Placental abruption
Placenta praevia
Vasa praevia
Marginal bleed
Uterine rupture
Cervical bleeding
ectropion
cervicitis
polyp
neoplasm
Vaginal bleeding
trauma
neoplasm
GI bleeding
haemorrhoids
inflammatory bowel
Urinary tract
infection
There are no consistent classifications for the severity of APH. The following definitions are widely used:1
Spotting – staining, streaking or blood spotting noted on underwear or sanitary protection
Minor haemorrhage – blood loss < 50 mL that has settled
Major haemorrhage – blood loss of 50–1000 mL, with no signs of shock
Massive haemorrhage – blood loss greater than 1000 mL and/or signs of clinical shock
The amount of blood loss is frequently underestimated. The mother’s general condition, and in particular signs of shock, can help to determine the severity of the bleeding. Fetal distress or demise is a good indicator of significant volume depletion.
General management principles
The basic principles of resuscitation should be followed in a woman presenting with major APH or collapse. This should include a primary survey with a structured approach for checking the airways, breathing and circulation (‘ABC’). Following this, causes should be considered and specific management tailored to this.
Abdominal palpation should be performed. A soft, non-tender uterus may suggest placenta praevia or local causes. On the other hand, a tender hard uterus would be more in keeping with placental abruption. Speculum examination is helpful to assess for vaginal or cervical causes and may reveal cervical dilatation. Digital vaginal examination should not be performed until placenta praevia has been excluded.
All RhD-negative women should have a Kleihauer test performed to quantify fetomaternal haemorrhage. Anti-D immunoglobulin must be given to all non-sensitized RhD-negative women after any presentation of APH. In minor haemorrhage, a full blood count (FBC) and group and save should be requested. In major APH, in addition to FBC, blood should be obtained for clotting screen, renal and liver function, and four units of red cells crossmatched. Clotting factors including platelets, fresh frozen plasma (FFP) and cryoprecipitate are likely to be required if more than 4–6 units of blood are transfused.
Once resuscitation has commenced and/or the mother is stable, fetal assessment with a cardiotocograph (CTG) should be performed. This may influence the timing and mode of delivery. If the fetal heart cannot be auscultated, an ultrasound scan is indicated to exclude an intrauterine fetal death.
If there is maternal and/or fetal compromise, an obstetric emergency should be declared. Immediate delivery is recommended once resuscitation of the mother has been commenced. In situations where there is fetal distress, the priority is to stabilize the mother, while preparing to deliver the fetus. Delivery is usually by caesarean section in these circumstances, unless the woman is in established labour, there are no contraindications and vaginal delivery is imminent. If fetal death is diagnosed, vaginal birth is recommended, but caesarean section may be indicated in some cases.
Placental abruption
Placental abruption is the premature separation of a normally implanted placenta from the uterine wall, resulting in haemorrhage before the delivery of the fetus. In severe cases, it is associated with significant perinatal morbidity and mortality. The severity of fetal distress correlates with the degree of placental separation. In near-complete or complete abruption, fetal death is inevitable, unless there is immediate delivery. Although maternal mortality is rare, morbidity can result from haemorrhage, shock, disseminated intravascular coagulation (DIC) and renal failure.
Pathophysiology
This is usually of a normally sited placenta but can also occur in relation to a low-lying placenta. Abruption arises from bleeding into the decidua basalis, which results in the formation of a haematoma and subsequent increase in hydrostatic pressure. This in turn leads to a separation of the adjacent placenta. In its pregnant, distended state the uterus is unable to contract around the uterine vessels at the placental site, so the bleeding persists. The expanding clot can dissect between the fetal membranes and present as vaginal bleeding or remain confined within the uterus and behind the placenta. The amount of visible bleeding is therefore a poor reflection of the actual extent of blood loss. The placental separation can be partial and self-limiting or complete, leading to the potentially devastating consequences of catastrophic bleeding and fetal demise. Damage to the fetus results from decreased placental perfusion, caused by the clot forming a barrier between the placental bed and the villi, in addition to the release of prostaglandins, which cause uterine spasm.
Occasionally, and particularly with concealed abruption, there may be bleeding into the muscles and blood vessels of the uterus, causing injury and damage. Blood can leak out of the damaged vessels and collect in the uterine muscles, causing oedema and necrosis. It is the infiltration of blood into the myometrium that is associated with pain and sustained uterine contraction, making the uterus feel ‘woody’ on examination. This is also responsible for provoking labour and reducing uteroplacental flow. Abruptions are painful and, in contrast to labour, the pain can be constant.
Minute bruises and ecchymoses may appear on the surface of the uterus causing it to look blotchy-blue. This is known as Couvelaire uterus, a rare but serious consequence of abruption.
