Performing An Arom: What You Need To Know

Amniotomy, also known as artificial rupture of membranes (AROM) or breaking the water, is a procedure to induce labour or facilitate birth. It involves the intentional rupture of the amniotic sac, a pouch of fluid that surrounds and protects the baby, by an obstetrical provider. This procedure is typically performed by a midwife or obstetrician and has been used for at least a few hundred years. While it was once thought to be an effective means to induce or accelerate labour, its benefits and effectiveness are now debated.

Inducing labour

AROM involves rupturing the amniotic sac, which can be done using a specialised tool, such as an amnihook or amnicot, or by the proceduralist's finger. The amniotic sac is a dual-layer membrane that forms an enclosed space within the uterus, where the fetus develops and is protected.

Ensure that the mother meets the criteria for AROM:

• The mother should have no contraindications for vaginal delivery.
• The mother should be in labour or have an indication for delivery.
• The fetal head should be engaged (0 station or more).

Prepare the necessary equipment:

• Sterile gloves and lubricant
• Personal protective equipment (PPE): gloves, gown, drapes, mask, and eye protection
• Absorbent pads and towels to place under the patient
• Electronic fetal monitor (cardiotocography/CTG)
• Tocolytics
• AROM-Cot® finger cot (if using this method)

Assess cervical dilation and fetal presenting part:

• Perform a sterile digital exam to assess cervical dilation.
• Confirm that the fetal presenting part is the head and that it is well engaged in the pelvis.

Choose the appropriate tool:

• Amnihook: a sterile plastic hook that is inserted into the vagina to puncture the amniotic sac.
• Amnicot: a finger cot with a hook on the end that is placed on the finger, allowing for more precise hook application and reduced patient anxiety.

Perform the rupture:

• When using the amnihook, hold the end of the rod outside the vagina with the non-dominant hand and protect the hook end between two fingers when entering the vagina.
• Palpate the amniotic membrane and presenting part, then advance the hook to the membrane and gently tear it.
• Successful rupture is indicated by the immediate release of amniotic fluid, which is usually clear and odourless but may contain meconium or be blood-tinged.
• Do not immediately remove the hand from the vagina after rupture, as this is when the risk of cord prolapse is highest.

Monitor the mother and fetus:

• Note the colour of the amniotic fluid and document the findings.
• Monitor the mother's vital signs, including temperature, and watch for any signs of infection.
• Monitor the fetal heart rate via continuous electronic fetal monitoring.

Educate and support the mother:

• Explain the procedure to the mother and address any concerns.
• Minimise cervical exams after AROM to reduce the risk of infection.
• Perform regular temperature checks throughout labour.

Be mindful of potential complications:

• Prolonged rupture of membranes can increase the risk of infection.
• Umbilical cord prolapse may occur if the head is not engaged in the pelvis before rupture.
• There is a risk of intrapartum chorioamnionitis if AROM is performed too early in the labour process.

It is important to note that while AROM is commonly used to induce labour, there is limited evidence supporting its effectiveness. Some studies suggest that it does not shorten the length of the first stage of labour and may increase the rate of caesarean sections. Therefore, it is recommended to carefully assess each situation before performing AROM.

Monitoring baby's heartbeat

Monitoring a baby's heartbeat is a common test that healthcare providers use to check the health of the developing foetus during pregnancy and labour. There are two ways to monitor a baby's heartbeat: external and internal.

External Monitoring

External monitoring is performed on the outside of the abdomen. It can be done using manual or electronic devices:

• Fetoscope: This is similar to a stethoscope and is used to listen to the baby's heartbeat.
• Handheld Doppler ultrasound: This uses sound waves to measure the baby's heart rate. It is often used during prenatal visits, and a gel is applied to the abdomen before the probe.
• Continuous Doppler ultrasound: During labour and delivery, an elastic strap holds the ultrasound device in place on the abdomen. This provides a continuous readout of the baby's heart rate.

Internal Monitoring

Internal monitoring involves attaching a wire to the baby's head to track the heart rate continuously. This is done during labour and delivery, after the water has broken, and when external monitoring is unreliable or more precise monitoring is needed. A thin wire is threaded through the cervix and connected to a monitor.

