Table 1. The prevalence and time trends of neural tube defects (per 10,000 births).

	Year										Overall	AverageChange (%)	Pvalue	95% CI
	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015
NTDs	28.8	29.3	23.4	21.1	17.7	18.3	16.9	15.2	12.9	7.5	19.1	−10.68	<0.001	−13.32, −7.97
Multiple NTDs	4.0	3.7	2.5	3.2	3.4	2.5	2.2	1.7	1.3	0.6	2.5	−12.19	0.001	−17.49, −6.55
Isolated	26.3	25.7	20.8	18.5	15.5	14.9	14.0	12.1	10.8	6.1	16.5	−11.93	<0.001	−14.13, −9.66
Non-isolated	2.5	3.5	2.6	2.7	2.3	3.4	2.9	3.1	2.1	1.4	2.7	−3.15	0.25	−8.79, 2.84
Anencephaly	7.4	7.1	5.6	5.2	5.5	5.2	4.1	4.4	3.0	1.8	4.9	−10.15	<0.001	−13.60, −6.56
Isolated	6.1	5.6	4.9	4.0	3.9	3.9	3.3	3.6	2.5	1.5	3.9	−10.33	<0.001	−13.38, −7.17
Non-isolated	1.3	1.5	0.7	1.2	1.5	1.3	0.8	0.8	0.5	0.3	1.0	−9.52	0.04	−17.49, −0.77
Spina bifida	9.6	9.5	7.6	6.8	6.7	6.5	5.2	4.4	3.8	2.3	6.2	−11.57	<0.001	−14.19, −8.88
Isolated	5.1	5.3	4.6	3.2	2.9	3.2	2.3	1.8	2.1	1.3	3.2	−13.06	<0.001	−16.02, −10.00
Non-isolated	4.6	4.2	3.0	3.6	3.9	3.3	2.9	2.6	1.7	1.0	3.1	−9.88	0.003	−14.73, −4.75
Encephalocele	1.1	1.5	1.3	1.5	1.3	1.1	1.2	1.4	1.2	0.8	1.2	−2.57	0.21	−6.74, 1.80
Isolated	0.8	1.1	1.0	1.0	1.1	0.8	0.8	1.1	1.0	0.6	0.9	−1.19	0.55	−5.65, 3.47
Non-isolated	0.4	0.4	0.3	0.5	0.2	0.3	0.3	0.3	0.2	0.2	0.3	−6.39	0.06	−12.85, 0.55
CH	14.6	14.9	11.5	10.9	7.7	8.0	8.6	6.8	6.2	3.2	9.3	−11.84	<0.001	−15.03, −8.52
Isolated	10.7	10.4	8.3	7.5	4.6	5.0	5.6	4.2	4.2	2.2	6.3	−13.24	<0.001	−16.57, −9.77
Non-isolated	4.0	4.5	3.1	3.4	3.1	3.0	3.1	2.6	2.0	1.0	3.0	−8.79	0.002	−13.10, −4.26

CI, confidence interval; CH, congenital hydrocephalus.