ 91	21	8.6	86.1 (64.8-114.7)		141.2 (101.1-197.1)		1.6 (1.4-1.9)

^*Kruskal Wallis test

^**p<0.001

^***15|-|30 vs 61|-|90 p= 0.014; 15|-|30 vs ≥ 91p= 0.001; 31|-|60 vs ≥ 91 p= 0.016