Post-partum Haemorrhage
In the previous edition of Pregnant, Dr. David Kiragu explained what Postpartum Haemorrhage (PPH) means, the two categories – Primary and Secondary – and the fact that PPH can lead to maternal death.
PPH is largely unpreventable. The majority of patients who get PPH have no history or clinical features that would be predictors of that eventuality. So in as much as we have alluded to women who are grande multipara and women who have had Caesarean sections as being particularly at risk of having PPH, the reality is that majority of women who have PPH do not fall in groups that will be described as high risk. Therefore every pregnant woman is potentially at risk of getting PPH and every pregnant woman ought to be managed in an environment that can manage PPH or can be easily referred to a facility that is competent to manage PPH.
What causes postpartum haemorrhage?
o Hypotonic uterus – This is a uterus that fails to contract after delivery. After delivery has been concluded the uterus is expected to contract. Those contractions constrict the blood vessels within the region where the placenta was attached.
Once the placenta is pulled out (expelled) during the third stage of labour it literally leaves a wound. Therefore the contractions serve to constrict the blood vessels within the bed where the placenta was before. If the uterus does not contract then the vessels will continue to bleed.
A hypotonic uterus is particularly common in women who have had relatively many deliveries, particularly more than 5 children. Such women are referred to as grand multipara. They are more vulnerable to a hypotonic uterus.
Another cause for a hypotonic uterus is when the delivery accurs very quickly, if a woman delivers very suddenly, may be an hour from start to finish of labour,referred to as precipitate labour, that can lead to hypotonic uterus.
o Genital tears – During delivery one might get tears of the cervix or major lacerations on the vagina. If not repaired in time they can lead to massive loss of blood.
o Ruptured uterus – This is a situation where the uterus sustains a tear due to excessive pressure. Uterine rupture may occur in various instances, for example where a woman had a previous Caesarean delivery and then tries to have a normal delivery, it is also more likely to occur in women who have had many children and is likely to occur in women who have been administered drugs (induced or augmented labour) to strengthen the contractions, if not closely monitored and regulated.
o Retained placenta – This is a placenta that has failed to come out. it can occur after a successful delivery if a fragment of the placenta or membranes are retained within the uterus. This bleeding normally occurs later than 24 hours after delivery, and is referred to as secondary PPH.
Other rare causes of PPH include:
o Intrauterine foetal death. If the foetus has been dead for more than three weeks, blood loses its capability to clot and the bleeding is continuous. Blood needs to clot within the blood vessels in the uterus for bleeding to stop so in situations where the clotting is compromised one gets PPH.
o Amniotic fluid embolism. In this case, the amniotic fluid enters into maternal blood vessels during labour, initiating chemical changes within the blood, which prevents clotting of blood and leads to PPH.
o Placenta abruption. This is where the placenta is partially or completely detached from the wall of the uterus after the 24th week of pregnancy. When that happens a mother loses the ability of blood to clot, leading to PPH.
Every pregnant woman is potentially at risk of getting PPH and every pregnant woman ought to be managed in an environment that can manage PPH.
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