Antepartum Haemorrhage

Vaginal bleeding occurring after the 24^th week of pregnancy and prior to delivery, usually due to:

• Placenta previa
  Implantation of the placenta round the internal os of the cervix. Classically presents with:
  • Painless, fresh vaginal bleeding
  • Foetal distress is rare
  • Coagulopathy is rare
• Abruptio placentae
  Premature separation of placenta from the decidua basalis. Classically presents with:
  • Painful
  • Generally older bleeding
  • Blood loss may be concealed
  • Significant foetal distress
    Up to 50% foetal mortality.

Epidemiology and Risk Factors

APH:

• Major cause of maternal mortality
• Occurs in 3-5% of pregnancies

Placenta Previa:

• Usually ~1% of total pregnancies
• Risk factors:
  • Prior:
    • Placenta previa
    • LUSCS
    • Myomectomy
    • Endometrial trauma
  • Age
    • < 20 or > 35
  • Smoking
  • Previous uterine trauma
    • Previous surgery
      • Caesarian
      • Curettage
      • Manual removal of placenta
    • Endometritis

Placental abruption:

• Risk factors
  • Maternal thrombophilias
    
  • Placental abruption
    Previous abruption gives ~20% risk of subsequent abruption.
  • Smoking
  • Cocaine
  • Amphetamine

Pathophysiology

Placenta previa classified into:

• Complete (37%)
  Complete coverage of intenal os.
• Partial (27%)
  Partial coverage of the internal os.
• Marginal (37%)
  Placenta encroaches on internal os.

Placental abruption is classified by:

• Degree of blood loss:
  • Mild
  • Moderate
  • Severe
• Placental location:
  • Concealed haemorrhage
    Bleeding trapped in uterus by placenta.
  • External haemorrhage
    Blood flowing out of cervix.
  • External haemorrhage with placental prolapse

Investigations

Maternal investigations are targeted towards assessing extent and consequences of haemorrhage. Investigations will depend on bleeding:

Laboratory:

• Bloods
  • FBE
  • Coag
    If platelet count abnormal (suggestive of coagulopathy).
  • Group and hold
    Cross-match 4 units if major haemorrhage.
  • UEC
  • LFT
  • Kleihauer
    For Rh- mothers, to quantify extent of FMH.

Other:

• CTG
  • Once mother stable or resuscitation commenced
  • Aids decision making on mode of delivery
  • In general, a non-reassuring trace should result in expedited delivery.

Management

Key determination is whether emergency caesarian is indicated, which is contingent on whether there is:

• Active bleeding
  
• A viable pregnancy

Resuscitation:

Specific Therapy:

• Procedural
  • Delivery
    Ultimately required for both praevia and abruption.
    • Emergency caesarian
      • Often under GA
      • Massive transfusion often required
        
        • Transfuse at 1:1:1, as per trauma resuscitation
        • Early coagulation profile and haematology involvement
      • Careful induction of anaesthesia required
      • Significant likelihood of post-partum hysterectomy

Marginal and Ineffective Therapies

Anaesthetic Considerations

• C
  • High likelihood of massive transfusion
  • Invasive arterial monitoring
• D
  • Anaesthetic technique
    • Regional
      Appropriate if no evidence of hypovolaemia.
      • Reduced blood loss
      • Reduced aspiration
      • ↑ hypotension
      • Technical difficulty
    • General
      • Haemodynamic stability
      • Difficult airway and aspiration risk
• H
  • DIC
    May develop following profound haemorrhage.

Complications

Maternal complications:

• Haemorrhage
  • Death
  • Shock
  • Anaemia
  • Coagulopathy
  • Prolonged hospital stay
  • Blood transfusion

Foetal complications:

• Haemorrhage
  Particularly in vasa praevia or abruption.
• Hypoxia
  • Death
• Prematurity
• IUGR

Prognosis

---

References

1. RCOG. Antepartum Haemorrhage: Green-top Guideline. RCOG. 2011.
2. Bersten, A. D., & Handy, J. M. (2018). Oh’s Intensive Care Manual. Elsevier Gezondheidszorg.