Conflicting studies

Ok, so long story short, I happened across these two articles from the UK, both from the same woman, Medical Editor Rebecca Smith, which had conflicting results. The first report, written almost exactly a year ago, was titled, “Death Risk Higher for Women ‘Too Posh to Push’“; and the second report, written this past April, was titled, “Women Choosing Cesarean Have Low Death Rate.” I’ll see if I can find something like the actual study, and not just go by what the author said about the study, but just had to say this while it was fresh on my mind.

The first report was published in the BMJ (which if I remember correctly has all of its articles available free online, so it should be easy to find), and Ms. Smith reported that the study found that

the risk of maternal death was three to five times higher compared with natural deliveries. The risk of requiring a hysterectomy after a caesarean section was four times higher than for a natural birth and twice as high for being admitted to intensive care and needing a hospital stay of more than seven days.

For babies in a breech position, a caesarean section was safer but for those in a normal head-first position the risk of the baby dying or suffering serious problems was raised by one and a half times. Experts said the study was a “reality check” that caesarean sections carry risks and are not ‘just another delivery option’.

The second report was attributed to “The Birth Trauma Association”, an organization in the UK, and I’m not sure if the report was actually published anywhere, but I’ll try to find it.

The Birth Trauma Association found that of the 2,113,831 women who delivered a baby after 24 weeks gestation between 2003 and 2005, one in 10 had a caesarean before labour had begun.

Seven women died, giving a mortality rate of 0.31 per 10,000.

This compared to 74 deaths amongst the remaining women who had a natural birth or an emergency caesarean section, giving a mortality rate of 0.39 per 10,000.

Since reports published in well-respected peer-reviewed medical journals such as the BMJ typically analyze the results to see if they are statistically valid, I will assume that the data reported in the BMJ article is statistically significant; I’m not sure about the other — we’ll have to see.

The question that weighs most heavily on my mind is, what is the maternal mortality rate among women who had a vaginal birth? And the morbidity rate of the infants?

Most studies that are undertaken to look at mortality and morbidity in birth will typically restrict participants to be only those in the term period (unless they are looking specifically at pre-term births). There is no definition of “emergency” C-section given, so I am going to assume that it just means any unplanned C-section. I will accept that surgeries performed under stressful situations (such as an absent fetal heart-rate, in which the baby will need to be cut out immediately) may predispose the mother to extra risks due to the probability that the doctor is cutting faster and not taking as much time as in a scheduled C-section. So, what things can be done to reduce the rate of fetal distress? I’m unsure if other factors play into this — such as if having a pre-term C-section may cause more problems than having a term C-section; or a failed induction for non-medical reason ending in an “emergency” C-section. Also, I’m curious if only 10% of women had planned C-sections. It seems probable to me that there would be many women who planned a C-section but actually went into labor before the date of the scheduled surgery, so were automatically included in the 2nd group, which combined women who gave birth vaginally with those who had a C-section after labor began.

There may have been many women who had pre-term labor and had their babies by C-section because their babies were so small that they may have been traumatized by such an early vaginal birth. I seem to remember reading somewhere that in very early pre-term births, C-section is the preferred birth mode because of the delicate condition of the baby, specifically the head trauma he may endure being so fragile, going through the birth canal; plus the fact that many babies are still in the breech position in early pregnancy, and would be put at severe risk if allowed to be born vaginally — their heads are much more out of proportion to their bodies that term babies (this means that there may be more complications like head entrapment in a partially dilated cervix). If women at 24-30 weeks present to the hospital in pre-term labor that the hospital can’t stop, it is likely in their babies’ best interests to be born by C-section. Since the women were in labor before the C-section began, they would not be included in the first group, yet it isn’t exactly fair to include them in the planned vaginal birth group since they didn’t even make it to term, and most C-sections done prior to the beginning of labor would take place during the term period. It makes a difference for the babies; it might make a difference in the mothers. There are some preterm C-sections that do take place prior to labor beginning, such as some for twins or other multiples, or those in which the baby seems to be not developing well in utero, or he stops moving or something.

Anyway, I’m looking forward to trying to find this report, and seeing if it answers some of the questions, or if they give a statistical analysis to back up their claim of a lower maternal mortality for planned C-sections. Comparing it to the BMJ (which is almost certainly statistically significant), it surprises me that such a large difference noted by the BMJ article is contradicted but with only a slight difference by this other report. It may mean nothing more than that C-section after failed induction is a hidden risk factor for higher maternal mortality; or that an emergency C-section done because the baby’s heartrate plummeted after the mother’s blood pressure took a nose-dive after she got an epidural helped to increase the MMR. The BMJ reported that maternal death was 3-5x higher for C-sections (but the article I read did not say whether that looked at planned vs. unplanned C-sections), whereas the higher rate of maternal death for vaginal births and C-sections which took place after labor began was only 8 per million higher (3.1/100,000 vs. 3.9/100,000) — very slight. Considering all of the other risks of C-section (especially repeat C-section, with the higher rate of complications including placental problems with future pregnancies and hysterectomies, not to mention things like maternal hemorrhage and blood transfusions and risk of infection and pain), I think that women need to look at the full picture of both what vaginal and surgical birth have to offer and what the risks and benefits of each are.


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