Table 2.

Characteristics of the sample (mean±SD) for baseline variables at the different time points.

Characteristic/variable	Baseline (n=59)	12 months (n=50)	18 months (n=46)	p value
Birth weight (grams)	1713.8±1242.5	1709.5±1087.7	1708.2±907.7	NS
Gestational age (weeks)	31.2±3.6	30.5±3.8	31.7±4.2	NS
APGAR score (5 min)	6.2±3.5	6.1±3.9	6.6±3.2	NS
Head circumferencea	30.5±6.6	30.2±8.5	31.6±7.8	NS
Male/female	34/25	27/23	24/22	NS
Prenatal care (2nd trimester)	43 of 59	39 of 50	37 of 46	NS
Maternal age (years)	27.1±3.7	29.2±3.7	28.8±3.4	NS
Maternal education (NGrade 12)	25 of 59	22 of 50	20 of 46	NS
Days in hospital	66.3±10.5	68.9±9.6	69.1±10.2	NS
Hispanic	42 of 59	34 of 50	26 of 46	NS
Parental Stress Index	75.8±11.9	77.6±16.9	76.6.±19.8	NS
Perceived Social Support	69.2±12.8	65.6±9.4	64.8±10.6	NS
Mother/infant interaction	61.3±8.2	59.9±9.1	60.2±10.2	NS
The HOME	34.2±5.5	35.7±5.3	37.2±7.4	NS
Bayley motor score	88.3±18.7	84.1±20.4	86.3±16.9	.05*
Bayley mental score	82.6±19.5	89.6±20.2	90.2±22.3	.04*

NS = not significant.

^*Wilcoxon p test significnt at p<.05.