ARM can be performed to induce labour once the cervix is favourable (Bishop's Score >5). It can also be used to augment labour if there is slow progress and membranes have not ruptured spontaneously.
Before beginning ensure that the head is well applied to the cervix (on vaginal examination) and continuous CTG monitoring is available if indicated.
Once the tips of index and middle fingers are in contact with membranes, and amniotomy hook is passed along the groove between two fingers (hook pointing inwards) and the hook is then pointed upwards to rupture membranes. Ensure cord has not prolapsed before removing fingers and monitor fetal condition on CTG.
Liquor is usually seen after ARM. Absence of liquor following ARM could be because of a well-engaged head or oligohydroamnios. Monitor the fetus carefully if liquor is absent.
Cord prolapse is a dangerous complication of ARM, so ensure the head is well engaged before rupturing membranes.
90% of mothers labour spontaneously following ARM.