Pre-existing Hypertension in pregnancy

Question 1

Definition

Answer 1

When BP is already treated or exceeds systolic 140 and or diastolic 90 before 20w

Question 2

How many pregnancies are affected by underlying hypertension?

Answer 2

5%

Question 3

Risk factors?

Answer 3

Older women
Obese
Positive FHx
Developed HNT while taking COCP

Question 4

Patients with pregnancy induced HNT have a greater predisposition to…

Answer 4

…HNT and may require treatment in later life

Question 5

Most common form?

Answer 5

Primary HNT

Question 6

What causes secondary HNT?

Answer 6

Obesity
Diabetes
Renal disease (e.g. PCKD, RAS, chronic pyelonephritis)
Rare causes (phaeochromocytoma, Cushing’s syndrome, cardiac disease, coarctation of aorta)

Question 7

Clinical features

Answer 7

HNT increases in late pregnancy (after dip in second trimester)
Fundal changes
Renal bruit
Radiofemoral delay

Question 8

Complications

Answer 8

Greater risk of pre-eclampsia (sixfold) and HNT
FGR
Abruption
Also rule out rare causes (see secondary cause, rare list)

Question 9

Ix

Answer 9

BP monitoring
look for underlying cause (e.g. kidney function in suspected renal impairment, VMA collections for phaeochromocytoma)
Proteinuria in suspected pre-eclampsia

Question 10

Management pre-conception

Answer 10

ACEi are teratogenic and affect foetal urine production; ARBs and thiazides can cause congenital abnormalities in foetus.
Switch mother to labetalol or methyldopa preconception, nifedipine as a second line agent.

Question 11

Management antenatally

Answer 11

Use appropriate HNT medication.
If secondary cause, treat underlying problem.
Aim for BP <150/90 (140/90 if end organ damage) but keep diastolic >80.
Give aspirin 75mg PO OD from conception to term.
Admit if BP >160/110.
USS every 4w from 28w to assess foetal growth, amniotic fluid volume, UAD.
Aim for induction of labour around EDD.

Question 12

Management intrapartum

Answer 12

During labour, monitor BP hourly if <159/109, continually if >160/110
If severe HNT unresponsive to treatment, advise operative delivery.
Give oxytocin alone in third stage of labour (ergometrine causes severe HNT, risk of haemorrhagic stroke)

Question 13

Management postnatal

Answer 13

Check on days 1,2 and once on days 3-5 and at 2w.
Change methyldopa to alternative antiHNT (as inc risk of postnatal depression).
Avoid diuretics if breastfeeding (labetalol, atenolol, metoprolol, captopril and enalapril are safe).