Overview

What is placental abruption?

Placental abruption occurs when your placenta separates prematurely from the uterus before the end of the second stage of labour (when the cervix is fully dilated until the baby has been delivered). The separation of the placenta prematurely from the uterus occurs when the blood vessels that connect the uterine lining and the maternal side of the placenta become torn away. This can have consequences for your unborn child as the blood vessels in the placenta allow oxygen and nutrients to travel from mother to baby via the umbilical cord.^1,2

Whilst being a serious condition, placental abruption is relatively rare and occurs before 37 weeks gestation.¹

Why is it important to understand the causes and symptoms of placental abruption?

Understanding the causes and symptoms of placental abruption, and being able to identify any symptoms can ensure that you receive the healthcare that you and your baby require. This is important as placental abruption carries a risk for both you and your baby. For example, placental abruption can result in preterm birth, low birth weight, and very sadly stillborn birth. For the mother, you may also suffer from a haemorrhage and may require blood transfusions.¹

Causes of placental abruption

Maternal factors

Hypertension

If you have hypertension prior to becoming pregnant, this can increase your chance of developing a placental syndrome, such as placental abruption.³ In addition, pregnancy-induced hypertension may increase your risk of having placental abruption. Placental-induced hypertension is a form of hypertension that begins after the 20^th week of gestation.⁴

Trauma

 placental abruption may also be caused by blunt trauma to the mother’s abdomen, which has been observed in a case study where a 21-year-old woman was sadly in a motor vehicle accident at 17 weeks gestation.⁵ However, the symptoms of placental abruption may not be as easily recognised, as this can occur without the mother suffering from severe vaginal bleeding and without regular uterine contractions.⁵

Advanced maternal age

Studies have found that mothers over 35 years of age are at a higher risk of developing placental abruption.¹ It has been suggested that the association between placental abruption and increasing maternal age is caused by less vascularization of the uterus, which occurs as the mother becomes older. Less vascularization of the uterus means that there are less blood vessels providing oxygen and nutrients to the uterus.⁶

Placental factors

Placenta previa

Placenta previa is when the placenta either partially or completely blocks the cervix, which is the neck of the uterus.⁷ Placenta previa is a risk factor for developing placental abruption, with 5% of expectant mothers who have developed placenta previa going on to develop placental abruption.⁸

Placental insufficiency

Placental insufficiency results in your unborn child not receiving enough oxygen and nutrients from you via the placenta.⁹ Placental insufficiency has been considered as one of the key mechanisms responsible for placental abruption.¹⁰

Multiple pregnancies

Twin pregnancies, and carrying multiple babies, carry a higher risk of placental abruption than if you were carrying just one baby.¹¹

Lifestyle factors

Substance abuse

If the mother uses stimulants, such as cocaine, amphetamine or methamphetamine, whilst pregnant this can increase the risk of placental abruption occurring. Abusing these substances can also be catastrophic for your baby resulting in possible foetal death. For the mother, abusing these substances can result in malnutrition and hypertension, which is another risk factor for placental abruption.^12,3

Smoking

One study has found that cigarette smoking increased the risk of placental abruption occurring, but alcohol consumption did not increase this risk. However, both cigarette smoking and drinking alcohol increased the risk of placental abruption occurring more than smoking alone did.¹³

Poor nutrition

A lack of folic acid has been linked to an increased risk of placental abruption. In studies conducted in India, vitamin B12 deficiency was also associated with a higher risk of placental abruption. ¹⁴

Symptoms of placental abruption

Vaginal bleeding

Vaginal bleeding is a symptom of placental abruption, occurring in approximately 35-80% of placental abruption cases.¹⁵ In some cases, There is a possibility that blood may be trapped in the uterus if you have a placental abruption so there may not be any vaginal bleeding. However, this does not mean that you are not suffering from placental abruption. There are also some instances where placental abruption develops slowly, which in turn can cause light and irregular vaginal bleeding. It is also important to note that the amount of bleeding experienced does not mean that more of the placenta has separated from the wall of the womb (the uterus).

Abdominal pain

Abdominal pain is one of the most common symptoms of placental abruption, occurring in approximately 70% of cases.¹⁵ Abdominal pain, in conjunction with back pain, usually begins suddenly, with the pain being described as quite intense.¹

Uterine tenderness

Uterine tenderness is prevalent in approximately 75% of cases of placental abruption.¹⁵ Significant uterine tenderness is associated with more severe cases of placental abruption. In addition, in more severe cases of placental abruption, the uterus can feel more rigid.¹

Contractions

Uterine contractions are prevalent in approximately 75% of cases of placental abruption.¹⁵ Uterine contractions tend to come one after the other due to placental abruption. Similar to uterine tenderness, more tetanic uterine contractions can indicate a more severe form of placental abruption. ¹

Foetal distress

Foetal distress can indicate a more severe form of placental abruption.¹ Foetal distress is when your baby is not receiving enough oxygen in the womb. During foetal distress, your baby’s heart rate will begin to slow down in response to contractions but does not increase again as it should.

