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INTRODUCTION
Postpartum haemorrhage (PPH) is classified into primary and secondary. Primary PPH is defined as blood loss more than 500ml within 24 hours after vaginal delivery or 1000ml or more for a Caesarean section. Secondary PPH is any such bleeding occurring after 24 hours. Primary PPH accounts for a larger percentage of the maternal morbidity and mortality from PPH.

PPH accounts for approximately 25% of maternal deaths worldwide and more than half of maternal deaths in Africa and Southeast Asia.
This write-up will focus mainly on primary PPH.

The risk factors for PPH include:
-prolonged third stage of labour (ie. Delay in the delivery of the placenta),
-multiple delivery (twins, triplet, etc),
-fetal macrosomia (above 4- 4.5kg birth weight) ,
-‎induced labour,
-prolonged labour,
-‎precipitate labour (labour and delivery lasting 3 hours or less),
-‎episiotomy,
-‎previous history of PPH,
-advanced maternal age (above 40),
-‎grand multiparity (4 or more previous deliveries),
-abnormal placenta (eg. Placenta previa),
-‎previous Caeserean sections,
-‎previous uterine surgery (eg. Myomectomy),
-‎anaemia in current pregnancy
-history of bleeding disorders – congenital or iatrogenic

CAUSES OF PPH
This can be summarized under the “4T’s”

1. TONE – Atony refers to inability of the uterus to contract following the birth of the baby and placenta. The uterus is supplied with a huge amount of blood during pregnancy and labour. After the delivery, the uterine muscles should contract so that this blood will flow back into the body for redistribution. Failure to contract, results in bleeding from the vagina, which can easily lead to death in the absence of quick intervention.

2. TRAUMA – Trauma can occur during vaginal or Caesarean delivery at any level of the genital tract, up to the uterus and its supporting structures. This can cause heavy bleeding, which can be apparent or hidden (internal bleeding)

3. TISSUE – Incomplete delivery of the placenta and membranes can trigger a cascade of events which only gets worse unless the retained tissue is removed. Even an inch of placenta remnant is enough to cause torrential bleeding.

4. THROMBIN – The body is designed to stop bleeding by itself. This process is mediated by certain substances collectively known as the coagulation or clotting factors. With moderate bleeding, these factors come into play and stop the bleeding. When bleeding exceeds a certain threshold, the factors are “consumed” and bleeding continues unless there is medical intervention.

MANAGEMENT OF PPH
Healthy women usually “compensate” well for moderate blood loss. Therefore, there may be no obvious signs and symptoms until a woman has had massive bleeding. Common signs/symptoms of PPH include sudden collapse, dizziness, paleness, low urine output, distended abdomen, high heart rate and low blood pressure.

The management of postpartum haemorrhage revolves around 4 major strategies which are primarily preventive:

1. Active management of the third stage of labour– this involves the administration of a uterotonic agent (such as oxytocin +/- ergometrine) with controlled traction of the umbilical cord

2. ‎Use of uterotonic agents, such as oxytocin, misoprostol, carboprost and tranexamic acid

3. ‎Early and accurate blood loss estimation – this is essential to ensure prompt intervention and appropriate blood replacement.

4. ‎Compression techniques – includes internal or external manual compression, use of anti-shock garment, mechanical tamponade using specialized catheter/balloon devices, and surgical compression techniques (such as B-Lynch sutures)

Definitive management of PPH includes quick RESUSCITATION and aggressive SPECIFIC (MEDICAL/SURGICAL) INTERVENTIONS.

RESUSCITATION involves :
-Intravenous fluids
-Oxygen therapy
-Transfusion of blood and blood products
-Infusion of specific clotting factors
-‎Close monitoring of vital signs, urine output +/- intensive care admission
-Laboratory investigations: to determine the extent and effects of blood loss, and monitor the progress and response to treatment (haematocrit, coagulation profile, blood grouping and crossmatch, etc.)
-A multidisciplinary team which includes a senior obstetrician, haematologist, and anesthetist.

MEDICAL/SURGICAL INTERVENTIONS include:
-Medications – such as uterotonics (see above) and tranexamic acid
-Expeditious repair of episiotomy +/- lacerations in the lower genital tract
-‎Exploration of the upper genital tract under anesthesia
-Exploratory laparotomy (opening the abdomen) and Ligation of bleeding vessels.
-Interventional radiology (Arterial embolization)
-‎Hysterectomy (removal of the uterus +/- cervix)

CONCLUSION
PPH is a preventable cause of maternal death but it remains prevalent in the developing world due to poverty, ignorance, unnecessary delays in medical intervention and inadequate medical infrastructure. The burden of morbidity and mortality from PPH can be reduced by:
-adequate funding and improving the quality of maternal health services,
-community sensitization and education,
-expert supervision of pregnancy/labour in high risk groups,
-active management of the third stage of labour.

Reference : Postpartum Haemorrhage in the Developing World A Review of Clinical Management Strategies, John W. Snelgrove, MD
McGill Journal of Medicine (MJM)