The Membranes


To me, the amniotic membranes are an amazing and beautiful thing. They embody the concept of strength in flexibility. Being so incredibly thin and yet such a tough defender of the babe. Keeping the baby tucked inside; encompassing the salty, warm, nurturing environment of the womb. When I do vaginal exams (you can read more about my philosophy of vaginal exams here) during labor, and I feel that filmy, slippery membrane I am constantly in awe of its power. The veil at the doorway that separates our two worlds.

For some laboring people, the membranes release on their own, either before the onset of labor or during. For other laboring people the membranes do not release until at the time of, or shortly after, birth.  And for some, the membranes are artificially ruptured by a provider. Fun side note, I have seen a powerful laboring person reach inside themselves and rupture their own membranes!

This post will break down all the various ways waters can break and how this can be handled. But first, let’s take a moment to acknowledge when the membranes do not release. This is called being born ‘en caul’ and across cultures is considered to be a blessing for the baby, the family and even the community.

the membranes

The Membranes: An En Caul birth Story

The laboring person was sitting on the birth stool with a bulging bag of waters crowning. Through the bag and the waters, I can see specks of vernix floating in the clear fluid. I can also see lovely dark hairs dancing and swirling, suspended in the waters, moving in tune with the labor song and the birth rushes. For a moment, I am transfixed by the beauty, floating in the space between connected to the babe and the laboring person on some astral level. Then with a grand grunt, I am pulled back and place my hand near the babe’s head, expecting the bag to break and flood me with a wave, but it doesn’t budge. Instead, the babe is birthed, bag and all, into my hands. The image will remain with me always, the alert eyes of the baby looking up through the membranes and fluid, ready to join the world. (This particular birthing person, did not want to catch their baby and was also someone who needed a moment to catch their breath in those few seconds immediately after the birth. This is not unusual and in these situations I feel honored to be the temporary bridge between the two worlds.) So, with this dark haired, clear eyed baby looking up to me, I gently pulled the membranes open. The waters released, the babe cried and their parent reached down for them with pure joy.

All right, after that little oxytocin inducing story, lets get down to some definitions!

  • Preterm Prelabor (or Premature) Rupture of Membranes or PPROM. This is when the waters release before the baby has reached 37 weeks gestation. Depending on how premature the baby is, labor may be induced or delayed. It becomes and assessment of the risk versus the benefit of more time in the womb to develop versus the chance for infection. Steroids may be recommended to help the fetal lungs mature and antibiotics may be considered to decrease the risk for infection.
  • Prelabor (or Premature) Rupture of Membranes or PROM. This is when the waters release when the baby is full term, past 37 weeks, but labor has not yet begun. This occurs in approximately 8-10% or pregnancies. Although, I often joke that it happens all the time in movies and the TV because it can made into a dramatic moment after which comedy can ensue. When this happens, the good news is that 95% of people will spontaneously start labor on their own within 24 hours.
  • Spontaneous Rupture of Membranes or SROM. This is when the waters release after the onset of labor. It can happen in the first stage, either latent or active. Or during second stage with pushing. Mainly, it means that there have been regular contractions prior to the rupture.
  • Artificial Rupture of Membranes or AROM. This is when a provider preforms an intervention to artificially rupture the membranes. This is usually done with an instrument called an amniohook. These tools like like a flattened crotchet hook. The provider does a vaginal exam, with the examining fingers inside the cervix, the amniohook is held in the other hand, inserted into the vagina through the cervix and used to “hook” the membranes to release them. This is not a risk free intervention and should be thoroughly discussed and reviewed, through Shared Decision making between the provider and client prior to preforming.

So, let’s down to business. What do you do if you think your waters have broken?

To clarify, for some people it is very obvious that the waters have released, it is a dramatic movie worthy moment of lots and lots of fluid. For others, it can be more subtle and less dramatic. One of the first things to do, if you have any inkling or thought your waters released, is to call your provider. Depending on your personal history, pregnancy history and plan for birth your provider may want to see right away or they may have you remain at home for some time. Either way, they should be informed of your situation and involved in the plan. When you speak with them, there is a standard set of questions likely to be asked. These are referred to as “TACO” or “COAT”. (Clearly TACO is more fun!)

