Planned C-section vs. planned vaginal birth

Here is an interesting study from Canada, though not without fault. In brief, the authors took a group of (apparently otherwise low-risk) women who were having a planned C-section due to breech presentation, and compared the rates of maternal morbidity and mortality to low-risk women who planned a vaginal birth. Since many women who plan C-sections are at high risk, the authors did not include any other planned C-sections — there were no codes for C-sections performed without indications — that is, truly elective C-sections, so they selected the breech births as a comparable cohort. Many other women were excluded — the usual kinds — preterm birth, multiple gestation, etc. — to try to get two low-risk similar if not matching groups.

Outcomes of interest included maternal mortality (in-hospital deaths only) and severe morbidity (intra-and postpartum). Severe maternal morbidity was defined as the presence of one or more of the following complications: hemorrhage requiring hysterectomy, hemorrhage requiring blood transfusion, any hysterectomy, uterine rupture, anesthetic complications (including those arising from the administration of a general or local anesthetic, analgesic or other sedation during labour and delivery), obstetric shock, cardiac arrest, acute renal failure, assisted ventilation or intubation, puerperal venous thromboembolism, major puerperal infection, in-hospital wound disruption and hematoma. Length of hospital stay for childbirth was calculated by subtracting the hospital admission date from the discharge date.

Here is the table with all of the morbidity rates for the two groups: planned C-section for breech presentation, and planned vaginal births (although some of these ended in C-section).

Obviously, successful vaginal births (whether spontaneous or induced) had a lower rate of these problems than planned C-sections; and most of the problems in the “planned vaginal birth” group were in births that became unplanned C-sections. It wasn’t mentioned whether some of the problems led to an emergency C-section, or if the C-section led to the morbidity. For instance, if a woman has an amniotic fluid embolism, the mortality and morbidity rates for both mother and baby are very high; and about the only thing doctors can do is an emergency C-section and probably a hysterectomy. Also, if there is a placental abruption that manifests in a hemorrhage, the woman would be taken for an emergency C-section, and may need a blood tranfusion because of the initial blood loss, rather than due to the C-section itself.

Although no women died in the breech C-section group and some did in the planned vaginal birth group, the authors concluded that this was not significant. (The rate of maternal mortality in the “planned vaginal birth” group was less than 1/50,000, so even without statistical analysis, it is not difficult to see that 0 deaths out of less than 50,000 births in the C-section group is similar, especially when maternal mortality is relatively rare anyway.) The authors mentioned that the rates of morbidity were similar to other published rates of maternal mortality associated with planned C-section, implying that had the study been larger (although it encompassed over two million women over 14 years), it would have found similar results as other studies.

One medical problem that women in the planned vaginal birth group had at a higher rate than the planned C-section births was in hemorrhage requiring transfusion. This was offset by a reduction in rates of hemorrhage requiring hysterectomy. The authors concluded that what most likely happened is that if a woman who was having a C-section began to hemorrhage, the doctors simply removed her uterus to stop the blood flow. This resulted in less total blood loss and fewer transfusions, but in more women without wombs, when all was said and done. When a woman who was not having a C-section began hemorrhaging, the doctor tried different means of stopping the blood loss other than hysterectomy, using that as a last resort; this resulted in more blood being lost which led to more transfusions, but also in more women keeping their ability to have children.

As a footnote, I will point out that in this study, as in many others, the authors define any unplanned C-section as an “emergency”. I don’t like that division, since most of the C-sections I’m aware of personally have been unplanned as well as non-emergent surgeries. It’s not like the babies’ heartrates were crashing or anything; many C-sections are due to passing somewhat arbitrary timelines (FTP — “failure to be patient” or “failure to progress”) although both mother and baby are doing well. I just recently read a story of a woman whose obstetrician willingly let her push for something like 11 hours — yes, you read that right — she PUSHED for eleven hours, not just labored that long! — because the baby’s heartbeat was fine throughout. (The mother was also tolerating labor well — the doctor would have done a C-section had the mother wanted it — he wasn’t forcing the woman to labor. But as long as the baby was fine and the mother was fine, he wasn’t going to force or push a C-section.)


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