It is therefore only possible to estimate the number of women exposed. However, DES was not routinely prescribed in the UK.The Medicines and Healthcare products Regulatory Agency (MHRA) uses the findings of a survey conducted by the Royal College of Obstetrics and Gynaecology (RCOG) which was published in 1974 and this suggested around 7,500 women in the UK were treated with DES during pregnancy in the interval 1940-1971, mostly during the 1950s.