my last pregnancy i gave birth at 24+2 due to cervical insufficiency that went undetected... so this pregnancy im having weekly scans to check cervical length... last week (14 weeks) it was 4.5cm which i was really pleased about.. then this week (15 weeks) it was 3.48cm.. they dont seem concerned as the said only if it gets to 2.5cm will they be concerned and il get a stitch... but to me that is a big difference in only 1 week? they said measurements can differ week to week and there is no funneling etc (does shortnening of cervix only happen with funneling or can it shorten without).. as any one had the scans that has any advice.. am i right to be concerned? absolutely any input welcome please 🤔🤔