Table 5.

Regression model testing main and interactive effects of blood Hg (μg/L) and GSTM1 or GSTT1 genotype on birth weight.

	Early pregnancy		Late pregnancy		Cord blood
Model	β	p-Value	β	p-Value	β	p-Value
Model 1: GSTM1 interaction
Hg level (≥ 90th vs. < 90th)	−114.9	0.18	−197.6	0.01	−215.4	0.007
GSTM1 (present vs. null type)	−339.3	0.04	−272.8	0.07	−260.4	0.08
Interaction term of GSTM1*Hg level	298.5	0.04	243.8	0.06	231.3	0.07
Model 2: GSTT1 interaction
Hg level (≥ 90th vs < 90th)	−73.7	0.40	−80.6	0.34	−64.8	0.43
GSTT1 (present vs. null type)	−196.8	0.22	137.6	0.39	152.5	0.30
Interaction term of GSTT1*Hg level	158.0	0.26	−154.9	0.27	−166.3	0.20

Adjusted for gestational age, prepregnancy BMI, maternal age, mother’s educational level, infant sex, parity, and weight gain during pregnancy.