Hypovolemic shock

Bleeding caused by placental abruption may cause the mother to go into hypovolemic shock.⁸ Hypovolemic shock is potentially life-threatening and can cause circulatory failure, due to there being a severe loss of blood. If left untreated, body tissues may become starved of oxygen, which is needed for their survival, and this may escalate, resulting in organ failure and potential death.¹⁶

Diagnosis and treatment

Diagnostic methods

Physical examination

Physical examination of the patient is useful when diagnosing placental abruption to see if there is any physical manifestation of the symptoms of placental abruption. During the physical examination of the uterus, the uterus will be examined for any tenderness and consistency. This examination will also allow the frequency and duration of any uterine contractions to be determined. The vaginal area will also be examined to see if there is any bleeding present. You may also be assessed to see if you have any signs of tachycardia (increased heart rate) or hypotension (low blood pressure), as these could indicate that you (the mother) are having a haemorrhage. ¹

Ultrasound

If some of the symptoms of placental abruption are present, a healthcare provider may take an ultrasound of your uterus, which uses high-frequency sound waves to visualise your uterus and help diagnose placental abruption. However, it is worth noting that placental abruption can not always be identified via ultrasound. (Mayo Clinic) Usually, placental abruption is diagnosed after physical examination, and observing the manifestation of clinical symptoms, with an ultrasound confirming the diagnosis.¹⁷

Foetal monitoring

Continuous electronic foetal monitoring occurs if there is suspected placental abruption. The foetus’ heart rate will be monitored, any drop in heart rate (bradycardia), may indicate that placental abruption has occurred. In addition, foetal monitoring will also allow any decrease in foetal movements to be observed. This will indicate that the placenta is not well perfused, meaning that the foetus is not receiving enough oxygen and nutrients due to a lack of blood supply from the mother. This in turn can cause the foetus to move less and conserve their energy.¹⁸

It is important to note that a definitive diagnosis of placental abruption can only be made after the placenta itself has been examined by a healthcare professional.¹

Treatment options

Hospitalisation

Due to the onset of placental abruption being very sudden, unexpected and intense medical intervention is required immediately, which includes hospitalisation. This ensures that the outcome is the best for mother and baby. Hospitalisation allows there to be continuous monitoring of both mother and baby, and if there are any signs of foetal distress this allows an emergency caesarean section ( C-section) to be carried out promptly to give the baby the best chance of survival.¹

Blood transfusion

With a placental abruption, the mother is at a risk of haemorrhage (severe blood loss), and may require a blood transfusion as a treatment to save her life.¹

Emergency caesarean delivery

An emergency C-section can prevent foetal distress and possible foetal demise.¹ In addition, an emergency C-section can be crucial for the mother too, helping to prevent maternal death.¹⁹

Prevention strategies

Managing risk factors

You can manage risk factors to decrease the chance of placental abruption occurring. For example, interventions which prevent high blood pressure may in turn reduce the risk of placental abruption.²⁰

Lifestyle modifications

Avoiding smoking whilst pregnant and substance abuse, such as the use of cocaine can again minimise your risk of placental abruption occurring.^12,13

Summary

• Placental abruption occurs when the placenta detaches from the uterus and can be a serious condition for both mother and baby
• Placental abruption can result in preterm birth, low birth weight and sadly stillborn birth
• Maternal causes of placental abruption include maternal hypertension, trauma, advanced maternal age (over age 35)
• Placenta causes of placental abruption include placenta previa, placental insufficiency, and multiple pregnancies
• Lifestyle causes of placental abruption include substance abuse (stimulants such as cocaine), maternal malnourishment, and smoking
• Symptoms of placental abruption include vaginal bleeding, uterus tenderness and contractions, foetal distress, hypovolemic shock to the mother, and abdominal pain
• Diagnosis of placental abruption is done via examination of the mother, including her uterus and seeing if there is any vaginal bleeding, and an ultrasound may confirm this
• Foetal monitoring may be used as a tool to help diagnose placental abruption
• Placental abruption’s risk factors can be managed to reduce the risk of this occurring, and avoiding smoking and substance abuse can also minimise the risk