Congenital central nervous system malformations in Hunan Province, China, 2016-2020

Abstract

Background This study aimed to analyze the epidemiological characteristics of congenital central nervous system (CNS) malformations, provide some information for intervention programs to reduce the incidence of CNS malformations. Methods Data were obtained from the Birth Defects Surveillance System in Hunan Province, China, 2016–2020. Incidences of CNS malformations (number of cases per 1000 fetuses (births and deaths at 28 weeks of gestation and beyond)) with 95% confidence intervals (CI) were calculated by year, gender, residence, and maternal age. Crude odds ratios (ORs) were calculated to examine the association of each maternal characteristic with CNS malformations. Results A total of 847755 fetuses (births and deaths)were registered, and 23420 birth defects were identified, including 1484 CNS malformations (which accounted for 6.34% of all birth defects). The incidence of CNS malformations was 1.75‰ (95%CI: 1.66,1.84). The incidence of CNS malformations at 28 weeks of gestation and beyond was 0.35‰ (95%CI: 0.31,0.39) (297 cases). The most frequent CNS malformations were hydrocephalus (462 cases, 31.13%), anencephaly (243 cases, 16.37%), spina bifida (220 cases, 14.82%), encephalocele (184 cases, 12.4%), holoprosencephaly (132 cases, 8.89%), cerebellar malformation (91 cases, 6.13%), corpus callosum agenesis (85 cases, 5.73%). CNS malformations were more common in males than females (1.53‰ vs. 1.28‰, OR=1.20, 95%CI: 1.07-1.34). Anencephaly (0.19‰ vs. 0.12‰, OR=1.59, 95%CI: 1.11-2.28) and corpus callosum agenesis (0.12‰ vs. 0.07‰, OR=1.69, 95%CI: 1.07-2.67) were more common in males than females, too. Holoprosencephaly was more common in urban than rural areas (0.19‰ vs. 0.13‰, OR=1.43, 95%CI: 1.02-2.02). Compared to mothers 25-29 years old, mothers <20 years old (OR=1.80, 95%CI: 1.31-2.46), 20-24 years old (OR=1.18, 95%CI: 1.01-1.37), and ≥35 years old (OR=1.17, 95%CI: 1.01-1.37) were risk factors for CNS malformations; And mothers <20 years old was a risk factor for anencephaly (OR=2.51, 95%CI: 1.31-4.80) and encephalocele (OR=2.73, 95%CI: 1.37-5.43); Mothers 20-24 years old (OR=1.41, 95%CI: 1.09-1.82) or ≥35 years old (OR=1.39, 95%CI: 1.07-1.81) were risk factors for hydrocephalus. The pregnancy outcomes of most CNS malformations were deaths (1421 cases, 95.75%), and most CNS malformations-related deaths were therapeutic terminations (98.45%, 1399/1421). Conclusion In summary, we have described the epidemiological characteristics of CNS malformations. Several mechanisms have been proposed to explain these phenomena. Our study is of great significance for CNS malformation intervention programs to reduce the incidence of CNS malformations.