Changes in detection of birth defects and perinatal mortality after introduction of prenatal ultrasound screening in the Kola Peninsula (North-West Russia): combination of two birth registries

Table 3 Actual number (N) and prevalence of perinatal deaths (per 1000 newborns) before and after the establishment of prenatal screening

Group of newborns	1973-2000		1990-2000		2001-2011		p-value¹
Group of newborns	N	Prevalence²	N	Prevalence²	N	Prevalence²	p-value¹
Newborns with BD (N = 1099)	87	106.6 (84.3-129.1)	18	52.9 (32.5-85.9)	6	21.2 (4.3-38.1)	<0.0001³
Newborns with BD (N = 1099)	87	106.6 (84.3-129.1)	18	52.9 (32.5-85.9)	6	21.2 (4.3-38.1)	0.0160⁴
Newborns without BD (N = 29 349)	419	18.2 (16.5-19.9)	105	16.5 (13.3-19.6)	60	9.5 (7.1-11.8)	<0.0001³
Newborns without BD (N = 29 349)	419	18.2 (16.5-19.9)	105	16.5 (13.3-19.6)	60	9.5 (7.1-11.8)	<0.0001⁴

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