I Had A 5mm Cyst Surgically Removed From My Cervix

I had a 5mm cyst surgically removed from my cervix in Jan 2016. I fell pregnant in August 2016 and I am now currently 23weeks+4days pregnant.

I have had TVS scans at:
16 weeks my cervix length was measured to be 33mm
20 weeks my cervix length was measured to be 37mm
23 weeks my cervix length was measured to be 27mm

The sonographer said that I do not need any further appointments and to call my doctor if I have any bleeding, tightening of the stomach or cramping. This was the only information I received.

Would you recommend that I ask for a further scan at a later date? Is there anything I should avoid or not do to reduce risk of preterm birth/further shortening of the cervix? Do I have reason to be concerned?

Thank you for your help