Women are facing a 10-week delay to receive results of their smear tests.
Thousands of women in the West Midlands are thought to be affected by the backlog that built up after Royal Wolverhampton NHS Trust took over the service.
It said it hoped to meet the national target to return results within two weeks by the end of February.
Paris Jones, who waited two months for results to show she had pre-cancerous cells, said it had been “stressful”.
The trust, which took over the service for Stoke-on-Trent, Birmingham, Coventry, Herefordshire and Worcestershire in April 2019, said it had transferred laboratory screening services from five existing providers to a newly built facility on the New Cross Hospital site.
The type of screening provided also changed and some of those who had previously provided the tests handed over services earlier than expected, which meant women now faced a 12-week wait to receive results.
A spokesperson for the trust said it was “aware of the impact of the delays”.
“The trust is working closely with NHS England and Improvement and is making good progress,” they added.
Nationally, there have been problems with delays in cervical screening results, with targets not being met since 2015.
Ms Jones, 25, a midwife from Birmingham, had her first smear test in June and had to wait “about eight to 10 weeks” for her results, which showed abnormalities.
She subsequently discovered she had pre-cancerous cells at a colposcopy, and had them removed in a procedure in January.
“Most people think if you haven’t heard anything it is normally fine, but I think if you were to wait 12 weeks to then find out something was wrong you would be a bit irritated,” she said.
Tracie Miles, specialist nurse for gynaecological cancer research charity The Eve Appeal, said the delay was unlikely to have a clinical impact.
“On balance, the biggest thing is anxiety, it may cause a women to put off her next test and think ‘I don’t want to go next time, it is too worrying’,” she said.
NHS England said: “Local areas are working hard to minimise any delays to results, which are expected to be back on track shortly.”
Follow BBC West Midlands on Facebook, on Twitter, and sign up for local news updates direct to your phone.