Placental Abruption

Question 1

Definition of placental abruption

Answer 1

Premature separation of the placenta from the wall of the uterus during pregnancy. The site of attachment can bleed extensively after this separation. The lower limit of gestational age has decreased over time from 28 weeks to 20 weeks. Incidence: Around 1 in 200 pregnancies.

Question 2

Risk factors for placental abruption

Answer 2

• Abruption in a previous pregnancy (4.4% incidence of recurrent abruption)
• Abdominal trauma (Both accidental and resulting from domestic violence)
• Maternal factors: Smoking, cocaine or amphetamine use, Increased maternal age, multiparity, lower BMI, thrombophilias
• Complications in pregnancy: PET, FGR, Non-vertex presentations, polyhydramnios, multiple pregnancies, IVF, PPROM, intrauterine infections
• Approximately 70% of cases of placental abruption occur in low risk pregnancies

Question 3

Pathophysiology of placental abruption

Answer 3

The precise aetiology of placental abruption is unknown, but may result from direct trauma causing mechanical separation, indirect shearing of the placenta, or vasospasm resulting in separation (factors such as cocaine use)
* Bleeding begins in the decidua basalis and leads to seperation of the placenta from the uterine wall
* If there Is large pressure generated from the uterus, the blood can then extend into the myometrium, which can become weakened and may rupture during contractions

Question 4

Complications of placental abruption

Answer 4

Short term- DIC, hypovolaemia, anaemia, PPH.
Long term- IUGR, neurological impairment of the infant, perinatal death, acute renal failure

Question 5

Classification of antepartum haemorrhage

Answer 5

• Spotting- Staining, streaking, or blood spotting noted on underwear or sanitary protection
• Minor haemorrhage- blood loss less than 50ml that has settled
• Major haemorrhage- blood loss of 50-1000ml, with no sign of clinical shock
• Massive haemorrhage- blood loss greater than 1000ml and/or signs of clinical shock

Question 6

Presentation of placental abruption

Answer 6

• Sudden onset severe abdominal pain that is continuous
• Vaginal bleeding (antepartum haemorrhage) and shock (hypotension and tachycardia)
• The degree of bleeding does not necessarily correlate with the degree of abruption since abruptions may be concealed
• Concealed abruption: where the cervical os remains closed and any bleeding that occurs remains in the uterine cavity. This is opposed to revealed abruption
• Foetal distress-> indicated by abnormal CTG or reduced foetal movement
• Characteristic ‘woody’ abdomen on palpation, suggesting a large haemorrhage

Question 7

Investigations for placental abruption

Answer 7

• Abdominal examination (no Bimanual since risk of praevia), consider speculum
• Placental abruption is a clinical diagnosis and there are no sensitive or reliable diagnostic tests available. Ultrasound has limited sensitivity in the identification of retroplacental haemorrhage (fails to detects three-quarters of cases of abruption)
• A with any major haemorrhage: FBC, coag screen, Group and save (4 units crossmatched)
• Foetal monitoring (CTG) should be performed once the mother is stable and resuscitation has commenced (informs decision about delivery)-> may lead to abdominal USS to evaluate heartbeat

Question 8

Management of placental abruption

Answer 8

Initial management of major or massive haemorrhage:
* A-E
* Urgent involvement of a senior obstetrician, midwife and anaethetist
* 2x wide bore cannulas
* FBC, UE, LFT, Coag and Crossmatch for 4 untis
* Fluid and blood resuscitation as required, CTG monitoring of foetus and close monitoring of mother

Further management:
* If there is foetal compromise, should consider caesarean section- Emergency section is required in foetal or maternal (haemodynamically unstable) compromise REGARDLESS OF GESTATION
* If the mother is haemodynamically stable and there is no evidence of foetal distress:
* Induce labour after 37 weeks
* Consider steroids and admit to antenatal ward for close monitoring if < 37 weeks
* Women in labour with active vaginal bleeding require continuous electronic foetal monitoring
* (If fetal death is diagnosed, vaginal birth is the recommended mode of delivery for most women (provided the maternal condition is satisfactory)
* Antenatal steroids can be offered between 24+0 and 34+6 weeks gestation to mature foetal lungs in anticipation of preterm delivery
* Rhesus-D negative women require anti-D prophylaxis when bleeding occurs. A Kleihauer test is used to quantify how much foetal blood is mixed with the maternal blood, to determine the dose of anti-D that is required.
* Mother is at increased risk of PPH- requires active management during the third stage of labour