This is the artificial rupture of membranes. It is supposedly done to "speed up" labor, though most studies say that this is not true for most women. 75% of the time your water will break past nine centimeters. Amniotomy may also be used to assess if the baby has passed meconium or to allow the insertion of internal fetal monitoring.

It is done by placing a amniohook (looks very similar to a long crochet hook) inside the vagina during a vaginal exam and scratching the bag until it ruptures.

Drawbacks to this can include:

• Increased risk of infection
• Lack of cushion for the baby's head
• Increased intervention, and limited mobility

There are other ways to speed labor, including walking, nipple stimulation, position changes, etc.

Amniotomy may also be used as an induction technique.

_{Source:
Fraser WD, Turcot L, Krauss I, Brisson-Carrol G. Amniotomy for shortening spontaneous labour. Cochrane Database of Systematic Reviews 1996, Issue 2. Art. No.: CD000015. DOI: 10.1002/14651858.CD000015.pub2}