Table II.

Group Differences for Outcome and Mediator Variables

	Abstainers		Light users		Heavy users		F
	M	SD	M	SD	M	SD
Mediator variables
Birth weight (grams)	3353.85a	548.6	2903.27a	556.35	2811.09a	486.03	12.37**
Birthlength (centimeters)	49.62a	3.31	48.57a	2.45	46.98a	2.61	6.54**
Birth head circumference (centimeters)	33.66a	1.45	33.01	1.48	32.84a	1.47	3.64*
Total number of cigarettes smoked during pregnancy	522.39a	1013.45	1571.5a	1549.54	2361.32a	2077.19	16.13**
Total number of standard drinks	10.54a	39.27	95.1a	234.7	524.05a	871.63	5.92**
Number of days 5 or more drinks were consumed	1.06a	3.99	4.29a	11.91	52.32a	89.65	17.74**
Total number of joints during pregnancy	71.85	349.61	57.14	129.46	37.05	77.4	.17
Outcome variables
Heart rate (bpm)	134.06a	139.20	143.1a	150.21	148.86a	158.53	21.43*
Respiratory sinus arrhythmia	.019	.038	.019	.031	.010	.017	2.76, p = .06

^aWhere the significant differences lie.

^*p < 0.05.

^**p < 0.01.