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# WWYD? Elective repeat caesarean or vaginal? - Page 3

Quote:
 Originally Posted by Charles Baudelaire Given the small discrepancy of .02% between maternal mortality rates (.02 to .04%) for VBAC to c-section versus the much larger difference to the baby of .25% (from a .38% chance of death to the .13% chance) for the c-section
That's not quite the way percentages work. Although you can add and subtract them in certain situations, when you want to compare them to each other you have to multiply and divide, because it is about proportion...like percentages of percentages. What I think you really want to say is:

The discrepancy between maternal morality rates for VBAC vs. ERCS is (out of 10,000) 2 vs. 4. 4 is 2 times 2; that is, 200%, or twice the risk.

The discrepancy between child's mortality rates for ERCS vs. VBAC is (out of 10,000) 38 vs. 13. 38 is 2.92 times 13; that is, 292%, or almost three times the risk.

The difference between 2.92 and 2 is a lot less than the difference between 25 and 2. The figure of 25 that you arrived at has some limited validity inasmuch as that many more children die per 10,000, but it's not that much more of a percentage of 13 than 4 is of 2. The relative proportions are not that different.

(I hope I am explaining this OK. This is all just arithmetic I remember from high school; I don't know anything about the actual science of statistics. I hope someone who does know will come along. I find the apparent absence of such a person from these 'cesarean risk' threads very frustrating. 'Cause the one thing I do know about statistics is it's more complicated than it looks, and I suspect these back of the envelope type calculations aren't really getting us too far.)

But anyway, as far as I can tell, it comes down to whether you prefer to tolerate (almost) three times the risk to the child, or two times the risk to the mother.

Assuming this is hypothetical, I am curious why you are mixing up the separate ethical problem of surrogacy/autonomy/"who decides" with the question of maternal vs. fetal risks. Are you just trying to highlight the conflict of interest between child and maternal outcomes, or....? ISTM like we need to figure out what's really going on with the stats before it would be useful to get into any specific ethical scenarios.
Quote:
 Originally Posted by wifeandmom From these numbers, it appears that c-sections are safer for mom when compared to TOL moms attempting VBAC.
Oh. Hmm. When I saw that, I assumed "trial of labor" meant they attempted VBAC and had an emergency cesarean, because it uses different language - TOL vs. elective c/s - from the language for baby's statistics, which compares -"VBAC" to elective c/s. Confusing. And now I'm starting to wonder where the attempted VBACs that end in emergency c/s are showing up in the statistics.
Quote:
 I hope someone who does know will come along. I find the apparent absence of such a person from these 'cesarean risk' threads very frustrating.
LOL! I actually am a statistican, but I have to admit that the way people are adding and trying to compare things is confusing to me. I'm not sure I understand what people are trying to get at. I think some people are confusing mortality (death) rates with morbidity (adverse outcomes, including death) rates.

Quote:
 When I saw that, I assumed "trial of labor" meant they attempted VBAC and had an emergency cesarean, because it uses different language
In the NEJM study, any VBAC attempt is called a TOL. They broke out the maternal and neonatal death and morbidity rates for ERCS, successful TOL (VBAC), and unsuccessful TOL (VBAC).

If you look at the study in a gross way, the best outcomes for mom are in successful VBACs. The next best outcomes are from ERCS. The worst outcomes for mom are in unsuccessful VBACs.

The best outcomes for baby are in ERCS. The next best outcomes are in successful VBAC. The worst outcomes are in unsuccessful VBACs.

If you compare successful VBAC to ERCS, the rates are very, very similar (in a gross way) for mom and babies. The biggest risk with VBAC is if it fails, especially if it fails for a catastrophic reason. Thats when risks for mom and baby go way up.
Thank you so much for clarifying this stuff, Galatea -- I'm normally a reasonably intelligent person, I swear, but when it comes to dealing with numbers, honestly, it's like I lose I.Q. points -- they float out of my ears or something.

Quote:
 . I hope someone who does know will come along. I find the apparent absence of such a person from these 'cesarean risk' threads very frustrating. 'Cause the one thing I do know about statistics is it's more complicated than it looks, and I suspect these back of the envelope type calculations aren't really getting us too far.)
Far enough, anyway, to be able to tell that for the baby, C-section is safer. For the mother, VBAC is safer, but C-section doesn't represent, in terms of a percentage, a huge increase in danger. At least, not if I understood the calculations and your analysis.

