Antrepartum Haemorrhage

Vaginal bleeding occurring from the 24th week of pregnancy and prior to the birth of the baby is termed antepartum haemorrhage (APH). There are a number of causes of bleeding in late pregnancy:

Placenta praevia

Placenta praevia occurs when the placenta is implanted wholly or in part into the lower segment of the uterus. If the cervical os is completely covered it is considered a major praevia (complete) and if not, then it is considered a minor praevia (marginal).

• The incidence is 0.48% with a resulting mortality of 0.03%. [14]
• The exact pathophysiology is unknown; uterine scarring (such as previous c-section), multiparity, multiple gestations and advanced maternal age are all associated risk factors.
• Bleeding is a result of contractions, cervical effacement and dilatation separating the placenta from the uterus.
• Prior to labour this may be self-limiting.
• Painless PV bleeding in the second or third trimester is the classical sign. However, abdominal pain can also occur. Placenta praevia may also be suspected later in pregnancy if the foetus is found to be in a breech or a transverse position.
• Antenatal screening at 20 weeks enables detection and expectant management.
• It is rare to have an undiagnosed placenta praevia present to the ED.
• Women who have had a bleed will be managed as in patients from 34 weeks. Asymptomatic women may be managed as outpatients with close monitoring. [15]

Placental abruption

Placental abruption is the complete or partial premature separation of a normally implanted placenta from the uterus causing haemorrhage.

• Bleeding may be concealed in up to 20% of placental abruption.
• Placental abruption should be considered when the pain is continuous. (Labour should also be considered if the pain is intermittent.)
• Abdominal examination may show fundal tenderness. A tense or ‘woody’ feel to the uterus indicates a significant abruption.
• Foetal distress is indicative of abruption and foetal death is common where separation is more than 50%. [16]
• DIC occurs in 10%, which can cause long-term renal failure.
• Increased maternal age, smoking, use of cocaine, hypertension, multiple pregnancy, high parity, prolonged rupture of membranes, low body mass index (BMI), pregnancy following assisted reproductive techniques, and trauma are all risk factors.

Vasa praevia

Vasa praevia is a condition in which the fetal blood vessels run freely and unsupported through the membranes, over the cervix across the internal os beneath the presenting part, unprotected by placenta or umbilical cord. [17]

• The incidence is approximately 1/2500 deliveries and undiagnosed is associated with a perinatal mortality of 56%. [17,18]
• Risk factors include placenta praevia, multilobed placenta, velamentous insertion of the umbilical cord, multiple pregnancies and IVF pregnancies.
• The fetal blood vessels may be ruptured at amniotomy, spontaneous rupture of membranes or during cervical dilatation.
• Painless PV bleeding and foetal heart activity abnormalities are common. Pulsating vessels on vaginal examination are indicative, however PV examination is normally contraindicated because of the possibility of placenta praevia.
• Targeted screening of high-risk pregnancies is suggested. [19]  Routine screening is not cost effective and undetected ‘low risk’ pregnancies may present to the ED.

Placenta accreta

Placenta accreta is abnormal adherence of the placenta to the uterus. It is strongly associated with previous caesarean sections and can be identified on US. It is usually a post partum phenomenon although rarely may cause spontaneous uterine rupture and massive intraperitoneal haemorrhage. [20]

Points to note:

• Vasa praevia and uterine rupture are rare
• placenta accreta is increasing in incidence with increasing caesarean section rate.
• No definite cause can be identified in at least half of cases of APH.

• Around 30% of domestic abuse begins during pregnancy, while 40 to 60% of women experiencing domestic abuse are abused during pregnancy. [21]
• While only one in five survivors of domestic violence will call the police, 80% will seek help from health services. [22]
• NICE recommends that all pregnant women should be asked about domestic violence as part of their social history. This is not limited to those who only present following trauma.
• It is therefore important in the emergency department we enquire about DV in a private and in a sensitive manner.