Introduction

Postpartum haemorrhage (PPH) is a serious condition that occurs after childbirth and is one of the leading causes of death among parents who have recently given birth worldwide.¹ This life-threatening condition affects about 3 to 5% of assigned female at birth (AFAB) people who give birth.² Most of these cases happen in low and middle-income countries, where around 2% of affected AFAB people die within 2 to 4 hours of experiencing severe bleeding. In addition to the immediate danger, approximately 11% of people with PPH will suffer from severe anaemia, a condition where the body doesn't have enough healthy red blood cells.³

PPH is defined as loss of blood after delivery; doctors also define the loss of  1000 mL associated with caesarean delivery or vaginal delivery plus signs and symptoms of hypovolemia.^1,4

Terminology

There are two types of postpartum haemorrhage according to the time of presentation:⁴

• Primary or early PPH: This type happens within the first 24 hours after delivery
• Secondary, late or delayed PPH: This type occurs more than 24 hours after delivery until 12 weeks postpartum

Pathophysiology

Near the end of pregnancy, the blood vessels in the uterus contain an incredible amount of blood. During childbirth and after the placenta separates, these vessels could be damaged, making it essential to stop bleeding quickly. The process of stopping the bleeding is called haemostasis and consists of three steps:¹  

• Mechanical haemostasis: Uterine muscles contract to reduce blood flow to the placenta. This mechanism can stop bleeding without the other mechanisms
• Local thrombosis: Blood clotting components promote the process of clotting in the damaged vessels that supply blood to the placenta.⁵ If there are lacerations in the uterus, birth canal or perineum, this step is essential in stopping the bleeding
• Obliteration of vessels: The final step involves completely closing off the blood vessels

If any of these steps do not work properly, bleeding can continue.

Risk factors

Several risk factors have been identified that increase the likelihood of haemorrhage, and the most notable of these are:⁶ 

• Placenta or membranes not coming out completely after the baby is born
• Labour not moving forward as it should during the pushing phase
• When the placenta grows too deeply into the wall of the uterus
• Tears in the vagina or surrounding tissues during childbirth
• Using tools to help deliver the baby vaginally such as forceps
• Giving birth to a very large baby (over 9 pounds)
• High blood pressure conditions like preeclampsia, eclampsia, and HELLP syndrome during pregnancy
• Medically inducing labour instead of waiting for it to begin on its own
• Labour takes a very long time in the early or pushing stages

Diagnosis

Diagnosing postpartum haemorrhage involves recognising significant blood loss and its symptoms. The key indicators are:

• Symptoms of hypovolemia (low blood volume) such as:^7,8
  • Palpitations
  • Light-headedness
  • Increased heart rate
  • Weakness
  • Sweating
  • Rapid heartbeat (tachycardia)
  • Rapid breathing (tachypnea)
  • Restlessness
  • Confusion
  • Pale skin (pallor)
  • Reduced urine output (oliguria)
• Blood loss: More than 1 litre of blood lost within 24 hours

Steps to prevent maternal death

During the diagnosis, it is vital to keep in mind the following steps to prevent maternal death:⁹

• Identify ongoing bleeding as soon as possible
• Quickly involve an experienced doctor
• Find out why the bleeding is happening early on. In this case, doctors usually look for:
  • Tears (lacerations) and bruises (hematomas)
  • Poor uterine muscle tone
  • Internal bleeding in the abdomen
  • Retained placental fragments or membranes (using ultrasound)
• Quickly check how much blood has been lost and if there are any blood clotting issues

Essential laboratory evaluation includes:¹⁰

• Complete blood count: Helps in the detection of anaemia
• Coagulation studies:
  • Fibrinogen level: Assesses blood clotting ability
  • Prothrombin time (PT): Measures how long it takes blood to clot
  • Activated partial thromboplastin time (aPTT): Checks for clotting problems
  • Type and screen or crossmatch: Determines blood type and checks for compatibility in case a transfusion is needed
  • Potassium and ionised calcium levels: Monitors essential minerals for proper body function
• Act quickly to stop the bleeding, which may include surgery, such as a hysterectomy, if other treatments fail

Aetiology 

Understanding the risk factors for postpartum haemorrhage is crucial for effective prevention and treatment. The main categories of risk factors are related to tone, trauma, tissue, and thrombin.²

Tone

Uterine atony is a problem where the uterus can’t contract and reduce its size after delivery. It is the most common cause of PPH, accounting for 80% of cases.¹¹ Identifying any risk factor that can predispose to uterine atony is essential for proper treatment. Some of these factors include:¹²

• Uterine overdistension: Conditions like multiple pregnancies, excess amniotic fluid (polyhydramnios), and large babies (foetal macrosomia) can cause this
• Labour-related factors: Induced labour, prolonged labour, very fast labour (precipitate labour), and manual removal of the placenta
• Use of uterine relaxants: e.g. deep anaesthesia and magnesium sulphate
• Intrinsic factors: Previous postpartum haemorrhage, bleeding before delivery (antepartum haemorrhage), obesity, and being over 35 years old

