1. CBS.Statline.2015.http://statline.cbs.nl/Statweb/publication/?DM=SLNL&PA=37520&D1=0‐5 10 15‐19&D2=36&D3=a&HDR=T&STB=G1 G2&VW=T. Accessed April 19 2016.
2. Statistiek Cb.Vrouwen steeds later moeder.2018.https://www.cbs.nl/nl‐nl/nieuws/2018/05/vrouwen‐steeds‐later‐moeder. Accessed October 12 2018.
3. Reasons for delaying childbearing – a survey of women aged over 35 years seeking assisted reproductive technology;Hammarberg K;Aust Fam Physician,2005
4. Delayed Child-Bearing
5. Pregnancy in the Sixth Decade of Life