Internal monitoring carries more risks than external monitoring, including injury to the baby's scalp and increased risk of HIV or genital herpes transmission from mother to baby.

Check colour of amniotic fluid

Checking the colour of amniotic fluid is an important part of prenatal care. Amniotic fluid is typically a clear liquid but can have different colour tints depending on the health of the foetus.

In the early stages of pregnancy, amniotic fluid is clear white. As the foetus grows, the colour of the amniotic fluid will become whiter and cloudier due to the presence of many substances, including fatty acids from the pregnant person's diet. By the 38th week, when the foetus is mature enough, the amniotic fluid will be milky white, similar to rice water.

Abnormal amniotic fluid colour can indicate potential health issues for the foetus. For example:

• Greenish-yellow amniotic fluid may suggest foetal hemolysis or intrauterine growth retardation.
• Dirty or green-mossy-coloured amniotic fluid, or fluid containing meconium (the baby's first stool), indicates that the foetus is severely weakened in the womb, which can be life-threatening.
• Cloudy green amniotic fluid that resembles pus and has a foul odour suggests an infection of the amniotic fluid, putting the baby at high risk of infection in the womb.
• Red-brown amniotic fluid indicates that the foetus may be stillborn.

The colour of amniotic fluid can be observed through amniocentesis when the cervix dilates larger than 1 cm or through the abdominal wall. Spontaneous rupture of membranes or amniotic fluid tamponade also allows for an accurate assessment of the colour.

Avoid baby aspirating amniotic sac

The amniotic sac, also known as the "bag of water", is a protective membrane that surrounds a fetus during pregnancy. It contains amniotic fluid, which is critical for fetal development, cushioning the fetus from bumps and helping to regulate its body temperature.

In some cases, the amniotic sac may need to be ruptured artificially, in a procedure known as amniotomy or artificial rupture of membranes (AROM). This is typically done to induce or speed up labor, or to facilitate the placement of internal fetal monitoring devices. However, one of the reasons for performing an AROM is to avoid the baby aspirating the contents of the amniotic sac at the moment of birth.

Most often, the amniotic sac will break on its own, usually by the beginning of the second stage of labor. If it remains intact, it will break with the mother's pushing efforts. However, in rare cases, the baby may be born with an intact amniotic sac, which must be quickly broken to allow the baby to breathe. This is because meconium, the baby's first poop, can sometimes be passed during labor and delivery, putting the baby at risk of aspirating the sticky substance and causing breathing problems and respiratory distress.

To avoid this, healthcare providers will monitor the amniotic fluid for meconium and watch for fetal distress. If meconium is detected, the baby's airways will be suctioned as soon as the head can be seen during delivery, to prevent severe aspiration.

Speed up labour

How to Perform AROM to Speed Up Labour

AROM, or Artificial Rupture of Membranes, is a procedure that can be performed to speed up labour. It involves manually breaking the amniotic sac, also known as "breaking the water", to stimulate contractions and shorten the length of labour.

AROM is typically performed to speed up or induce labour, or to kick-start stalled labour. It is also done to allow for internal monitoring of the baby or to check the colour of the amniotic fluid (liquor) if there are signs of distress.

If labour hasn't started, a speculum may be placed into the vagina to visualise the amniotic sac. If active labour is ongoing, a practitioner may use their fingers to feel for the sac. A small hole is then punctured in the sac using an "amnihook", which resembles a crochet hook.

What to Expect During AROM

You may experience some cramping or discomfort during the procedure, but the actual rupture of the amniotic sac is usually painless. Once the sac is punctured, you may feel a gush of water or a trickle of amniotic fluid.

Benefits and Risks of AROM

AROM can lead to a significant increase in the intensity of contractions, which can be beneficial for speeding up labour. However, there are also risks associated with the procedure, including:

• Prolapsed cord, where the umbilical cord slips past the baby's head, requiring an emergency C-section
• Increased risk of infection, especially if labour progresses beyond 24 hours after the water is broken
• Difficulty in un-squishing the umbilical cord or placenta if it is causing a drop in the baby's heart rate
• Increased need for pain management or an epidural due to the intensity of sensations

Frequently asked questions