Amniotomy or “breaking the water” can be done by the midwife using a small plastic device called an amnihook. It is not a painful procedure. It requires a vaginal exam which may be uncomfortable. The small hooked end of the amnihook makes a small tear in the amniotic sac. This does not hurt the laboring person or the baby.
It is sometimes done to see the color of the amniotic fluid, (the fluid should be clear, and green/black-colored fluid may indicate fetal distress) or to induce or augment labor.
Contractions often increase in frequency and intensity following amniotomy and possibly shorten labor. Once the membranes have ruptured, either spontaneously or by amniotomy, delivery should ideally be accomplished within 24 hours to reduce the chance of infection.