What's Funneling in Pregnancy?

Cervical funneling is defined sonographically as a protrusion of amniotic membranes into the internal cervical os by greater than 5 mm from the shoulder of the original internal os as measured along the lateral border of the funnel [4]. This finding is usually accompanied by short cervical length (defined as <25 mm).

What causes funneling in pregnancy?

The main causes of a short cervix and cervical funneling include heredity, trauma, abnormalities of the cervix or uterus, or having an insufficient cervix (also called incompetent cervix). An insufficient cervix is when your cervix opens or dilates too early and is a common cause of premature birth.

Is cervical funneling normal?

Cervical funnelling is a sign of cervical incompetence and represents the dilatation of the internal part of the cervical canal and reduction of the cervical length. Greater than 50% funnelling before 25 weeks is associated with ~80% risk of preterm delivery.