Antepartum haemorrhage

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Chapter 32 Antepartum haemorrhage

Michael Flynn

Definition. Antepartum haemorrhage is bleeding from the genital tract in the period from 20 weeks gestation to the birth of the baby.

Incidence. It occurs in 3% of pregnancies of >28 weeks gestation and 5% of pregnancies of >20 weeks gestation.

Aetiology

• placenta praevia
• placental abruption
• marginal bleed
• vasa praevia
• uterine rupture
• local causes: cervix, vagina

The source is almost entirely maternal in origin.

Placenta praevia

Incidence. Incidence is about 1%, rising with frequency of previous caesarean section.

Presentation. The placenta is attached to the lower segment of the uterus and/or covering the cervix. The presentation is usually that of a painless antepartum haemorrhage with a high presenting part. The absence of contractions and pain makes diagnosis more likely.

Routine second-trimester ultrasound will diagnose low-lying and placenta praevia.

Classification

• complete or grade 4 placenta praevia where placenta completely centrally covers the os
• marginal or grade 3 placenta praevia where the os is covered by the placenta edge
• marginal or grade 1 and 2 where the placenta is near but does not cover the os

The diagnosis is usually made in the third trimester. At the second trimester morphology assessment, a low-grade placenta praevia will be termed a ‘low lying placenta’ for complete assessment in the third trimester. Diagnosis of normal placental site is >5 cm from the cervical os.

Risk factors

• increased number of caesarean sections
• increased parity

Management

If asymptomatic and diagnosed at morphology scan, management is confirmation of diagnosis in the third trimester and planning elective caesarean section.

• It may involve resuscitation of the mother, fetal assessment and delivery (dependent on the amount of bleeding, continuation of bleeding and fetal maturity).
• Pregnancy may need to be prolonged to decrease prematurity and lower perinatal mortality.
• Insert intravenous line, and cross-match for blood.
• Confirm the diagnosis with an ultrasound scan.
• Use expectant management if preterm and the blood loss is small.
• Order serial growth scans to exclude intrauterine growth restriction (IUGR).
• Admit the patient and plan for her to remain in hospital until delivery by caesarean section if it is a major grade praevia.
• Use steroid prophylaxis for lung maturity if the fetus is premature.
• Iron supplementation is useful.
• Use anti-D prophylaxis if the mother is Rhesus D-negative.
• Perform caesarean section if a large bleed has occurred and is continuing.
• Watch for postpartum haemorrhage, and counsel regarding possible hysterectomy.
• Avoid digital examination and intercourse in the third trimester.

Placenta percreta

Invasion of the placenta to within the myometrium should be suspected in previous cases of placenta praevia. This is especially so in the case of placenta praevia and previous caesarean section where the rate of placenta acreta is 5%. As there is a significant risk of major haemorrhage, delivery via caesarean section should be well planned with blood products available and counselling of the possibility of hysterectomy.

Placental abruption

Incidence. Incidence is 1%.

Definition. Abruption is haemorrhage from decidual detachment of a normally situated placenta. The woman presents with abdominal pain, tense and tender uterus, which is large for dates, and hypovolaemic shock that may be out of proportion with visible bleeding.

Risk factors

• hypertension
• increased parity
• poor nutrition
• previous abruption (after one abruption the recurrence risk is 5%–15% and after two the risk is 25%)
• trauma, external cephalic version
• sudden reduction in uterine volume (e.g. after delivery of the first twin)

Differential diagnosis

• placenta praevia
• uterine rupture
• degeneration of fibroid
• rectus sheath haematoma
• acute polyhydramnios
• acute surgical conditions

Complications of placental abruption

• coagulopathy (abruption is the commonest obstetric cause of coagulopathy: 10% of abruptions demonstrate significant changes in coagulation profiles; there is a reduction in platelets and fibrinogen, increased fibrin degradation products and prothrombin time; fibrin degradation products inhibit myometrial activity, increase the risk of postpartum haemorrhage and may have cardiotoxic effects)
• postpartum haemorrhage
• renal failure
• acute tubular necrosis from hypovolaemia and disseminated intravascular coagulopathy
• perinatal mortality of 119 in 1000 births complicated by abruption

Management

• Resuscitate and restore circulatory volume to prevent renal shutdown and to clear fibrin degradation products.
• Cross-match for blood and, if indicated, platelets and fresh frozen plasma. Check full blood count, coagulation profile, renal function and electrolytes and liver biochemistry.
• Monitor urine output.
• Perform fetal assessment and delivery.

Vasa praevia

This is associated with the rupture of fetal vessels. It is often associated with velamentous insertion of the cord, with vessels present within the fetal membranes.

Diagnosis

Vasa praevia must be included in the differential diagnosis of intrapartum vaginal bleeding, and is associated with an ominous cardiotocography pattern. Diagnosis can occur in the antenatal period with transvaginal ultrasound and colour Doppler assessment of vessels across the top of the cervical os. In the presence of blood loss and ominous fetal heart rate, although theoretical tests (Apts) are available, vasa praevia may result in fetal anaemia and death. Hence, emergency delivery is indicated.

Local causes

These include cervicitis, polyps, ectropion and cervical cancer.

Further reading

Morgan K., Arulkumaran S. Antepartum haemorrhage. Current Opinion in Obstetrics and Gynaecology. 2003;13:81-87.

Scott J.C. Antepartum haemorrhage. In: Whitfield C.R., editor. Dewhurst’s textbook of obstetrics and gynaecology for postgraduates.. Oxford: Blackwell Scientific Publishers, 1988.

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Chapter 32 Antepartum haemorrhage

Michael Flynn

Definition. Antepartum haemorrhage is bleeding from the genital tract in the period from 20 weeks gestation to the birth of the baby.

Incidence. It occurs in 3% of pregnancies of >28 weeks gestation and 5% of pregnancies of >20 weeks gestation.

Aetiology

• placenta praevia
• placental abruption
• marginal bleed
• vasa praevia
• uterine rupture
• local causes: cervix, vagina

The source is almost entirely maternal in origin.

Placenta praevia

Incidence. Incidence is about 1%, rising with frequency of previous caesarean section.

Presentation. The placenta is attached to the lower segment of the uterus and/or covering the cervix. The presentation is usually that of a painless antepartum haemorrhage with a high presenting part. The absence of contractions and pain makes diagnosis more likely.

Routine second-trimester ultrasound will diagnose low-lying and placenta praevia.

Classification

• complete or grade 4 placenta praevia where placenta completely centrally covers the os
• marginal or grade 3 placenta praevia where the os is covered by the placenta edge
• marginal or grade 1 and 2 where the placenta is near but does not cover the os

The diagnosis is usually made in the third trimester. At the second trimester morphology assessment, a low-grade placenta praevia will be termed a ‘low lying placenta’ for complete assessment in the third trimester. Diagnosis of normal placental site is >5 cm from the cervical os.

Risk factors

• increased number of caesarean sections
• increased parity

Management

If asymptomatic and diagnosed at morphology scan, management is confirmation of diagnosis in the third trimester and planning elective caesarean section.

• It may involve resuscitation of the mother, fetal assessment and delivery (dependent on the amount of bleeding, continuation of bleeding and fetal maturity).
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