Recently, I wrote about the increased risk of placenta accreta or percreta due to a previous C-section. While the risk of placenta problems definitely increases exponentially for every previous Cesarean, there was something in the article that bugged me:

Studies and textbooks suggest that the risk of developing an accreta is as high as 40 percent in women who have had two previous Caesareans; that jumps to 60 percent with three C-sections, their physicians said.

Although I’m a strong proponent of vaginal birth, I do want to be truthful about C-sections, and I don’t think the above sentence is accurate. It just seems too high. Running some numbers — there are about 4 million births per year, and about 30% of them are C-section. I think that approximately 40% of annual C-sections are first-time sections, while the remaining 60% are repeat sections, or about 720,000. I haven’t looked it up, but I would hazard a guess that of the repeat surgical births, half of them are a second C-section, while the remainder would be a third or higher C-section. If the risk of accreta really were 40% after a second C-section, that would mean that 144,000 women would be at risk every year of developing placenta accreta. I just don’t think it’s that high. That would be 3.6% of all pregnant women developing accreta, or 36/1000. The article quotes current rates of accreta as ranging from 1/500-1/2,500 births, or 0.002-0.0004 — 18-90 times less than .036. So, even if some of my hypothetical numbers are wrong, there’s still plenty of wiggle room between “40-60% risk of developing placenta accreta” and 1/500-1/2,500.

Probably what happened is the reporter got confused, and misunderstood some of the literature. In trying to get to the bottom of this — to see if the risk of developing placenta accreta or percreta was really as high as the article quoted — I saw that there were numerous times when the phrase “placenta accreta/previa” was used. The gist of the articles and studies I read, was that when a woman has placenta previa (the placenta grows over the opening of the uterus — which is also more likely to happen after a prior Cesarean), then her risk of also developing placenta accreta is very high — along the lines of the percentages given in the quote. But if a woman does not have placenta previa, then her risk for placenta accreta — while it does increase exponentially with every C-section — does remain fairly low, and nowhere near the 40-60% risk solely due to past C-sections.

Another possible misunderstanding the author may have had was along these lines — finding that women who had accreta or percreta were much more likely to have had C-sections (which is very true), and getting the percentages or risks for that confused with the risks for developing accreta or percreta to start with. While I don’t know if this was the case, I have read many things (not just birth-related) in which journalists screwed up in a similar fashion. I’ll give you an exaggerated example of how easy it is to confuse matters, if you didn’t know any better:

Let’s say that about 86% of all women who choose home birth in the United States are both white and married. A journalist could easily get a bit muddled and report that in the United States, 86% of white, married women give birth at home. Since you and I are knowledgeable and educated birth junkies, we know that only about 1% of all births in America take place out of the hospital, so we would never be taken in by this misstatement. But others might. The two statements are very similar — an accurate percentage is given, and the details (home birth, white, married, United States, women) are all the same. But you can see the obvious difference between the two statements.

I should have caught the problem before I wrote my previous post; but since I didn’t, I wanted to clarify.


Well It’s About Time!

If you’re a faithful reader of this blog and/or a fellow birth junkie, the following article will not come as a big surprise — Cesarean Sections Linked to Future Birth Risks. It warns of the dangers of placenta accreta or percreta in future pregnancies (accreta is when the placenta implants too deeply into the uterine wall; percreta is when the placenta actually grows through the uterine wall and attaches to other organs). The only surprising factor to me was that it was an article in a non-birth publication which strongly warned of the danger of C-sections. All too often, the standard argument in most mainstream articles (and by that, I mean non-birth-oriented publications) is a “balanced” picture of C-sections versus vaginal birth, with the pros and cons of both sides being presented as basically equal. There are pros and cons to both sides, but that doesn’t mean that they are balanced or roughly equal. If a mom or baby truly needs a C-section, then obviously, the balance tips dramatically in the favor of a C-section; but if the surgery is not medically necessary, then vaginal birth obviously is favored for both mom and baby.

The first mom mentioned had placenta percreta (in which the placenta grows through the uterine wall, and in her case invaded her bladder), forcing the doctors to end her pregnancy 4 months early. Her baby is still struggling to survive, and she lost her uterus. She wanted four children. She says after her first baby was born by C-section, she expected “lots of C-sections” in order to have the size of family she wanted — I guess she was told “once a C-section, always a C-section,” because it doesn’t sound like she even thought of attempted VBAC. Not that it ultimately mattered in her case, since her first post-op pregnancy cost her her uterus, but placenta accreta and percreta increase exponentially with every additional surgery, so for many women, it may be their 2nd, 3rd, or 4th unnecessary C-section which costs them their ability to bear children, and possibly the life of their baby, and even potentially threatens their own life.

The article also quotes the rate of placenta accreta as being 1/30,000 in the 1950s, but current studies show a rate of 1/2500-500! Yikes!

