We need a better way of defining postpartum haemorrhage...

It was good to see a paper in the American Journal of Obstetrics and Gynecology this month calling for a better way of defining postpartum haemorrhage (PPH).

Borovac-Pinheiro et al (2018) write that, “The current definition of [postpartum haemorrhage] is inadequate for early recognition of this important cause of maternal death that is responsible for >80,000 deaths worldwide in 2015. A stronger definition of postpartum hemorrhage should include both blood loss and clinical signs of cardiovascular changes after delivery, which would help providers to identify postpartum hemorrhage more promptly and accurately. Along with the amount of blood loss, clinical signs, and specifically the shock index (heart rate divided by systolic blood pressure) appear to aid in more accurate diagnosis of postpartum hemorrhage.”

One reason that I find this so interesting is that Nadine Edwards and I have recently updated Birthing Your Placenta; a popular book written to help women make decisions about the birth of their placenta, which is also very popular among midwives, doulas, childbirth educators and other birth workers!

In Birthing Your Placenta, we examine the different options, detail the evidence relating to each and discuss the wider context in which these decisions are made, and the definition of PPH is an important thing to consider among all of this. As I have been saying and writing for years, it is no good solely relying on a numerical estimation of blood loss. That’s partly because humans are notoriously poor at estimating blood loss but, even where more accurate methods of estimation are in use, women differ in the way in which their bodies can cope with losing different amounts of blood. A tiny, poorly nourished woman might not be very well after losing 500mls of blood, while a large, healthy, robust and well-nourished woman might not be compromised even if her blood loss is double that. Though I don’t want to make it sound that it’s all about size or nutritional status either; there’s so much more at play here!

Borovac-Pinheiro et al (2018) also note the illogical way in which, because we know that caesarean section leads to a greater average blood loss than straightforward vaginal birth, women who have a caesarean section in many areas of the world are not deemed to have had a PPH if they lose 500mls of blood, while women who have given birth vaginally are. “The different PPH definitions by delivery method are even more confusing: why would a blood loss of 500 mL represent a risk for women after vaginal delivery but not for a cesarean delivery? In addition to the wide range of normal postpartum blood loss values, the arbitrary cutoff lacks clinical accuracy.” Borovac-Pinheiro et al (2018).

These authors go on to propose the use of the Shock Index (SI) and anyone interested in looking more deeply at this can find their article here. But whichever measure we use, as with so many things, it’s all about looking at the individual, not just the population measure or average. So it’s great to see these debates occurring in different journals and from different perspectives.