black and white photo of mother holding newborn baby on her chest moments after birth

Amniotic fluid AKA “waters” surround and cushion your baby. It is a protective fluid that consists of nutrients, like electrolytes, carbs, proteins, lipids, etc. Your baby swallows and “breaths” it into their lungs and it is absorbed into their skin. It aids in your baby’s development. It is incredible stuff!

The waters are inside 2 membranes. The inner membrane is called the amniotic membrane and the outer membrane is called the chorionic membrane. You may have heard this structure called “the amniotic sac” or “bag of waters”. The membranes are very strong. They hold the weight of your baby and amniotic fluid, and are resilient against your baby’s flips, kicks, punches and somersaults.

Over time as you approach your baby’s birth day a small area of your membranes start to weaken, typically near your cervix. Eventually the membranes break just before or during labour. When this happens on its own, it is called spontaneous rupture of membranes (SROM).

When your “water breaks” spontaneously

When your bag of waters rupture, the hormone Prostaglandin is released. Prostaglandins work hand in hand with the hormone Oxytocin to trigger contractions. However, it’s not like the movies, where everyone’s labour seems to start with a gush of waters, that is not common.

Only about 8 – 10% of people start their labour with their waters breaking. For most, their waters do not release until later in their labour. For a rare few (1 in 80,000 births), the waters do not release and their baby is born in their bag of waters. The term for this is type of birth is being born “en caul” and it’s pretty cool.

During labour if the waters are still intact they help to protect the baby from different bacteria infections (one type is GBS). The waters also cushion your baby’s body making labour less painful for you, and it protects your baby’s umbilical cord from being squeezed too tightly during contractions.

So, what is artificial rupture of membranes (AROM) AKA amniotomy?

AROM is when your healthcare provider breaks the membranes for you. Your OB or midwife will insert two of their fingers into your vagina to guide an AmniHook® (which looks like a crotchet hook) inside your cervix to rupture the membranes. This doesn’t hurt you or the baby. The procedure is uncomfortable in the same way that having a cervical check is, but the hook itself and the release of waters does not hurt. The procedure can be done at home births, birth centres or in the hospital.

Why would your healthcare provider want to rupture your membranes?

  1. Healthcare provider preference – it could be how they routinely manage every birth, even a low risk normal labour.
  2. To speed up labour – however, the evidence on this working is weak and there are concerns around whether the benefits outweigh the risks.
  3. Used to induce or augment labour – if labour has not started on its own or labour slows/stops, often AROM is used to help labour start (“induce”) or progress (“augment”). AROM can also help to make contractions from the IV medication Pitocin (synthetic Oxytocin) more effective. There is conflicting research on this topic and concerns around whether the benefits outweigh the risks.
  4. To help resolve or confirm concerns about baby’s well being. If your baby shows signs of distress during labour, AROM may help your healthcare provider to monitor your baby’s heart rate internally, to see if baby has had their first bowel movement (“meconium”), to aid in assisted vaginal delivery with the use of forceps or vacuum vaginal delivery.

AROM is a very polarizing topic

Some healthcare providers routinely rupture the membranes and some do not unless absolutely medically necessary. Many fall somewhere in the middle making decisions based on each individual birth. Where does this leave you in making a decision around AROM?

This doula’s two cents

There is no one perfect, blanket answer. The most important aspect to making decisions in labour is informed consent and open communication with your healthcare provider.

You should ask:

  • Why is this procedure being recommended?
  • Is it medically necessary?
  • What are the risks and benefits?
  • Is it urgent or can this intervention wait?

It is important to know while one-sized, routine interventions aren’t recommended, the appropriate use of interventions might actually help you achieve your birth wishes. For example, I myself had 3 babies, one SROM and two AROM. For me, AROM was necessary both times. The first was to help aid in the vaginal delivery of my breech baby, and the other was to determine why my baby was having a low heart rate and whether we needed to move from a homebirth to a hospital birth. In the end I was able to have my homebirth! It’s also important to know in my case, AROM was done when I was past 8cm dilated and after careful consideration of the risks and benefits.

Final thoughts

Interventions are not inherently evil, but you need to be involved in the decision making if you want to have a safe and more satisfying birth experience. Don’t be afraid to do the research. Engage with your healthcare provider, put your wishes into a birth preferences document and then be prepared to be flexible if a medical need arises.


Sarah Baker is a the co-owner of Lifetime of Love Doula Services and has been supporting families for almost a decade as a birth doula, postpartum & infant care doula and childbirth educator.  She is mom to three boys, twins and a singleton.

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