Table 2. The effect of exposure on the volume of fetal organs was assessed using a mixed model ANCOVA.

Volumes	p-values
	Exposure (Main Effect)	Exposure×Visit
Brain	0.020	0.079
Lung	0.018	0.166
Kidney	<0.001	0.001
Liver	0.106	0.152
Placenta	0.022	0.685
Total Fetal	0.003	0.009
Percentage Brain	0.051	0.473
Percentage Lung	0.564	0.735
Percentage Kidney	0.04	0.595
Percentage Liver	0.867	0.919

Each independent analysis included one within-subject variable of visit and one between-subject variable of exposure to maternal cigarette smoking, with four covariates.