Quote:
 But anyway, as far as I can tell, it comes down to whether you prefer to tolerate (almost) three times the risk to the child, or two times the risk to the mother. Assuming this is hypothetical, I am curious why you are mixing up the separate ethical problem of surrogacy/autonomy/"who decides" with the question of maternal vs. fetal risks. Are you just trying to highlight the conflict of interest between child and maternal outcomes, or....? ISTM like we need to figure out what's really going on with the stats before it would be useful to get into any specific ethical scenarios.
I'm trying to understand the conflict between maternal and fetal risks in order to come to a more clear understanding of what the most ethical choice would be.

If it were her own baby, Jane would do a VBAC -- but Jane has a child already and could have more if she chose. Jim and Janet have this one child. That's it. Forever. They care very much for Jane's welfare, so they don't want to make a choice that puts her health at risk (well, more than it's at risk already in general for birth, but they all know birth has risks). They are also understandably scared that their one-and-only child will die -- something I know every mother on here can sympathize with from the bottom of her heart...we've all been there. That's why they lean more toward c-section. Jane would prefer a VBAC, but she will do a c-section if that, overall, is the safest choice for both Jane and the baby. Determining what is "safest" though -- that is the question.

Thank you so much for taking the time to explain more about percentages...I really thank you.
Quote:
 Originally Posted by GalateaDunkel That's not quite the way percentages work. Although you can add and subtract them in certain situations, when you want to compare them to each other you have to multiply and divide, because it is about proportion...like percentages of percentages. What I think you really want to say is: The discrepancy between maternal morality rates for VBAC vs. ERCS is (out of 10,000) 2 vs. 4. 4 is 2 times 2; that is, 200%, or twice the risk. The discrepancy between child's mortality rates for ERCS vs. VBAC is (out of 10,000) 38 vs. 13. 38 is 2.92 times 13; that is, 292%, or almost three times the risk. The difference between 2.92 and 2 is a lot less than the difference between 25 and 2. The figure of 25 that you arrived at has some limited validity inasmuch as that many more children die per 10,000, but it's not that much more of a percentage of 13 than 4 is of 2. The relative proportions are not that different. (I hope I am explaining this OK. This is all just arithmetic I remember from high school; I don't know anything about the actual science of statistics. I hope someone who does know will come along. I find the apparent absence of such a person from these 'cesarean risk' threads very frustrating. 'Cause the one thing I do know about statistics is it's more complicated than it looks, and I suspect these back of the envelope type calculations aren't really getting us too far.) But anyway, as far as I can tell, it comes down to whether you prefer to tolerate (almost) three times the risk to the child, or two times the risk to the mother.
In another lifetime, I taught high school math, so I understand how percentages work.

What you are saying is true, the risk to mom is 2x greater for c-section vs. VBAC and the risk to baby is ~3x greater for VBAC vs. c-section.

However, it's perfectly valid to look at the raw data as well, which is what most people have been doing. The reason you 'see' more of a difference in the raw data in this case is because for the c-section risk, you start out with 2 moms dead from VBAC and 4 from c-section. With c-section risk to baby, you have 13 dead babies vs. 38 dead babies from VBAC.

So, while you are absolutely correct that the numbers are 2x the risk for section (to mom) and ~3x the risk for VBAC (for baby), you are starting with a much larger number of dead babies (13 dead with c-section), so roughly 3x that risk is what gives you 38 dead babies with VBAC.

Indeed you WILL have 25 ADDITIONAL dead babies in VBAC attempts vs. ERCS. We ARE talking about 25 out of 10,000, still a very small number, but valid nonetheless.

I think the problem comes in when people use varying ways to look at percentages to 'prove' their point. Obviously in this case, it looks 'worse' for VBACs to use raw numbers (the fact that 25 additional babies will die instead of just giving the .13 and .38 which most people don't really understand in the first place, they just both look really, really small).

How many times have I seen something like 'Elective section moms are TWICE as likely to die as vaginal delivery moms' or some such statement. Yet you rarely see those same people point out that we're talking 1 in 5000 vs. 1 in 10,000. Or even better are those who don't acknowledge the difference in stats between unplanned c-sections (1 in 2500 deaths for mom) vs. elective c-sections ( 1 in 5000 deaths for mom).

