1. Mathews TJ, Hamilton BE. First births to older women continue to rise. NCHS data brief, no 152. Hyattsville, MD: National Center for Health Statistics. 2014.
2. Khandwala YS, Zhang CA, Lu Y, Eisenberg ML. The age of fathers in the USA is rising: an analysis of 168 867 480 births from 1972 to 2015. Hum Reprod. 2017;32:2110–6.
3. Organisation for Economic Co-operation and Development. SF2.3: Age of mothers at childbirth and age-specific fertility. 29 May 2019. http://www.oecd.org/els/soc/SF_2_3_Age_mothers_childbirth.pdf. Accessed 22 October 2019.
4. The American College of Obstetricians and Gynecologists Committee on Gynecologic Practice and The Practice Committee of the American Society for Reproductive Medicine. Female age-related fertility decline. Committee Opinion No. 589. Fertil Steril. 2014;101:633–4.
5. Liu KE, Case A. No. 346—advanced reproductive age and fertility. J Obstet Gynaecol Can. 2017;39:685–95.