Table 2a. Rates of IVH, severe IVH, survival, and IVH-free survival by birth weight.

	n		IVH			Grade III/IV IVH or death with no ultrasound performed			Survival			IVH-free survival
	Before	After	Before	After	p-value	Before	After	p-value	Before	After	p-value	Before	After	p-value
<500g	21	15	28.6%	20.0%	0.845	9.5%	6.7%	0.760	81.0%	86.7%	1.0	57.1%	80.0%	0.282
500 to 749g	67	39	37.3%	17.9%	0.061	14.9%	10.3%	0.669	89.6%	89.7%	0.765	58.2%	76.9%	0.082
750 to 999g	68	48	20.6%	10.4%	0.229	11.8%	2.1%	0.117	95.6%	93.8%	0.988	76.5%	83.3%	0.505
1000 to 1249g	46	48	13.0%	6.3%	0.442	8.7%	2.1%	0.333	95.7%	95.8%	0.640	84.8%	89.6%	0.698
1250 to 1499g	61	41	11.5%	4.9%	0.426	0.0%	0.0%		100.0%	97.6%	0.841	88.5%	92.7%	0.724
<1000g	156	102	28.8%	14.7%	0.013	12.8%	5.9%	0.11	91.0%	91.2%	0.856	66.0%	80.4%	0.018
<1500g	263	191	22.1%	10.5%	0.002	9.1%	3.7%	0.037	93.9%	93.7%	0.912	74.5%	85.3%	0.007

IVH: intraventricular hemorrhage; p-value: significance level