. Author manuscript; available in PMC: 2011 Aug 1.

Published in final edited form as: Am J Perinatol. 2011 Mar 4;28(7):571–578. doi: 10.1055/s-0031-1274511

Table 3.

Birth weight and birth weight centile by caffeine, paraxanthine and caffeine to paraxanthine ratio quartiles.

	Quartile				p Value^*	p for trend
	1^st	2^nd	3^rd	4^th	p Value^*	p for trend
Caffeine	3301 (612)	3327 (647)	3257 (614)	3266 (532)	0.4	0.7
Caffeine	56.7 (27.4)	52.3 (31.5)	56.0 (29.5)	50.3 (26.7)	0.4	0.4
Paraxanthine	3263 (703)	3367 (471)	3318 (657)	3205 (540)	0.2	0.5
Paraxanthine	54.8 (29.2)	56.6 (29.1)	56.1 (28.7)	47.9 (28.0)	0.3	0.2
Caffeine to paraxanthine ratio	3245 (600)	3282 (621)	3184 (669)	3440 (478)	0.08	0.2
Caffeine to paraxanthine ratio	52.4 (29.6)	53.8 (28.7)	50.8 (29.0)	58.4 (28.0)	0.4	0.4

p Value is from the F-statistic in the analysis of covariance model adjusted for maternal age at sampling and pre-pregnancy BMI. Birth weight centile additionally adjusted for race, sex and gestational age at delivery.

S.D., standard deviation

Birth weight centile additionally adjusted for race, sex and gestational age at delivery.

Birth weight (S.D.) – grams

Birth weight centile (S.D.) – %