2.1 Hypertensive Disorders

Question 1

Chronic hypertension & pathophysiology

Answer 1

• Essential/pre-existing hypertension
• Hypertension secondary to other medical conditions
• BP > 140 / 90 before 20 weeks
• Not yet related to placenta

Pathophys:

Question 2

Gestational hypertension & pathophysiology

Answer 2

• Diastolic >90 mmHg or systolic >140 mmHg repeated over 4 hours
• New onset hypertension
• After 20 weeks gestation
• No maternal or foetal features of preeclampsia
• Followed by a return to normal BP within 3 months postpartum

Pathophysiology:
- Impairment in the physiological process of trophoblastic invasion of the maternal spiral arteries and their remodelling from tortuous narrow muscular vessels into large non-muscular channels
- Increased formation of vasoconstrictors → Vasospasm and increased systemic resistance

Question 3

Preeclampsia & pathophysiology

Answer 3

• Hypertension after 20 weeks gestation up to 6 weeks postpartum
• Involvement of one or more organ systems and/or the foetus
• Renal, haematological, liver, neuro, pulmonary oedema, foetal growth restriction
• Proteinuria common (marker of kidney damage)
• Seizures = eclampsia
• Mild/Moderate: 140 / 90+ at least twice over several hours, proteinuria >300 mg in 24 hr collection or protein to creatinine >30 mg/mmol
• Severe PE: >170 / 110

Pathophysiology:
- Abnormal placenta → spinal arteries become fibrous & narrow → Poor placental perfusion → high-impedance circulation instead of the low pressure system for baby oxygenation
- Poorly perfused placenta → releases proinflammatory proteins → endothelial cell damage → vasoconstriction & kidneys retain more salt → hypertension

Question 4

Chronic hypertension - maternal & fetal complications

Answer 4

Maternal:
- Increased risk for PE, preterm birth, gestational HTN, uteroplacental insufficiency

Fetal:
- FGR, premature birth, placental abruption, stillbirth

Question 5

Gestational hypertension - maternal & fetal complications

Answer 5

Maternal:
- Development of proteinuria

Fetal:
- IUGR, preterm birth, placental abruption, stillbirth

Question 6

Preeclampsia - maternal & fetal complications

Answer 6

Maternal:
- Abnormal coagulation system, disturbed liver function, renal failure, cerebral ischaemia

Fetal:
- FGR, fetal death, placental abruption

Question 7

Maternal signs of preeclampsia

Answer 7

• 140 / 90 or 160 / 110 BP for severe PE
• Local vasospasm → reduced blood flow to kidneys → glomerular damage = proteinuria
• Local vasospasm → reduces blood flow to retina = scotoma, blurred vision, flashing lights
• Local vasospasm → reduced blood flow to the liver → injury and swelling → increased liver enzymes → stretches liver capsule = R) upper quadrant pain or epigastric pain
• Endothelial injury → HELLP - Hemolysis (platelets caught in thrombi/clots - death of blood cells causing anaemia), Elevated Liver enzymes, Low Platelets
• Endothelial injury → vascular permeability → liquid move to tissues = generalised oedema (legs, face, hands), pulmonary oedema (cough, SOB), cerebral oedema (headaches, confusion, seizures)

Question 8

HTN midwifery care

Answer 8

Maternal assessments:
- History: headaches, visual disturbances, epigastric or right upper quadrant pain
- Vital signs: BP, pulse, RR, temp
- General examination: abdo palp, reflexes, clonus

Investigations:
- Spot urine protein:creatinine ratio
- Midstream urine, FBE, UEC, LFT, uric acid

Fetal assessments:
- CTG if >28 weeks
- US for biometry, AFI, doppler studies, biophysical profile
- SFH, EFW

Question 9

Severe PE Stabilisation management

Answer 9

1. Control BP - admission to hospital, antihypertensive therapy (nifedipine, methyldopa, hydralazine)
2. Prevent eclampsia - mag sulph, decrease BP, reflex test, potential epidural
3. Care of fetus - continuous CTG

Question 10

Timing of birth considerations

Answer 10

• Only “cure” for clinically diagnosed PE
• Foetus is mature or maternal condition deteriorates or evidence of significant foetal compromise
• 24 - 34 weeks urgent delivery required → corticosteroids administered to mother to stimulate foetal lung maturation and surfactant production
• Foetal indications for immediate delivery - IUGR, non-reassuring CTG, oligohydramnios
• Maternal indications for immediate delivery - progressive liver or renal function deterioration, suspected placental abruption, persistent severe headache/visual changes, severe persistent epigastric pain, nausea, vomiting

Question 11

Follow up care

Answer 11

• 72 hrs pp - monitor BP and continue therapy
• Strict FBC - can ease off PN after diuresis has occurred (approx. 24 hours)
• Pain management - analgesia
• Antihypertensive medications
• Postnatal debriefing and follow-up consultation - also for partner
• Foetal umbi lactates, skin-to-skin, expressing
• Syntocinon 10 mg in 3rd stage (to manage BP and deal with PPH later)