[1] Lu BY, Han B, Hu HW, Long W, Wang L, Cai ZM, et al. Changes in maternal age and its influences on maternal and neonatal complications under the two-child policy. Chin J Perinat Med 2019;22(3):157 − 63. https://doi.org/10.3760/cma.j.issn.1007-9408.2019.03.003CrossRef
[2] Xia SB, Meng C, Cheng X, Wang DD, Wu YX, Li ZW, et al. Trends in the prevalence of births with chromosomal abnormalities — Haidian district, Beijing Municipality, China, 2013–2022. China CDC Wkly 2023;5(36):791 − 6. https://doi.org/10.46234/ccdcw2023.152CrossRef
[3] Xu XL, Zuo HX, Shi ZM, Rao YS, Wang LL, Zeng H, et al. Determinants of second pregnancy among pregnant women: a hospital-based cross-sectional survey in China. BMJ Open 2017;7(3):e014544. https://doi.org/10.1136/bmjopen-2016-014544CrossRef
[4] Testa MR. On the positive correlation between education and fertility intentions in Europe: individual- and country-level evidence. Adv Life Course Res 2014;21:28 − 42. https://doi.org/10.1016/j.alcr.2014.01.005CrossRef
[5] Amwonya D, Kigosa N, Kizza J. Female education and maternal health care utilization: evidence from Uganda. Reprod Health 2022;19(1):142. https://doi.org/10.1186/s12978-022-01432-8CrossRef
[6] Sun SR, Dong W, Zhang S, Wang XJ, Wang P. Trend of maternal mortality ratio and death causes in Tianjin from 2011 to 2020. Chin J Perinat Med 2022;25(4):241 − 7. https://doi.org/10.3760/cma.j.cn113903-20210914-00792CrossRef
[7] Liang J, Mu Y, Li XH, Tang W, Wang YP, Liu Z, et al. Relaxation of the one child policy and trends in caesarean section rates and birth outcomes in China between 2012 and 2016: observational study of nearly seven million health facility births. BMJ 2018;360:k817. https://doi.org/10.1136/bmj.k817CrossRef
[8] Betran AP, Ye JF, Moller AB, Souza JP, Zhang J. Trends and projections of caesarean section rates: global and regional estimates. BMJ Glob Health 2021;6(6):e005671. https://doi.org/10.1136/bmjgh-2021-005671CrossRef
[9] Frick AP. Advanced maternal age and adverse pregnancy outcomes. Best Pract Res Clin Obstet Gynaecol 2021;70:92 − 100. https://doi.org/10.1016/j.bpobgyn.2020.07.005CrossRef
[10] Wang YX, He JB, Sun Y, Kaierdebieke A, Zhang SH, Liu NN, et al. Investigation and analysis of the status and demand of ″nutrition during pregnancy″ training in Beijing in 2022. Chin J Med Educ 2023;43(7):543 − 7. https://doi.org/10.3760/cma.j.cn115259-20221031-01374CrossRef