Huang Yan, Tang Wen, Mu Yi, Li Xiaohong, Liu Zheng, Wang Yanping, Li Mingrong, Li Qi, Dai Li, Liang Juan, Zhu Jun
Nursing Department, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China.
National Office for Maternal and Child Health Surveillance of China, West China Second University Hospital, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, Sichuan University, Chengdu, Sichuan, China.
PLoS One. 2016 Dec 12;11(12):e0167575. doi: 10.1371/journal.pone.0167575. eCollection 2016.
The accuracy of a population-based sex ratio at birth (SRB) in China has long been questioned. To depict a more accurate profile, the present study used data from a national surveillance system for health facility births to explore the characteristics of SRB in China.
Data from China's National Maternal Near Miss Surveillance System between 2012 and 2015 were used. We restricted the analysis to live births of ≥28 completed gestational weeks or ≥1000 g birth weight. The strength of association between obstetric characteristics and SRB was examined using logistic regression, taking into account the sampling strategy and clustering of births within health facilities.
There were 2,785,513 boys and 2,549,269 girls born alive between 2012 and 2015 in 441 health facilities. The SRB was 111.04 in 2012, 110.16 in 2013, 108.79 in 2014, and 109.53 in 2015. The SRB was high in the eastern region, especially in rural areas. The SRBs increased with mother's age and decreased with mother's education. The SRB in women who were pregnant for the first time was 104.30. The SRB in primipara was normal (104.35), but it was extremely high in non-primipara, especially for women with three or more parities (141.76); only 5.26% of live births fell within this group. The SRBs increased significantly by the number of parities, especially in the rural areas of the central region. After adjustment for sociodemographic factors, women with three or more parities were 1.39 (95% CI 1.34, 1.43) times more likely to give birth to a boy compared with primiparae who were pregnant for the first time.
Our analysis suggests that the SRB was lower than what was reported officially but higher than normal. The government should keep strengthening supervision to prevent sex-selection, especially in the wake of the two-child policy implemented in 2015.
中国基于人群的出生性别比（SRB）的准确性长期以来一直受到质疑。为了描绘更准确的情况，本研究使用了国家卫生机构出生监测系统的数据来探讨中国的出生性别比特征。
使用了2012年至2015年中国国家孕产妇严重病例监测系统的数据。我们将分析限制在妊娠满28周或出生体重≥1000克的活产儿。使用逻辑回归分析产科特征与出生性别比之间的关联强度，同时考虑到抽样策略和卫生机构内出生的聚集性。
2012年至2015年期间，441家卫生机构中有2785513名男婴和2549269名女婴存活。2012年出生性别比为111.04，2013年为110.16，2014年为108.79，2015年为109.53。东部地区出生性别比偏高，尤其是农村地区。出生性别比随母亲年龄增加而升高，随母亲受教育程度降低而升高。首次怀孕妇女的出生性别比为104.30。初产妇的出生性别比正常（104.35），但非初产妇的出生性别比极高，尤其是有三个或更多孩子的妇女（141.76）；该组活产儿仅占5.26%。出生性别比随产次显著升高，尤其是中部地区农村。在调整社会人口学因素后，有三个或更多孩子的妇女比首次怀孕的初产妇生男孩的可能性高1.39倍（95%可信区间1.34，1.43）。
我们的分析表明，出生性别比低于官方报告，但高于正常水平。政府应继续加强监管以防止性别选择，特别是在2015年实施二孩政策之后。
