How often is meconium present?

[Maggirayne]

And how often do babies who have meconium in the waters actually in distress?
What do the different colours show? I don't know where to look, and I'm curious.

Thanks!

[MsBlack]

Once long ago...too long to remember where I saw this...I read that mec might be present in about 1 in 6 labors. I have not seen this in practice--more like 1 in 20 or fewer. Perhaps hospital protocols tend to cause more mec than homebirth does--I don't know. However, when I have seen mec, only twice did I also see fetal distress. One baby was stillborn; the mec was an effect of some other cause (never determined) and we stopped hearing his heart some minutes prior to birth, he never tried to breathe. One was born vigorous and never had any issues even tho the fluid was pea soup, very thick mec. One of my own babies had thick mec in the water, but also was fine.

Color can vary from light yellow/yellow-green to any shade up to dark green (pea soup) from what I've seen. It can be minimal and more like flakes distributed in mainly clear waters, it can be a large amount that entirely colors the waters, and anything in between. Rule of thumb is that pea soup is a cause for concern--some mws will transfer care if they see it, others will at least be ready for resuscitation including deep suctioning. Even though it doesn't always signify problems, thick mec is the sort that *can* cause the worst issues w/baby's lungs.

If you google meconium aspiration syndrome, you will find a lot of refs.

[MsBlack]

wanted to add--in the presence of mec, esp pea soup, most mws will also monitor baby's heart more often and more carefully to see if baby is in distress.

[mwherbs]

here is an abstract that give an idea so mec was present in 7.9% of all their births of that out of that number 3.4% developed respiratory symptoms
consistent with MAS and a little less than half of them were put on vent.
the numbers look like this:
7.9% (708 of 8,967) had Meconium present during birth
MAS symptoms- 24 infants
on vent with MAS 11 infants

something that this doesn't talk about is term/preterm and postterm births
I have read in other studies that Mec and preterm/early term is a greater risk than mec and postterm-- overall we are looking at fairly small numbers


Am J Perinatol. 2002 Oct;19(7):367-78.

Delivery room risk factors for meconium aspiration syndrome.

Liu WF, Harrington T.

Associates in Neonatology, HealthPark Medical Center, The Childrens Hospital of Southwest Florida, Lee Memorial Health Systems, Fort Myers, Florida 33908, USA.

The objective of this study is to identify risk factors for meconium aspiration
syndrome (MAS) in newborns born through meconium-stained amniotic fluid (MSAF). From May 27, 1994 to June 9, 1997 maternal and neonatal data were prospectively collected on all infants born through MSAF. Development of MAS was the primary outcome. Using bivariate and logistic regression analysis we identified risk factors for MAS. There were 8,967 births during this period: 7.9% (708 of 8,967) were delivered through MSAF. Respiratory symptoms developed in 6.8% (48 of 708) of births. Of these, 50% (24 of 48) were excluded due to the diagnosis of transient tachypnea of the newborn (17), respiratory distress syndrome (4), group B streptococcus pneumonia (1), congenital cytomegalic inclusion disease (1), and supraventricular tachycardia (1). Of the 24 infants with respiratory symptoms
consistent with MAS, 45.8% (11 of 24) required ventilatory support, one required extracorporeal-membrane oxygenation. Bivariate analysis identified six risk factors ( p <0.05): Apgar <7 at 1 minute, Apgar <7 at 5 minutes, thick meconium, fetal distress, suction of infant's stomach by delivery room team at <5 minutes of age, and need for resuscitation. Tracheal meconium was very prevalent in our population at 74% of all intubated infants, and was not significantly associated with MAS. Logistic regression analysis identified four independent risk factors. Looking at multiple prediction models, an infant with fetal distress, Apgar <7 at 1 and 5 minutes and thick meconium has a 79.8% probability of developing respiratory symptoms. If these risk factors are not present, there is a 0.8% risk. In our cohort, this group had 16.7% positive predictive value (4 of 24) and 99.6% negative predictive value (657 of 660). In meconium deliveries, infants with thick meconium, fetal distress, and Apgar scores <7 at 1 and 5 minutes are at high risk for development of respiratory symptoms. Infants delivered in the
absence of all of these risk factors are at low risk for development of MAS.


PMID: 12442226 [PubMed - indexed for MEDLINE]

[Malga]

mwherbs~ I see about 1 in 15 cases of it where I work right now in an OB unit and more like 1 in 20 when I attend OOH births. This could be also because we accept higher risk women at the hospital. Just had someone with moderate mec the other day-- mom was a heavy smoker-- baby had to be resus.

[Maggirayne]

Hmm, how often do you see faint meconium and does it mean anything?
That's the reason my docotr gave for breaking my water and there was a slight greenish tinge to my fluid. So did that 'mean' anything, or was it just there?

[MsBlack]

If there were no odor and no other reason to suspect infection, then I would guess that at some point earlier--days or weeks earlier--baby had passed mec but it had mainly been cleaned out in the process of amniotic fluid replacement that is perpetually ongoing. Or possibly that only a very small amt of mec had passed, and enough time since then (maybe only a day or 2) for it to have become fairly atomized and distributed (so as to look like a mere stain of the water). In any event, it would not concern me at all, in absence of other concerning signs.

[MsBlack]

But wait, I'm confused about this reason the doc gave for breaking your water....how could he know the water was stained, before breaking it? Did you have sort of minor leak going on that let him see the stain--leading to him breaking sac more fully so he could get a better look at the waters?

[mwherbs]

I probably see about 1/150 mec

one kido with MAS early ultrasound dated pregnancy at 38+week at birth but baby dated out to 36 weeks, baby boy given some replacement surfactant no infection and we didn't resuscitate but did blow by oxygen if we removed the oxygen retractions baby also would not eat.

so 1/20 is 5/100 and 50/1000 that is pretty frequent
do you have much MAS? postdates babies?

[Maggirayne]

No, no leaks. My dr. only saw me for 5 minutes of labour, it was 8 am on Friday. She did ask before doing it, and I think she might have given that as a reason when I hesitated. I remember them looking at the stain in the chux. It was maybe like normal urine.

[MsBlack]

mwherbs--now that I see my number like that '5 in 100', I can see I overstated. Probably 2-3 in 100. Mostly light, flakey, 'old' mec. No MAS. Can't say postdates was an issue--I've seen some 42-43 weekers, no mec. Also no premies (only a few at 36wks, none earlier).

[MsBlack]

Maggirayne--

So the doc wanted to *see* your water to check for staining--that was her reason for breaking your water?

Interesting.