Talk to Gynecologist on Cervical Length

Aoa. I am 22 weeks Pregnant. I got my anomaly scan done yesterday, everything was fine but I am bit concerned about my cervical length which is 3.0 Cms. Last time I Got my scan done at my 17th week it was 3.9 cm. and that time my baby was in Breech position and now the baby is in Cephalic position. I am so concerned about this decreasing cervical length. I want to ask if the cervical Length changes with baby’s position ? And is there anything to worry about ? My doctor is on leave and she’ll be available on 11th April. If someone can guide.