Synthetic oxytocin, which mimics the effects of natural oxytocin on the uterus, was first marketed in the 1950’s, and has largely replaced ergometrine, although a combination drug, called syntometrine, is still used, especially for severe haemorrhage. Syntocinon causes an increase in the strength of contractions, whereas ergometrine causes a large, ‘tonic’ contraction, which also increases the chance of trapping the placenta. Ergometrine also interferes with the process of placental separation, increasing the chance of partial separation. (Sorbe 1978)
Recently active management has been proclaimed “the routine management of choice for women expecting a single baby by vaginal delivery in a maternity hospital" (Prendville 1999), mostly because of the results of the recent Hinchingbrooke trial, comparing active versus “expectant" (physiological) management.
In this trial (Rogers 1998), which involved only women at low risk of bleeding, active management was associated with a post partum hemorrhage (blood loss greater than 500ml) rate of 6.8%, compared with 16.5% for expectant (non-active) management. Rates of severe PPH (loss > 1000ml) were low in both groups- 1.7% active and 2.6% expectant.
The authors note further that, from these figures ten women would need to receive active management to prevent one PPH. They add “Some women … may rate a small personal risk of PPH of little importance compared with intervention in an otherwise straightforward labour, whereas others may wish to take all measures to reduce the risk of PPH."
Reading this paper, one must wonder how it is that almost 1 in 6 women bled after “physiological" management, and whether one or more components of western obstetric practices might not be actually increasing the rate of haemorrhage.
Botha (1968) attended over 26 000 Bantu women over 10 years, and reports that “a retained placenta was seldom seen…blood transfusion for postpartum haemorrhage was never necessary." Bantu women deliver both baby and placenta while squatting, and the cord is not attended to until the placenta delivers itself by gravity.
There is some evidence that the practice of clamping the cord, which is not practiced by indigenous cultures, contributes to both PPH and retained placenta by trapping extra blood (around 100ml, as described above) within the placenta. This increases placental bulk, which the uterus cannot contract efficiently against, and which is more difficult to expel. (Walsh 1968)
Other western practices that may contribute to PPH include the use of oxytocin for induction and augmentation (speeding up labour) (Brinsden 1978, McKenzie 1979), episiotomy or perineal trauma, forceps delivery, caesarean and previous caesarean (because of placental problems- see Hemminki 1996).
Gilbert (1987) notes that PPH rates in her UK hospital more than doubled from 5% in 1969-70 to 11% in 1983-5, and concludes “The changes in labour ward practice over the last 20 years have resulted in the re-emergence of PPH as a significant problem." In particular, she links an increased risk of bleeding with induction using oxytocin, forceps delivery, long first and second stages (but not prolonged pushing) and the use of epidurals, which increase the chance of forceps and of a long second stage.
As noted, western practices do not facilitate the production of a mother’s own oxytocin, neither is attention paid to reducing adrenaline levels in the minutes after birth, both of which are physiologically likely to improve uterine contractions and therefore reduce haemorrhage.
Clamping the cord, especially at an early stage, may also cause the extra blood trapped within the placenta to be forced back through the placenta into the mothers blood supply with the third stage contractions. (Doolittle 1966, Lapido 1971) This “feto-maternal transfusion" increases the chance of future blood group incompatibility problems, which occur when the current baby’s blood enters the mother’s blood stream, causing an immune reaction which can be reactivated and destroy the baby’s blood cells in a subsequent pregnancy, causing anaemia or even death.
The use of oxytocin, which strengthens contractions, either during labour, or in third stage, has also been linked to an increased risk of feto-maternal hemorrhage and blood group incompatibility problems. (Beer 1969, Weinstein 1971)
The World Health Organisation, in its 1996 publication Care in Normal Birth: a practical guide, argue that “In a healthy population (as is the case in most developed countries), postpartum blood loss up to 1000 ml may be considered as physiological and does not necessitate treatment other than oxytocics" In relation to routine oxytocics and controlled cord traction, WHO cautions that “Recommendation of such a policy would imply that the benefits of such management would offset and even exceed the risks, including potentially rare but serious risks that might become manifest in the future"
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