Table 2 Linear regression models for the association of duration to achieve a normal Apgar score and mean reduction in cognitive score

Time to reach an Apgar score of >6 (min)	Measures of cognition										Measure of educationSchool grade(n = 167 117)
	Logic score(n = 134 596)		Synonym score(n = 133 858)		Spatial score(n = 133 825)		Technical score(n = 124 149)		IQ score(n = 136 788)		Measure of educationSchool grade(n = 167 117)
	Mean reduction (z-score)	p*	Mean reduction (z-score)	p*	Mean reduction (z-score)	p*	Mean reduction (z-score)	p*	Mean reduction (z-score)	p*	Mean reduction (z-score)	p*
Unadjusted
<1	Ref		Ref		Ref		Ref		Ref		Ref
1–5	0.017 (−0.014–0.048)	0.006	−0.014 (−0.043–0.015)	0.991	−0.017 (−0.048–0.015)	0.040	0.045 (0.013–0.076)	<0.001	0.013 (−0.017–0.043)	0.023	−0.005 (−0.032–0.022)	0.019
>5	0.107 (0.036–0.179)		0.038 (−0.028–0.105)		0.108 (0.035–0.181)		0.094 (0.022–0.167)		0.091 (0.021–0.161)		0.129 (0.067–0.192)

Adjusted for antenatal†§ factors
<1	Ref		Ref		Ref		Ref		Ref		Ref
1–5	0.036 (0.005–0.067)	<0.001	0.011 (−0.018–0.039)	0.087	−0.001 (−0.032–0.031)	0.040	0.057 (0.026–0.089)	<0.001	0.035 (0.005–0.065)	<0.001	0.011 (−0.016–0.038)	0.001
>5	0.120 (0.049–0.191)		0.061 (−0.005–0.127)		0.119 (0.047–0.192)		0.100 (0.028–0.173)		0.109 (0.039–0.178)		0.138 (0.076–0.200)

Adjusted for antenatal† and intrapartum/neonatal factors‡
<1	Ref		Ref		Ref		Ref		Ref		Ref
1–5	0.039 (0.008–0.070)	<0.001	0.016 (−0.013–0.045)	0.037	−0.003 (−0.034–0.029)	0.057	0.058 (0.026–0.089)	<0.001	0.039 (0.009–0.069)	<0.001	0.019 (−0.008–0.046)	<0.001
>5	0.123 (0.052–0.194)		0.067 (0.001–0.133)		0.116 (0.043–0.188)		0.096 (0.024–0.169)		0.112 (0.042–0.181)		0.145 (0.083–0.207)

Adjusted for antenatal†, intrapartum/neonatal factors‡ and social factors§
<1	Ref		Ref		Ref		Ref		Ref		Ref
1–5	0.034 (0.005–0.063)	0.001	0.011 (−0.015–0.038)	0.169	−0.007 (−0.037–0.024)	0.188	0.052 (0.022–0.083)	<0.001	0.033 (0.005–0.061)	0.001	0.010 (−0.015–0.034)	0.002
>5	0.092 (0.025–0.158)		0.036 (−0.025–0.097)		0.091 (0.021–0.161)		0.071 (0.001–0.140)		0.081 (0.017–0.145)		0.109 (0.053–0.166)

*p for trend.
†Parity, pre-eclampsia, birth weight, length and head circumference.
‡Mode of delivery, maternal or infant infection, season and year of birth.
§Maternal and paternal education status, occupation and age.