To explore the incidence, diagnosis and sequelae of congenital hydrocephalus (CH) fetus and infants of Beijing by analyzing monitoring data of CH in Beijing in nearly 5 years.

From January 2015 to December 2019, a total of 407 CH fetuses or infants in the Birth Defects Monitoring Network in Beijing from 13 weeks of gestation to 1 year after birth were selected as research subjects. Their birth defects diagnosis data were analyzed. Chi-square test was used to statistically compare the survival rate between isolated and non-isolated CH of live born infants within 0-1 year after birth. The procedures followed in this study were in line with World Medical Association Declaration of Helsinki revised in 2013.

The incidence of CH in fetuses and infants within 1 year after birth in nearly 5 years in Beijing was 3.60×10^-4 (407/1 129 861). Among 407 cases of CH fetuses or infants, 82 cases (20.15%) were complicated with extracranial malformation, and 20 cases (4.91%) were complicated with chromosome abnormalities. The prenatal diagnosis rate of CH fetus was 92.38%(376/407). When fetus diagnosed with CH by fetal ultrasound, their gestational age was 24 gestational weeks (23-35 gestational weeks), and fetus of gestational age ≥28 weeks were accounted for 26.06% (98/376) of the prenatal diagnosed cases. Among 376 CH fetuses diagnosed prenatally, 44 cases were examined by prenatal fetal ultrasound and magnetic resonance imaging (MRI), and 4 cases were diagnosed supplementary specific types of intracranial malformations by fetal MRI. No intrauterine infection of pregnant women was found in this study. Among 103 CH cases of live births, the survival rate within 1 year after birth of 73 infants with isolated CH was 72.6% (53/73), the survival rate of 30 infants with non-isolated CH was 60.0% (18/30), but the difference was not statistically significant (P>0.005).

In three-level prevention and control system to prevent birth defects, the primary and secondary prevention for CH fetuses or infants in Beijing has achieved results. Multiple dynamic fetal ultrasound examinations for pregnant women during pregnancy, combined with fetal MRI if necessary, and cytogenetic and molecular genetic examinations for non-isolated CH fetus may improve the prevention effects of CH.