Monday, October 1, 2012

Obstetrics - Is it PROM, PPROM, or What?

A common point of confusion is what exactly PROM and PPROM mean when talking about a baby being born. When the acronyms are used, there is often some minor doubt as to what exactly we are referring to. There are a few basic concepts here that are straightforward but also important to the health of the baby.

Here are the main concepts:

-What is "rupture of membranes?": The mother's body generally determines when it is time to push out the baby. It does this by having the womb/uterus start to clench (this is what we call Labor) to push the baby out the vagina into the world. When the uterus clenches, it breaks the bag of water inside the uterus (my water broke!) that the baby has been floating in for 9 months. The bag itself is made of two layers which are the membranes that have to break for the water to flow out (the baby isn't going to fit out the vagina if the bag of water is still full). So breaking the water bag that the baby is floating inside = Rupture of Membranes (ROM). So ideally mom's body decides it's time to expel the baby, it starts squeezing, the bag of water protecting the baby breaks, and then some time later the baby is pushed out the vagina. However, it does not always work this way.

-Why do we care about membranes rupturing? The main reason we care is that for it's entire growth in the womb, the baby is immersed in this fluid filled sack. This sack is what protects the baby from bacteria which can cause infection. If the sack wasn't there, bacteria and viruses from places like the vagina could enter the womb and infect the baby. The sack is a barrier for this happening (not perfect, but still very important). So when the sack breaks, the baby loses it's defense barrier. Also, around this time the womb is starting to open up the passage to the vagina to get ready to start pushing the baby out. When the passage starts opening, it creates a direct path for bacteria from the vagina to go into the womb and infect the baby. So having the sack intact, is very important to the baby not getting an infection.

-What is Premature Rupture of Membranes?: So normally the bag of fluid only breaks after it has been squeezed a bit by the uterus during contractions. Sometimes though the bag will break on its own without the uterus making it happen. If the baby is old enough, this doesn't mean that the delivery will not go well, but it does beg the question, "why did this happen?" The main thing we worry about is infection. An infection involving the baby or mother can trigger the water breakage. So if the water breaks without the uterus breaking it itself, you gotta be sure there's no infection going on. Because this is a concerning event, the term Premature Rupture of Membranes is used to emphasize that this is an important event.

Literal Definition:

Premature Rupture of Membranes (PROM) = fluid sack breaks before labor (i.e. the sack breaks on its own with no help from the squeezing of uterus)


-What is PPROM?: this stands for Pre-Term, Premature Rupture of Membranes. This is basically the same thing as PROM except when it happens to a baby less than 37 weeks along. The distinction is made because since the fetus is not old enough to truly be ready to come out, there is a greater risk for problems for the baby once it's been born. 

-What is Prolonged Rupture of Membranes?: this term goes back to the sack being a protective barrier for the baby against infection. It doesn't necessarily have anything to do with PROM either. It just means that there was a longer time between the time the sack breaks and when the baby was fully delivered than is hoped for. This is usually considered more than 1 day. So the baby has had a longer time hanging out in the womb without the protection of the sack so has had more time possibly exposed to bacteria which can cause infections. People often confuse this term with Premature Rupture of Membranes because the acronym would be the same. The key is to remember that there is no acronym for Prolonged Rupture of Membranes. PROM never equals prolonged rupture of membranes.

To review the three terms:
  • PROM: Premature Rupture of Membranes (sack breaks before labor/contractions start; be worried about infection)
  • PPROM: Preterm PROM (same as PROM except when baby is younger than 37 weeks; alerts doctors that there is a higher health risk for the baby since it is not fully developed yet)
  • Prolonged Rupture of Membranes: NO ACRONYM! The time from when the baby loses the sack as an infection barrier to the time the baby is born was long (>1 day; greater time exposed to bacteria in the mother so greater risk of having an infection)

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