TABLE 2.

Trends in Birth Prevalence (Prev) of Congenital Spastic CP Per 1000 1-y Survivors by Birth Weight and Gestational Age, Birth Years 1985 to 2002^a

Characteristic	1985		1986		1988		1992		1994		1996		1998		2000		2002		PR (95% CI)a	Average Annual Change, % (95% CI)
	n	Prev	n	Prev	n	Prev	n	Prev	n	Prev	n	Prev	n	Prev	n	Prev	n	Prev
Birth weight overall, g	57	1.87	64	1.99	45	1.25	62	1.6	76	1.9	75	1.9	87	2.0	87	1.8	87	1.7		0.28 (−1.24 to 1.82)
<1500	21	65.63	23	65.71	14	37.74	22	44.4	32	66.4	28	54.8	44	66.4	37	53.7	28	40.8	68.0 (57.4 to 80.6)	−0.73 (−3.2 to 1.82)
1500 to 2499	15	8.16	14	7.09	7	3.10	18	7.1	14	5.5	11	4.1	13	4.4	11	3.3	22	6.2	6.6 (5.3 to 8.1)	−2.02 (−5.56 to 1.66)
≥2500	21	0.74	27	0.91	24	0.72	22	0.6	30	0.8	36	1.0	30	0.7	39	0.9	37	0.8	Referent	0.46 (−1.03 to 1.98)
Gestational age	55	1.88	57	1.84	40	1.23	62	1.65	76	1.94	74	1.83	87	1.96	87	1.76	87	1.74		0.46 (−1.01 to 1.95)
overall, wks
<32	21	47.95	18	40.91	13	29.68	26	39.8	35	56.3	30	47.7	41	54.7	37	46.1	26	34.6	51.1 (43.1 to 60.6)	0.34 (−1.03 to 1.98)
32 to 36	12	4.33	9	3.03	2	0.58	12	3.1	13	3.5	8	2.1	15	3.5	14	3.0	19	3.8	3.4 (2.8 to 4.3)	1.44 (−3.26 to 6.37)
≥37	22	0.85	30	1.13	25	0.87	24	0.7	28	0.8	36	1.0	31	0.8	36	0.8	42	0.9	Referent	−0.34 (−1.93 to 1.28)

^aNormal birth weight (≥2500 g) and term gestational age (≥37 wks) served as referent groups for their respective analyses.