Postpartum hemorrhage (PPH) is significant loss of blood following childbirth.
Loss >500mL of blood within the first 24 hours, in a vaginal delivery
Loss >1,000mL, in a Caesar
Some definitions worldwide also require hypovolemia, Sx, or even measure drops in hemoglobin [by 10%].
In short, what is PPH?
Loss of blood after giving birth, significant enough for us to be concerned. It's defined differently in vaginal delivery, and in Caesar. That's because Caesar is a surgical operation, so we permit more bleeding. Half a liter in vaginal deliveries. And 1 liter in Caesars. Anything greater than that is PPH.
So as a comparison, what proportion of blood is this to a normal woman?
In humans, it is around 5L, slightly less in women than men. Therefore, 500mL is around 10%, and 1L is around 20%.
Tachycardia → compensate for hypovolemia
Tachypnea → compensate for hypovolemia
Postural hypotension → due to hypovolemia
As more blood is lost:
Hypotension → due to hypovolemia
Decreased urination → due to hypovolemia
Feel cold → poor circulation to periphery
Become restless or unconscious → poor circulation to the brain
The condition can occur up to 6 weeks following delivery
What will happen to me if I have PPH ?
The sorts of things you'd expect when you have a big bleed. To compensate for low blood volume, your heart rate and breath rate goes up. Because blood volume is low, low blood pressure, decreased urination. And because you've got less blood going around your body, you might feel cold, become restless, or even unconscious.
The uterus maintains 33% of the cardiac output at term, so any compromise can cause large amounts of bleeding
Following delivery of the baby, the placenta separates from the uterus, leaving vessels that supplied the placenta [from the uterus] broke/ruptured. However, the myometrium (i.e. muscular layer of the uterine wall) contracts, constricting these blood vessels to cease bleeding. This occurs because the myometrium is arranged in a criss-cross pattern latticing around the blood vessels, so contraction causes clamping of the vessels, forming a clot to cease bleeding
Interruption of any of the aforementioned events can thus cause PPH, including (known as the 4 T's):
Atony of the uterus (77.5%, most common cause of PPH), which is poor contraction of the uterus following birth, usually due to distension of the uterus, and thus loss of tone in the uterine musculature. Normally, contraction of the uterine muscle compresses the vessels and reduces flow. This increases the likelihood of coagulation and prevents bleeds. Thus, lack of uterine muscle contraction can cause acute hemorrhage
Trauma to the birth canal (i.e. uterus, cervix, vagina, or perineum) (20%), which are more vascular during pregnancy, and so bleed more substantially, and more susceptible to laceration, and includes tears in the uterus
Tissue retention (10%), including retained placenta
Clotting disorder (1%), where there is a failure of clotting, such as in coagulopathies, or impairment due to drugs
What exactly causes PPH?
4 things, which we call the 4 T's, can cause problems with this. Tone, trauma, tissue retention, and thrombin.
Following delivery, blood vessels supplying the placenta from the uterus are broken. The uterus has to contract to constrict these vessels. If the uterus doesn't contract, these vessels don't constrict.
If there is trauma to the birth canal, there's going to be bleeding wherever that trauma is.
What's tissue retention?
If there's tissue retention, anything that's not supposed to be there is going to cause the body to say - that's not supposed to be there, and cause a problem.
Thrombin, that means blood clot, right?
Yep. And if the body has a problem clotting blood, the uterus-placental vessels are going to have problems ceasing to bleed.
Primary, which occurs within <24 hours of birth
Secondary, which occurs >24 hours after birth
Atony of the uterus:
Large baby → uterus distension
Multiple gestation → uterus distension
Polyhydramnios → uterus distension
Obese moms → weak muscles
>40yo moms → weak muscles
Prolonged labor → uterine fatigue
Use of oxytocin (per IOL/augmentation of labor)
Drugs (particularly magnesium)
Where drugs are used to induce labor
Trauma to the birth canal:
Episiotomy (i.e. incision to the perineum)
Following C sections → potential uterine rupture
Instrumental delivery (forceps/vacuum)
Congenital coagulopathies (hemophilia)
Placental abruption → DIC
HELLP → low platelets
Anemia → predisposition to blood disorder
Feel for a soft non-contracting uterus → uterine atony
Vaginal exam → trauma to the birth canal
Looking at the placenta, ensuring it is whole → tissue retention
FBC, coags (PT/INR) → coagulopathies
Hx coagulopathies → coagulopathies
What can you do to look into PPH further?
It depends if you suspect a particular type. To test for tone, you can try feeling for a soft uterus that isn't contracting. To test for trauma, you can do an internal examination through the vagina. To test for tissue retention, we look at the placenta and ensure that it is whole. To test for coagulopathy, you may be asked about coagulopathies you know you have, and even have blood tests testing your coagulation.
Prevention, involves decreasing known risk factors:
Uterine massage after delivery, which is compression of the uterus, to help assist uterine contraction. This can also be done bimanually (i.e. with the other hand inserted vaginally) → for uterine atony
Prophylactic uterotonic, preferably oxytocin 10 units IM, to stimulate the uterus to contract shortly after the baby is born → for uterine atony. Misoprostol can be used instead of oxytocin in resource poor settings
Controlled traction of the umbilical cord, whilst putting light pressure against the fundus [of the uterus], to help the placenta detach from the uterus → prevent retained tissue
It is incorrect that early clamping of the umbilical cord decreases risk, and may actually cause anemia, so is not usually recommended
Replete blood volume w/ IV fluids via large bore IV's, blood transfusion
Uterotonic agent (i.e. agent to help the uterus contract), e.g. ergotamine → for uterine atony
Compression of the aorta by pressing on the abdomen
Manual remove of retained tissue → retained tissue
Surgically repair lacerations → trauma
Blood transfusion of factors deficient in the Pt → for coagulopathies
Non-pneumatic anti-shock garment (i.e. low-tech first-aid device to Tx hypovolemic shock), to help until other measures (e.g. surgery) can be carried out
Hysterectomy, where all other options have been exhausted
Given how common PPH is - the fact that it occurs in 10% of pregnancies. What will my doctor do to prevent it?
To help prevent uterine atony, we massage the uterus to help it contract, and we give oxytocin to help stimulate the uterus to contract. To prevent retained tissue, we do controlled traction of the umbilical cord.
OK. All the preventative stuff was done . But I still got PPH . What now?
First things first. We make sure we have large bore IV access so we can give you IV fluids, and that you're oxygenated. Then, what you receive depends on what type you have. For uterine atony, we give you another drug to help the uterus contract. For retained tissue, we manually remove the retained tissue, which the practitioner will do by inserting their hand through your vagina, and pulling out retained tissue. For trauma, we will surgically repair lacerations. For coagulations, we will do a blood transfusion of factors deficient in the patient. So it depends a lot on the cause of PPH .
Source: 2010/pdf/PD2010_064.pdf">NSW Health (page 17)
It is a medical emergency
PPH is common, occurring in 10% of pregnancies globally
It is the 3rd top cause of maternal mortality, accounting for 25% of maternal deaths
Occurs in 2% of births
Whereas 0.4 per 100k deliveries die of PPH in the UK, whereas 150 per 100k deliveries die of PPH in sub-Saharan Africa
In the developing world, 3% of women with PPH die
Globally it results in 65k deaths annually, making it the leading cause of death during pregnancy
Practitioners tend to underestimate blood loss, so definition by volumetric loss may be inaccurate
Oxytocin reduces PPH by 40%
Rates of death have decreased substantially since at least the late 1800s in the West