Trauma

Different types of trauma can lead to PPH, including:²

• Lacerations: Tears in the birth canal that can be controlled through haemostasis and timely repair
• Rupture: Tearing of the uterus
• Haematomas: Blood collection in the vagina or vulva area, causing pain or changes in vital signs that don't match the amount of visible blood loss. Treatment may include ice packs or surgical evacuation of the clot and ligation of bleeding vessels
• Inversion: The uterus turns inside out, a rare complication most often seen when the placenta invades the uterus

Tissue

Retained tissue prevents the uterus from contracting properly, leading to PPH. This can include:²

• Retained tissue: Pieces of the placenta or other tissues remain in the uterus
• Invasive placenta: The placenta grows too deeply into the uterine wall
• Blood clots: Clots remain in the uterus
• Placenta accreta spectrum: Includes conditions where the placenta attaches too deeply into the uterine wall

Thrombin (coagulation defects)

Coagulopathy, or blood clotting problems, should be suspected if the patient does not respond to the usual treatments and presents with haematomas or bleeding from puncture sites.²

Treatment

Treating postpartum haemorrhage focuses on stabilising the patient while identifying and addressing the cause of the bleeding. Here are the key steps: ^2,13,14

Initial care

• Start by giving fluids to support blood circulation
• If bleeding is severe, switch to blood transfusions and administer tranexamic acid early to reduce the risk of death from bleeding.

Specific treatments based on cause

• Uterine atony: When the uterus fails to contract, doctors use medications to help it contract. If the birth was a caesarean, further treatment is more accessible because the abdomen is already open
• Lacerations: Tears are treated with surgery
• Blood clotting problems: These are treated with blood transfusions and particular medications.

Care for unstable patients

• Initial care: Begin treatment in the best area for resuscitation and emergency surgery
• Blood transfusion: Administer a blood transfusion as soon as possible
• Severe blood clotting issues: Use cryoprecipitate or other high-fibrinogen products to correct clotting problems
• Stabilising measures: Implement temporary measures to help patients tolerate general anaesthesia and surgery if needed
• Early hysterectomy: Consider an early hysterectomy if other treatments fail
• Ongoing management: Continue treating patients with ongoing bleeding in an operating room rather than an intensive care unit (ICU)

Complications

Postpartum haemorrhage can lead to severe complications, both short-term and long-term, including death, immediate health issues, and chronic conditions.

Short-term morbidity

Anaemia

Postpartum anaemia is defined as a decrease in red blood cells of less than 11 g/dL at one week postpartum and less than 12 g/dL at eight weeks postpartum.¹⁵ It is more frequent in those who experienced iron deficiency near the delivery date.¹⁵

Hysterectomy

A hysterectomy is the surgical removal of the uterus, sometimes including the ovaries. This is an infrequent treatment due to their aggressive approach, and it is used as the last option for treatment for bleeding during uterine atony (lack of muscle tone), surgical trauma or abnormal placentation.¹⁶

Organ damage

Severe blood loss reduces blood flow to various organs, causing them to fail.. This can lead to kidney failure, heart failure, respiratory failure or hepatic failure.¹⁷

Thromboembolism

Thromboembolism is when a blood clot forms in a blood vessel (a thrombus) and then travels to another part of the body (an embolus), causing a blockage. It is infrequent, being found in 0.3% of patients with PPH.

Long-term morbidity

Sheehan syndrome

A large amount of blood loss results in pituitary gland damage. Symptoms often occur after childbirth and include fatigue, inability to produce breast milk, low blood pressure, and weight loss. It is diagnosed through blood tests for hormone levels and imaging tests like MRI. Treatment involves hormone replacement therapy.^18,19

Asherman syndrome

Asherman syndrome is the reduction of absent menstruation secondary to trauma in the uterine cavity that generates intrauterine or endocervix adhesions. Clinically, it seems as low or no menstruation, reduced fertility, pregnancy loss and abnormal placentation. Diagnosis is done using hysteroscopy, ultrasound, or MRI. Treatment typically involves surgery to remove the scar tissue, followed by hormone therapy to help the uterine lining heal.²⁰

Conclusion

Postpartum haemorrhage (PPH) is a significant and life-threatening condition affecting new AFAB parents globally. It remains a leading cause of maternal mortality, particularly in low and middle-income countries. PPH can lead to severe complications such as anaemia, organ failure, and thromboembolism, as well as long-term conditions like Sheehan syndrome and Asherman syndrome.

Effective management and timely intervention are crucial in reducing the risks associated with PPH. Key steps in treatment include identifying and addressing the underlying causes, such as uterine atony, trauma during childbirth, retained tissue, and blood clotting disorders. Early recognition of symptoms, prompt involvement of experienced healthcare professionals, and appropriate medical and surgical interventions can significantly improve outcomes for affected people.

Understanding PPH's risk factors and pathophysiology helps in its prevention and management. Healthcare providers should be vigilant in identifying high-risk patients and take proactive measures to ensure the safety and well-being of new parents during and after childbirth. With improved awareness, timely diagnosis, and effective treatment strategies, the impact of PPH can be mitigated, thereby saving lives and reducing morbidity.