1. Hamilton, B. E., Martin, J. A., Osterman, M. J. K., Curtin, S. C. & Mathews, T. J. Births:Final Data for 2014. National Vital Statistics Report 64 (2014).
2. ONS. Birth Summary Tables, England and Wales, 2013. Office for National Statistics (2014).
3. Canterino, J. C., Ananth, C. V., Smulian, J., Harrigan, J. T. & Vintzileos, A. M. Maternal age and risk of fetal death in singleton gestations: USA, 1995–2000. The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstet 15, 193–197, doi:10.1080 (2004).
4. Carolan, M. & Frankowska, D. Advanced maternal age and adverse perinatal outcome: a review of the evidence. Midwifery 27, 793–801, doi:10.1016 (2011).
5. Ludford, I., Scheil, W., Tucker, G. & Grivell, R. Pregnancy outcomes for nulliparous women of advanced maternal age in South Australia, 1998-2008. Australian & New Zealand Journal of Obstetrics & Gynaecology 52, 235–241 (2012).