I’ve seen some “VBAC Consent Forms” which pretty much magnify the risks of VBAC, particularly uterine rupture, which can be devastating or even deadly for the baby. But the risk is small, especially in labors that are allowed to begin or continue naturally; and if the care providers are monitoring the mother and baby, they can usually get early warning that something is wrong (like the mother feeling the pain of her uterus splitting, or the baby’s heartbeat showing signs of distress), so the absolute risk of death or severe morbidity to the baby is low. Often the consent forms tell the mother that if she has a VBAC, her baby is the one that will be put at risk, whereas if she chooses a C-section, then she’ll be the one that has more risks (from the actual surgery, which has a higher rate of blood loss necessitating transfusion, risk of hysterectomy, infection, etc.). Put that way, most women will feel selfish for wanting a vaginal birth, so sign up for a repeat C-section. However, this article points out that even one C-section increases the risk of future placenta accreta/percreta, and each repeat C-section increases the risk exponentially, so mothers may be choosing a repeat C-section to keep their current baby from the 1/200 risk of uterine rupture (with an even less risk of death or severe morbidity), while setting up a future baby to be in the position of the first baby mentioned in the article — being born much too early, and possibly dying or having severe long-term difficulties. Plus the mother may hemorrhage and necessitate a blood transfusion (perhaps even massive), and/or lose her uterus.

Read the entire article, because it is very informative. I wonder how many women are truly given informed consent before their first C-section, or any subsequent ones. Time for a VBAC-lash!

Legal help for VBAC bans

One of the most pernicious problems with a primary (first-time) C-section, is that so many women nowadays are being denied the right to have a subsequent vaginal birth, and are required to have an “elective” repeat C-section. Some doctors refuse to attend them; some hospitals have it as policy that VBACs are not allowed. A large part of this problem is the malpractice insurance provider for either doctor or hospital that has it as part of their policy that they will not cover doctors or hospitals who participate in VBACs. The reason is the possibility of uterine rupture, which though rare is a known risk factor in an attempted VBAC (Overall — 7/1000 in that study — and this probably includes both catastrophic uterine rupture as well as the more benign uterine dehiscence; the breakdown goes as follows: Spontaneous TOL: 7/1544 or 4.5/1000; Prostaglandin E2 gel: 5/172 or 29/1000; Foley catheter: 1/129 or 7.75/1000; induction w/o cerv. ripening: 2/274 or 7.3/1000). The fact that other potential problems that can affect all women and their babies (such as a cord prolapse [2.34/1000, 4/1000, & 1.7/1000 were all figures given in published research; and this study said that obstetrical interventions contribute to 47% of cord prolapses], or placental abruption [9.9/1000, 6.5/1000]) together take place more than the known uterine rupture risk in an attempted VBAC (provided drugs like Pitocin, Cytotec and Cervidil or Prepidil are not used), does not alter the equation at all. It seems to me that the risks to the doctor ought to be the same, but since a previous C-section is a known risk factor for uterine rupture, and because ACOG has made it their guidelines that surgery be “immediately available” to a woman who attempts a VBAC, many hospitals are interpreting this as saying that a full surgical team must be in-hospital the entire time a VBACer is there in labor. Many hospitals, especially small rural ones, do not have this, so many women are being denied their legal rights by having an unwanted surgery forced on them, by an administrative decision made by a body of obstetricians, which is not legally binding. However, if a VBAC goes bad, and the woman decides to sue, you can bet your bottom dollar that the woman’s lawyer will bring up the ACOG guideline as if it were The Eleventh Commandment.

As I wrote in an email to an ICAN group,

So if they don’t induce or augment TOLACs, the rate (which may include dehiscence which is generally not associated with negative perinatal outcomes) is 4.5/1000, which is less than the rate of placental abruption — although women are not required to be at the hospital from 20 weeks onward, just in case their placentas suddenly decide to separate, and PA is definitely associated with higher perinatal morbidity and mortality (partly but not completely due to premature births) than is UR in labor, especially with dehiscence. Obstetric interventions contribute to almost half of all cord prolapses, which may be as high as 4/1000 (almost the rate of UR in TOLACs) but I bet docs aren’t required to be at the hospital before the L&D nurse is allowed to break any woman’s amniotic sac, or otherwise intervene. This study said that these interventions were not associated with higher perinatal morbidity and mortality, presumably because the woman was already at the hospital and quick action was taken. If this can happen for these women, why not VBACers?
This also doesn’t begin to touch the future problems women may encounter during pregnancy and birth should they have multiple C-sections, which they will be required to do, if they can’t have VBACs and want more than 2 kids. I guess I should look up rates of placenta accreta/percreta/previa in uteri that are unscarred vs. 1 C-section, 2 C-sections, etc. These not only pose potential hazards for that baby but for the mom as well — and C-sections are more strongly associated with AFE than with vaginal births, too, which has a high maternal and perinatal mortality and morbidity.
Click here to see what the free legal help offered in overturning VBAC bans is — even if you’re not personally involved — even if you, like me, have never had a C-section so VBAC is not even in your considerations. You should keep this information in mind — bookmark it, even, so you can find it easily in case you in the future are pregnant after having had a C-section, or you have a friend who is. Considering that 1/3 of American women each year have a C-section, the odds that you’ll know somebody who may need this information is pretty high.