Cutting through the amnion in order to release amniotic fluid. With reduction in pressure release and of balloon release effect, the baby's head descends and labor progresses. Release of amniotic fluid also shortens the muscle bundles of the myometrium thereby increasing the strength and duration of contractions. It is  a method used to accelerate or induce labor. It is best performed in active phase labor but however increases the risk of early and variable dips.