Obstetric Blinders: Cord Clamping

In my last post on obstetric blinders, I quoted a 1970 article that discussed upright birth among the Bantu and Polynesian people. That article quoted M.C Botha's 1968 article on the management of the umbilical cord in labor from the South African Medical Journal. (Full text here.)

I managed to track it down and was blown away by what I found--both by the evidence against cord clamping and by the obstetric blinders that Botha wore.

Botha's article begins with some quaint observations about childbirth in the Bible and other ancient literature. Botha then examines "primitive" birthing practices:

The most primitive of the Bantu people believe that it is completely wrong to touch the cord until the whole placenta is expelled. Once bearing-down pains commence, the parturient woman sits on her haunches, as if in defaecation. The trunk is bent forward, thus increasing the intra-abdominal pressure. Her bearing-down efforts are not new to her, since she has repeated the same act in defaecation daily since she was born.

Once the baby is born, the woman (Fig. 1) will remain in a squatting position watching her new baby. The placenta delivers itself from the vagina without any maternal effort (Figs. 2 and 3). Once the placenta is delivered, by gravity, the membranes usually remain in the vagina. The patient then lifts herself on her haunches and the membranes fall out. Only now does she pay attention to the cord (Fig. 4).

Hooten [1 sic] reported the same observations. Vardi [2], on account of this observation by Hooten, investigated the extra amount of blood that can be transfused into the baby by gravity; the residual blood in the placenta was approximately 11.2 ml. By bleeding the cord the total average blood volume was 100 ml. They thus concluded that by gravity, and not clamping the cord, the baby gets an extra 89 ml. of blood. This is exactly what happens in the Bantu baby.

Working among the Bantu for 10 years, attending 26,000 Bantu and seeing only abnormal cases, I found many other complications, but a retained placenta was seldom seen. If called to a case, I usually found that the terminal part only of the membranes was still in the vagina, and had merely to be lifted out. Blood transfusion for a postpartum haemorrhage was never necessary.

It gets more interesting. In the next paragraph, Bantu writes:

In accordance with this observation, the third stage of labour in White patients was managed with the use of Syntometrine [Pitocin], letting the cord bleed, and the Brandt-Andrews manoeuvre, and in 800 cases over the past 10 years no retained placenta or postpartum haemorrhage needing blood transfusion has been found. 

Note the difference in care between Bantu women (cord left intact) and White women (oxytocics, managed 3rd stage, cord clamped on the baby's side and left to bleed on the maternal side). Bantu babies also received an "extra" 90 ml of blood compared to White babies.

Let's see what else this article has to offer. I'm going to skip the next section on the history of cord clamping from the 16th century to the present. It's worth reading on your own, however.

Next, Botha discusses a study he conducted on a consecutive series of 60 unselected women, 30 with clamped cords and 30 intact cords. In both groups, "the uterus was not handled after the birth of the baby. The placenta was not handled until the mother felt the urge to bear down herself and was only received when it appeared outside the vagina. No oxytocic drugs were used." Women with intact cords birthed their placentas much more quickly and with much lower blood loss, compared to women whose cords were clamped.

Botha did another study in which he injected dye into the placenta immediately postpartum via the umbilical vein and took a series of X-rays to visualize the descent and birth of the placenta. He found that placentas with unclamped cords delivered more quickly than placentas with clamped cords.

Let's go to the end of the article, now, in which Botha discusses his findings. He begins with an unsurprising observation: "In the cases where the cord was not clamped in the third stage there was a statistically significant difference in duration and blood loss compared with those where the cord remained clamped."

Further down, he notes that an upright maternal position helps the placenta birth rapidly and with little resistance:

As there is fundal dominance in uterine activity, the placenta is forced in the direction of least resistance towards the lower segment and vagina. If the cord is bled, this process is so rapid that retraction has not yet taken place in the cervix, and the placenta, reduced in size, is expelled without resistance into the vagina. If the patient is sitting on her haunches, it will fall out by gravity.

Skipping ahead a bit more:

If the cord is clamped, counter-resistance from the placenta may be so great that retraction may come to an end. The placenta will then be separated by retroplacental blood, which, in my opinion, is not normal but abnormal. this takes place slowly and by the time the placenta is separated the cervical muscle has also retracted. The placenta is bulky, due to the blood it contains, and expulsion is difficult. If expulsion is not possible, the inevitable result is that in a certain percentage of cases the placenta will be retained, with associated postpartum hemorrhage.

Botha notes several times that the baby receives an "extra" 90 ml of blood if the cord is left intact. (I suggest phrasing it in the inverse: when the cord is clamped, the baby loses 90 ml of blood.) His next paragraph again mentions the difference in blood received by the baby:

If the cord is not clamped until the placenta is expelled, the baby will receive an extra amount of blood, which is approximately 90 ml., as reported by Vardi. 

He also notes that Rh- sensitization is rare when the cord is left intact and the placenta is birthed spontaneously.

The conclusion is fascinating--and disturbing--in how firmly Botha's obstetric blinders were in place. I had expected his conclusion would recommend leaving the umbilical cord intact until the placenta is birthed. This would both reduce both retained placenta and postpartum hemorrhage and give the baby its full blood volume. But instead, Botha recommends a surprisingly complicated method of third stage management:

Ironically, midwives would be giving superior care by simply leaving the cord intact and waiting for the birth of the placenta, because the baby would also retain 90 ml of blood in the process.

This is a classic example of how "modern" obstetrics pursues an invasive and complex solution (oxytocic drugs, bleeding the placenta, removing the placenta with controlled traction and pressure on the uterus) while discarding the simpler, better solution (leaving the cord intact and waiting for the placenta to birth on it own)--even though the "primitive" solution is easier for the attendant and better for the baby. 

References

1. Hooton, Earnest A. Man's Poor Relations. 1st ed. New York: Doubleday, 1942. p. 412. (Corrected from the original)
2. Várdi, P.: Placental transfusion: an attempt at physiological delivery. Lancet 2:12–13, 1965.