According to Official Guinness Records,
The oldest mother is Maria del Carmen Bousada Lara (Spain, b. 5 January 1940), who gave birth by caesarean section to twin boys, Christian and Pau, aged 66 years 358 days at the Sant Pau hospital, Barcelona, Spain on 29 December 2006. Maria received IVF treatment in America (by lying that her age was 55 years), after being rejected for treatment in Spain. She is unmarried. Unfortunately, Maria passed away on Saturday 11 July 2009 after being diagnosed with cancer.
For a complete list of 2006 records, please visit 2006 Guinness Records in Spain.