Amniotomy does not hurt or cause pain to the mother or the baby. The mother may experience a little discomfort when the amniotic hook (the instrument to perform amniotomy) is passed through the birth canal. Amniotomy is typically followed by increased contractions to facilitate labor. The doctor may often rupture the amniotic sac to get the labor started. This procedure is called an amniotomy and requires the doctor to make a small hole in the amniotic sac with a special tool called an amniotomy hook. The doctor may also do the same procedure if the patient is in labor, but the amniotic sac is not broken yet.
- An amniotomy is performed by an obstetrician in a labor or delivery room, with the patient lying on a hospital bed. In some cases, the patient is asked to stay in a semi-sitting position to minimize cord compression and ensure a good oxygen supply for the fetus.
- The procedure is done when the neck of the womb (cervix) is thin and dilated, and the head of the baby has moved down into the pelvis (engaged).
- The procedure is done using either an amniotic membrane perforator, also known as an amniotomy hook or AmniHook or an amniotic finger cot.
- Before performing the procedure, it is crucial to determine the fetus’s presentation and location. Second, the patient may need to be placed on an electronic fetal monitor to monitor fetal wellbeing.
- When the patient has been prepped for the procedure, the obstetrician proceeds to dilate the opening of the womb.
- The doctor then ruptures the amniotic membrane using the hook, timing it in between contractions. As the amniotic fluid begins to flow out, the doctor keeps one hand in the vagina to let it flow in a gradual manner and prevent umbilical cord prolapse.
- As a follow-up step, the doctor measures and notes the color, odor, volume, and consistency of the fluid that comes out.
- After an amniotomy, the fetus’ heartbeat will be assessed for one full minute, which is also performed prior to the procedure. This is to check for any changes in the fetus’ condition and any warning signs that may signal fetal distress.
There are certain complications associated with an amniotomy. These include:
Cord compression: Baby’s umbilical cord becomes compressed or flattened, usually because of the movement of amniotic fluid as it is released. When this occurs, the fetus may not get enough oxygen and blood, and this, in turn, places the baby at risk of heart problems and birth injuries. If mild cord compression is suspected, the patient may simply be given additional oxygen or asked to change position to relieve the compression. However, if these do not work and the fetal heart rate changes drastically, the patient may need an emergency cesarean delivery.
- Cord prolapse: It refers to the situation when the umbilical cord drops between the part of the fetus near the birth canal (the presenting part) and the cervix into the vagina. This commonly occurs because of the sudden and rapid flow of amniotic fluid, which is why the doctor has to control the flow once the sac has been ruptured.
- Fetal blood loss: This can be a life-threatening complication, one that warrants an emergency cesarean delivery to save the fetus.
- Fetal scalp trauma: If the head of the fetus is positioned too closely to the amniotic membrane, it may be possible for some scalp accident or injury to occur, but this is often very mild.
- Infection: The pregnant patient may need to be given antibiotics because once the amniotic fluid is released, there is a high risk of intrauterine infection.
- Chorioamnionitis: This refers to the infection of the fetal membranes.
Why is amniotomy done?
Amniotomy is done to: