In amniotomy, the physician or nurse-midwife uses a sterile amniohook to rupture the amniotic membranes. This procedure prompts amniotic fluid drainage, which enhances the intensity, frequency, and duration of uterine contractions by reducing uterine volume.

Amniotomy is performed to induce or augment labor when the membranes fail to rupture spontaneously. It helps to expedite labor after dilation begins, and facilitates insertion of an intrauterine catheter and a spiral electrode for direct fetal monitoring.

Oxytocin infusion may precede amniotomy or follow it by 6 to 8 hours if labor fails to progress. If birth doesn’t occur within 24 hours after amniotomy, the physician may decide to perform a cesarean delivery to reduce the risk of infection.

When deciding whether to perform amniotomy, the physician or nurse-midwife considers such factors as fetal presentation, position, and station; the degree of cervical dilation and effacement; contraction frequency and intensity; the fetus’s gestational age; existing complications; and maternal and fetal vital signs.

Amniotomy is contraindicated in high-risk pregnancies, unless more accurate fetal assessment using internal fetal monitoring is necessary. It’s also contraindicated when the presenting fetal part is unengaged because of the risk of transverse lie and umbilical cord prolapse.

Povidone-iodine solution

Linen-saver pads

Bedpan

Soap and water

External electronic fetal monitoring equipment or a fetoscope or Doppler stethoscope

Sterile gloves