Research shows that cervical screening is declining across the UK with more than one in three young women failing to attend smear tests, according to a new review.
A total of 37% of women aged 25 to 29 missed out on a test in 2014.
This is despite more than half (52%) of cervical cancer cases in the UK each year occurring in women aged under 45.
The new review, published in the Obstetrician and Gynaecologist journal, found screening rates have fallen among by 3.1% between 2004/5 and 2014/15, to 77.2%.
Overall, one in five women between the ages of 25 and 64, and one in three aged below 35, miss out on screening.
In England and Northern Ireland, women between the ages of 25 and 64 are invited for screening, with those aged 25 to 49 screened every three years and those aged 50 to 64 women screened every five years.
In Scotland, screening is routinely offered every three years to women aged between 20 and 60. In Wales, women between 20 and 64 are screened every three years.
There have been calls to lower the age at which women first start being screened following the deaths of some young women, including reality TV star Jade Goody, in 2009 at the age of 27.
But the Government in England has rejected this, saying lowering the age could cause too many false positive results, leading to unnecessary and potentially harmful treatment.
Dr Theresa Freeman-Wang, consultant gynaecologist and co-author of the new study, said it was "incredibly worrying" that so many women are missing out on cervical screening.
She said young women may believe they are totally protected against cervical cancer if they have received the human papilloma virus (HPV) jab, which projects against several strains of disease that cause the cancer.
But she said: "Although the vaccine is effective against the two most common strains of HPV which cause around 70% of cervical cancers, it doesn't prevent all of them, so it's essential they go for cervical screening from the age of 25.
"Research shows that inconvenience, a fear of cancer and concerns about the procedure put women off from making an appointment. Ensuring that coverage does not decline any further remains an important public health issue."
Just over 3,000 new cases of cervical cancer are diagnosed each year in the UK and there are over 900 deaths.