Another example that comes to mind is something I read recently that said very boldly 'C-section babies are FIVE TIMES more likely to have PPH.' There was ZERO mention of how likely PPH is in a newborn to begin with, and for me, that's a critical piece of information if the whole FIVE TIMES AS LIKELY business is going to be a major concern or something still so very rare that it's worth noting but not stressing over. (Off to look up actual stats after I post this as I am curious....)
Ok, here's the first easy to read explanation I found:

Quote:
 Who is affected by persistent pulmonary hypertension? About one in every 500 to 700 babies develops PPHN. It occurs most often in full-term or post-term babies after a difficult birth, or birth asphyxia (a condition that results from too little oxygen).

From this, it sounds more like an issue of difficult birth, which obviously ends up in c-section much more often if baby isn't getting enough oxygen. So while it may very well be true that 5x more c-section babies have PPH in comparison to vaginal birth babies, it sounds to me like the CAUSE has zilch to do with the c-section and more to do with the fact that the baby was in trouble to begin with.

I wonder what the stats are for ERCS babies under NO distress in comparison to vaginally birthed babies. If THOSE babies also see a five fold increased risk in PPH, then there might be something noteworthy to consider, as I don't consider 1 in 500 to 700 (thus increasing the risk to close to 1 in 100 for c-section babies) a tiny number. It's not HUGE, mind you, but it is concerning IF the ERCS babies are seeing the same risk increase.
Quote:
 Originally Posted by wifeandmom How many times have I seen something like 'Elective section moms are TWICE as likely to die as vaginal delivery moms' or some such statement. Yet you rarely see those same people point out that we're talking 1 in 5000 vs. 1 in 10,000. Or even better are those who don't acknowledge the difference in stats between unplanned c-sections (1 in 2500 deaths for mom) vs. elective c-sections ( 1 in 5000 deaths for mom). Another example that comes to mind is something I read recently that said very boldly 'C-section babies are FIVE TIMES more likely to have PPH.' There was ZERO mention of how likely PPH is in a newborn to begin with, and for me, that's a critical piece of information if the whole FIVE TIMES AS LIKELY business is going to be a major concern or something still so very rare that it's worth noting but not stressing over. (Off to look up actual stats after I post this as I am curious....)
That's precisely the kind of thing I'm talking about. Jane's concern with a C-section is that she'd die -- not a surprise, given that ERCS stats vs. VBAC stats are usually put in terms of "X times more/less likely than Y," and it's why I wanted BOTH figures in terms of a percentage..sort of to level the playing field.
Quote:
 Originally Posted by wifeandmom Ok, here's the first easy to read explanation I found: From this, it sounds more like an issue of difficult birth, which obviously ends up in c-section much more often if baby isn't getting enough oxygen. So while it may very well be true that 5x more c-section babies have PPH in comparison to vaginal birth babies, it sounds to me like the CAUSE has zilch to do with the c-section and more to do with the fact that the baby was in trouble to begin with. I wonder what the stats are for ERCS babies under NO distress in comparison to vaginally birthed babies. If THOSE babies also see a five fold increased risk in PPH, then there might be something noteworthy to consider, as I don't consider 1 in 500 to 700 (thus increasing the risk to close to 1 in 100 for c-section babies) a tiny number. It's not HUGE, mind you, but it is concerning IF the ERCS babies are seeing the same risk increase.
From what I can see, to say that c-section babies have PPH five times more often than vag birth babies is genuinely putting the cart before the horse: it sounds like the CS may have been a response to fetal hypoxia, not the cause of it.
Quote:
 Originally Posted by Charles Baudelaire From what I can see, to say that c-section babies have PPH five times more often than vag birth babies is genuinely putting the cart before the horse: it sounds like the CS may have been a response to fetal hypoxia, not the cause of it.
That's what I'm thinking, but have been unable to find a whole bunch of actual statistical evidence on elective c-section with NO fetal distress present at delivery and subsequent PPH risks.

Stats are played both ways, and it's very frustrating, esp considering the average American hasn't a clue how to interpret stats. My high schoolers in the classroom literally shut down when they saw a fraction or decimal. Word problems? Ha! It makes it hard for anyone to actually read and UNDERSTAND the risks they are taking when you have to consider the source of information so carefully.

Obviously a site supporting VBAC is going to word risks of ERCS in the worst sounding way possible, which is really a shame cause it seems to work on the assumption that a woman can't possibly make an informed choice if given the WHOLE picture.
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