Epidemiological characteristics of holoprosencephaly in China, 2007-2014: A retrospective study based on the national birth defects surveillance system

Objective
To describe the epidemiology of holoprosencephaly (HPE) in China with special reference to prevalence and associated anomalies.
Methods
Data were abstracted from the Chinese Birth Defects Monitoring Network for the period 2007–2014. Birth prevalence of HPE were assessed by birth year, fetal/infant sex, maternal age, and maternal residential area. Poisson regressions were used to calculate the crude and adjusted prevalence ratios (PR) and their 95% confidence intervals, and linear chi-square test was used to explore time trend for the prevalence of HPE.
Results
A total of 1222 HPE cases were identified in 13,284,142 births, yielding an overall prevalence of 0.92 per 10,000 births. The annual prevalence of HPE presented an upward trend (P<0.001), from 0.54 per 10,000 births in 2007 to 1.21 per 10,000 births in 2014. Higher prevalence was found in older maternal-age groups (30–34 years, adjusted PR: 1.19, 95% CI: 1.02–1.40; ≥35 years, adjusted PR: 1.53, 95% CI: 1.26–1.86) in comparison with the maternal-age group of 25 to 29 years. Higher prevalence was also found in infants born to mothers resided in urban areas (adjusted PR: 1.23, 95% CI: 1.08–1.39) and female infants (adjusted PR: 1.30, 95% CI: 1.15–1.47).
Conclusions
HPE is an important perinatal health issue because of its poor prognosis. This is the first study depicting a picture of epidemiological characteristics of HPE in China, which can provide useful references for future studies.