Dynamic cervix

Has anyone been told they have a dynamic cervix? Went for our anatomy scan at 21w1d and they saw my cervix shortening and closing constantly. At shortest it was 2.8 and longest about 4. Curious if anyone has had this? Or even a cervix of 2.8 that didn’t get intervention (they told me they start worrying at 2.5 but 2.8 seems close to me!)

I’m a bit worried. I’ve had two miscarriages (though weeks 8 and 11) and this pregnancy is through IVF. It’s just been a long road. Any help or insight is appreciated!