The match, played earlier in March, was even for the first 15 minutes with a lot of rugby played in the centre of the field.
It took until the 24th minute for Maddie Poulter to break the deadlock with a try.
The score was followed on 29 minutes by a flowing move across the pitch which was finished off by Olivia Hawthorn.
Worcester piled on more pressure and on half-time Charley Campbell’s try gave them a 15-0 lead.
The second period started much like the first with both teams battling hard until Worcester broke from the halfway line to dot down under the posts.
The girls then defended bravely with big tackles before Peterborough eventually earned a consolation score with 10 minutes to go.
But the national semi-finals have been cancelled with the RFU ruling out any more rugby this season below the Premiership due to the coronavirus crisis.