  • T- Time; when did the fluid start leaking? Hopefully, this will be relatively close to when you are calling. Please don’t wait hours or days to call.
  • A- Amount; how much fluid is leaking? Was it big and dramatic or is it a steady slow leaking? Also, FYI, once your water breaks you will continue to leak until the baby is born, so be prepared for that.
  • C- Color; what color is the fluid? Is it clear, yellow, green or brown? It can also be slightly pink tinged if you are also having some bloody show. Optimally, it should be clear.
  • O- Odor; does the fluid have a foul odor? Amniotic fluid has an inherent odor, to me, it smells “earthy or musky” and slightly sweet. After over a decade attending births, I can often smell it from across the room but it is generally a subtle aroma. You do not need to put your nose in it and inhale! If you don’t notice a foul odor from just cleaning it up then that is good.

How is Rupture of Membranes confirmed?

First, often it is easy to determine visually if there is a lot of fluid. This is called “grossly ruptured” (gross refers to the amount, and is not a judgement of the fluid itself). If visual confirmation is not possible or seems questionable, then some tests will be done to determine if there is amniotic fluid present and leaking. ****Important side note: in the case of PPROM or PROM, it is critical to NOT have a cervical exam without a very good reason! The first time a cervical exam is done, starts the clock on an infection setting in. And in general, cervical exams should be limited to as few as possible**** Traditionally, this is done through an examination called a Sterile Speculum Exam or SSE. A SSE is different from a cervical exam because, no instruments, fingers or tools are passed through the cervix itself. And, as the name implies, all sterile tools should be utilized. Four things are looked for with a SSE:

  • Pooling: when the sterile speculum is placed in the vagina, the provider looks for the presence of a “pool” of fluid in the posterior portion of the vagina.
  • Valsalva: the pregnant person is asked to cough or mildly bear down to see if fluid can be visualized leaking form the cervical opening.
  • Ferning and Nitrazine: if there is fluid present, sterile cotton swabs will be used to obtain a sample of that fluid. I usually gather two at the same time, so that I can use one a piece of nitrazine paper and use the other to transfer the fluid to a microscope slide.
  • Here is a super cool tidbit! Amniotic fluid is high in sodium chloride, a type of salt, some say it is very close to the salinity content of ocean water. So when it dries those salt crystals create a very distinctive crystalline pattern that closely resembles the leaves of fern plants. (so many lovely connections to our natural world) After applying any fluid to a microscope slide, it is allowed to dry and then looked at on the microscope.
the membranes, ferning
Ferning on microscope
  • The normal pH of the vaginal secretions is mildly acidic at 4.5-6.0. Amniotic fluid is more alkaline at 7.1-7.3. Nitrazine paper can be used to test the pH of the fluid. In the presence of amniotic fluid the paper will turn a deep, indigo blue. Other fluids, such as blood and semen, can also turn the paper a green-blue so care should be taken to rule out these factors.
the membranes, nitrazine paper
Nitrazine paper positive for amniotic fluid

Nowadays, there are also commercial tests available to determine if the waters have released. These can be beneficial because they do not require a speculum exam. They can also be expensive, difficult to store and have set expiration dates. One of these is called ROM Plus and another is called AmniSure. There are apparently also menstrual like pads that have a pH substance in them that will turn blue when exposed to amniotic fluid, however, I have never used these or actually seen them and cannot find them online. If you have a source, please share in the comments.

Your waters have released now what?

The answer to this question, as mentioned above will vary depending on your individual situation and full clinical picture. Some major factors to consider are: the color of the fluid, your Group Beta Strep (GBS) status and overall fetal well being. For example, fluid that is not clear can be related to meconium, or baby poop in the waters. Sometimes, there can be meconium released by the baby in response to a stressor. Or it may simply mean that your baby is mature and has naturally released meconium. Your provider should discuss these factors with you.

A very thorough Informed Consent and Shared Decision Making conversation should be had with your provider to determine the next best steps. Common choices are expectant management (fancy for watchful waiting) or induction of labor. Risks, Benefits and Alternatives of all possible interventions should be laid and all of your questions should be answered clearly. Generally speaking, PROM is not an emergency and you should be given time to make choices. An excellent resource for learning even more can be found on the amazing Evidence Based Birth website. This is an invaluable source of all kinds of great information.

What type of membrane release did you experience? How was it handled? Did you feel well educated and supported?

Images credit to Aubre Tompkins, CNM

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