Aetiology
While there are several risk factors associated with placental abruption, causal pathways remain speculative. The most predictive risk is abruption in a previous pregnancy. The recurrence rate in subsequent pregnancies is 7–9%, which increases to 19–25% in those women who have had two previous pregnancies complicated by abruption.
First-trimester bleeding increases the risk of abruption later in the pregnancy. Women with ultrasound-detected subchorionic haemorrhage before 22 weeks of gestation have been found to be at increased risk of placental abruption and preterm delivery but are not at increased risk of other adverse pregnancy outcomes.2
Some disorders characterized by thrombophilia have also been implicated in the past, particularly factor V Leiden and prothrombin gene mutation; however, the association is weak.
In view of the known links with tobacco, cocaine and amphetamines, women should be encouraged to abstain from these. Table 2.2 summarizes the risk factors for placental abruption.
| Maternal | Obstetric/fetal | Other |
|---|---|---|
| Previous abruption Advanced maternal age Multiparity Low body mass index (BMI) Smoking and drug misuse (tobacco, cocaine and amphetamines) Hypertension | Fetal growth restriction Polyhydramnios Pre-eclampsia Non-vertex presentations Intrauterine infection Premature rupture of membranes | Abdominal trauma |
Clinical presentation
The diagnosis of abruption is made on the basis of clinical presentation. Ultrasound imaging of the placenta is of limited diagnostic value except in cases of large retroplacental haematoma, where the positive predictive value is high. In severe cases, there may be heavy vaginal bleeding and acute abdominal pain. Serous fluid from a retroplacental haematoma may trickle out and be confused with amniotic fluid. 50% of patients will present in labour, and rupturing the membranes may demonstrate blood-stained liquor. Classically, the uterus is tender and tense, often described as ‘woody hard’. There may be uterine irritability and palpable contractions or hypertonus, resulting in labour. Fetal distress or intrauterine fetal death may be diagnosed. The woman may be in hypovolaemic shock. However, sometimes the diagnosis of abruption is not so obvious, particularly when the symptoms and signs are more subtle.
Broadly speaking, there are three types of placental abruption:
Revealed – The bleeding flows down between the membranes and the uterine wall and is revealed at the introitus. Since there is little or no collection of blood behind the placenta, separation from the uterus is usually less than in the other types.
Concealed – The blood collects between the placenta and the uterine wall and fails to trickle out of the vagina. The extent of bleeding is therefore frequently underestimated. Blood clot can continue to dissect the placenta from its uterine bed and separate over large areas, sometime completely. This is typically the severe type of abruption.
Mixed – This presents with bleeding but there is also concealed bleeding behind the placenta. This should be suspected when the degree of compromise is out of proportion to the bleeding.
The severity of placental abruption can be classified based on various clinical features. This is shown in Table 2.3.
| Class | Incidence | Features/characteristics |
|---|---|---|
| Class 0 – asymptomatic | Made retrospectively by finding an organized clot or depressed area in the placenta | |
| Class 1 – mild | 48% | No/minimal vaginal bleeding No maternal or fetal compromise |
| Class 2 – moderate | 27% | No/moderate vaginal bleeding Moderate uterine tenderness Maternal tachycardia, orthostatic changes in BP and heart rate Fetal distress |
| Class 3 – severe | 24% | No/heavy vaginal bleeding Very painful hypertonic contractions Maternal shock Coagulopathy Fetal death |
Management
In mild placental abruption, the bleeding may settle and the symptoms gradually resolve. With satisfactory fetal monitoring these women can often be managed as outpatients. It is not always possible to distinguish between idiopathic preterm labour and mild abruption, and thus these women should have continuous electronic fetal monitoring and careful observation.
The management goals in moderate or severe placental abruption are to correct the hypovolaemia, deliver the fetus and observe for and correct any coagulation defect that arises. This requires management in the labour ward, with intensive monitoring of both mother and fetus.
The management of severe abruption requires a multidisciplinary team approach, and the protocol for massive APH should be implemented. Initial management should follow the ABC pathway for resuscitation. Two large-bore intravenous lines are required and blood should be sent urgently, including a crossmatch of four units. An indwelling catheter should be inserted. As the woman is being stabilized, the fetus can be assessed and a plan made for delivery.
Resuscitation and caesarean section/induction of labour can happen simultaneously, and in the event of fetal distress delivery should be undertaken without delay. Placental abruption often precipitates rapid labour, and vaginal delivery may be possible in the absence of fetal distress. Artificial rupture of the membranes should be performed to expedite labour.
The aim of resuscitation is to achieve safe delivery of the fetus and to enter the third stage of labour with a normal blood pressure (BP), central venous pressure (CVP) and urine output, and corrected DIC.
As per Royal College of Obstetricians and Gynaecologists (RCOG) guidance, there are four pillars of management:
1. communication between all members of the multidisciplinary team
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
