{'fraction_non_alphanumeric': 0.04955872369314324, 'fraction_numerical': 0.03937542430414121, 'mean_word_length': 4.3992673992674, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Incidence of Down's Syndrome by Maternal Age of Asian Population

Objectives: To study the incidence of Down's syndrome by maternal age of the Asian population. 
 
Setting and Design: Data on prenatal serum screening between 2008-2017 was obtained from the Maternal and Child Hospital of Hubei Province. Cases were classified into three groups: ≤26-year-old, 27-33-year-old, and ≥34-year-old. The prevalence of Down's Syndrome was calculated for each age and age bracket separately, and the difference between different groups was analyzed with the chi-square test. 
 
Results: The incidence of Down’s syndrome in maternal age of ≤26-year-old, 27-33-year-old, and ≥34-year-old was 0.67 ‰, 0.29 ‰, and 2.07 ‰, respectively. There were significant differences among different age groups (χ 2 = 79.748, P < 0.05). 
 
Conclusion: In the population investigated, the incidence of Down’s syndrome in maternal age over 34 is much higher than that of the 27-33-year-old group, while younger women aged under 26 are also subject to a higher risk. 
 
Funding Statement: This work was supported by Hubei Provincial Health and Family Planning Scientific Research Project [Grant # WJ2018H0137]. 
 
Declaration of Interests: The authors have no conflicts of interest relevant to this article. 
 
Ethics Approval Statement: The research was approved by the Ethics Committee of Maternal and Child Health Hospital of Hubei Province. All patient guardians gave informed consent to the study.