2.2 Cardiac Disease & Rhesus Isoimmunisation

Question 1

Normal cardiovascular changes in pregnancy

Answer 1

• Mild dyspnea especially upon exercise
• Fatigue
• Oedema
• Occasional palpitations and dysrhythmia
• Increased risk for thromboembolism
• 3rd heart sound
• Soft systolic murmur - due to increased flow through the valves
• Reflux

Question 2

Abnormal cardiovascular changes in pregnancy

Answer 2

• Any diastolic or continuous murmur
• Any systolic murmur with a thrill
• Clubbing, cyanosis, jugular vein distention, dyspnea, orthopnea, palpitations
• 4th heart sound - signs of diastolic failure
• Unequivocal heart enlargement
• Pulmonary hypertension
• Nocturnal cough
• Oedema beyond the ankles (upper limbs)

Question 3

Midwifery care for women with cardiac disease

Answer 3

Medical management:
- ECGs, medication management, growth scans (heart and dopplers), foetal echo, anticoagulants

Labour:
- Shortened second stage is preferable (syntocinon and assisted deliveries), vaginal delivery preferred (due to lower blood loss, decreased risk of blood clots), continuous CTG, obs, 5-lead ECG (if indicated by cardiologist), FBC, just synt going slower - no CSL.

Third stage:
- active management (syntocinon - avoid syntometrine & ergometrine as this increases cardiac factors)

Postnatal:
- close monitoring in first 72 hours (haemodynamic shift), HDU or 1:1 in BS for 24 hours, stable 1:1 on ward, weary of blood clots (TEDs, clexane, recommencing anticoagulants), early mobilisation, analgesia for pain management

Cardiologist - women with cardiac conditions should consult with a cardiologist for a preconception evaluation and close follow-ups throughout pregnancy
Obstetrician, paediatrician (intrapartum/postnatal period), neonatologist (once baby is born, especially for congenital diseases)

Anaesthetist - recommend potentially early epidural

Education - explain the increased risk of pregnancy

Question 4

Rh isoimmunisation - pathophysiology

Answer 4

Rh- mother (no Rhesus surface antigen on red blood cells) carries Rh+ foetus (Rhesus surface antigen on red blood cells) and develops antibodies which attack foetal RBC

Sensitising event → spill of foetal blood into maternal circulation → maternal blood recognises foetal Rh+ blood cells as foreign → production of Rh antibodies in response (wont affect first preg but will for second as antibodies still producing) → attacks foetal red blood cells → haemolysis

Future pregnancy implication - sensitisation causes memory cells which will rapidly respond in Rh+ blood cells in future pregnancies

Question 5

Sensitising events of Rhesus Isoimmunisation

Answer 5

Trimester 1:
- Spontaneous abortion
- Pregnancy termination
- Ectopic pregnancy
- Chorionic villi sampling

Trimester 2:
- Amniocentesis
- Antepartum haemorrhage - placental
- Abdominal trauma - placental abruption

Trimester 3:
- External cephalic version
- Antepartum haemorrhage
- Abdominal trauma
- Birth of placenta

Question 6

Care pathway - Prophylactic use of Rh D immunoglobin in pregnancy

Answer 6

• Woman’s blood group and antibody screen in pregnancy confirms Rh D negative → at 11 weeks determine foetal RHD status via NIPT of maternal blood sample → foetus predicted RhD positive or uncertain → at 28 weeks retest antibody screen and administer first dose of Rh D IG 625 IU → at 34 weeks administer 2nd dose Rh D Ig

After birth:
- Cord blood or neonatal testing to determine foetal Rh D type → RhD positive foetus → immediately administer Rh D ig 625 IU (best within 72 hours but can be up to 10 days)
- Kleihaur Test - measures foetal blood spill in maternal circulation → More significant (6mls/625 IU) = more anti D doses to destroy foetal blood cells
- Indirect Coombes - determines any previous sensitisation to the Rh D antigen - important for second pregnancy w/ Rh+ child - memory cells recognise baby’s blood cells as foreign bodies and attacks foetus
- Anaemia, miscarriage, jaundice