IC16 Hypertensive disorders in Pregnancy

Question 1

Differentiate the hypertensive disorders in pregnancy

Answer 1

New onset after 20 weeks of gestation
1) Gestational HTN
2) Preeclampsia – Proteinuria, signs of end-organ dysfunction, uteroplacental dysfunction

Pre-existing before the 20 weeks of gestation
1) Chronic HTN
2) Chronic HTN with superimposed preeclampsia – New onset proteinuria only after 20 weeks of gestation

Question 2

What do we use to measure proteinuria and signs of end organ damage?

Answer 2

Proteinuria – 24 h urinary protein, dipstick protein, uPCR (Urine protein : Creatinine ratio)

End organ damage – Platelet count, LFT 2X ULN, SCr doubled, pulmonary edema, neurological complications

Question 3

What is the consequence of preeclampsia?

Answer 3

Eclampsia (New onset seizures)

Question 4

How to prevent preeclampsia and in whom? When should it be started and for how long?

Purpose of prevention?

Answer 4

Low dose aspirin 100mg daily for high risk patients (HTN on previous pregnancy, multifetal gestation, autoimmune disease, DM, CKD)

After week 12 ideally before week 16 until delivery

Hypothesis: Improves the utero-placental blood flow by inhibiting thromboxane A2, a contributing factor to preeclampsia

Question 5

Which 2 medications are commonly used in practice for HTN in pregnancy?

Answer 5

Labetalol and Nifedipine ER

Question 6

Why is labetalol preferred over Beta blockers for HTN in pregnancy?

Answer 6

Less ADR on uteroplacental blood flow and fetal growth

Question 7

Which anti-HTN medication has extensive safety data in pregnancy? Why is it not usually used?

Answer 7

Methyldopa; low potency, more ADR (sedation, dizziness) that is unideal in pregnancy

Question 8

Which is a 2nd or 3rd line HTN drug in pregnancy?

Answer 8

Hydrochlorothiazide - Due to concerns for potential interference with normal blood volume expansion during pregnancy

Question 9

What to monitor for when using labetalol or nifedipine ER?

Answer 9

Monitor for bronchoconstrictive effects, bradycardia.

Monitor for pedal edema, flushing, headaches.

Question 10

Why do we tend not to use hydralazine for HTN in pregnancy?

Answer 10

ADRs mimics symptoms associated with severe preeclampsia and imminent eclampsia (E.g. N/V, palpitation, flushing, headache, tremor)

Question 11

What is the BP threshold to initiate treatment?

Answer 11

Traditionally - Severe chronic HTN > 160/110 mmHg due to fetal safety concerns

Recent evidence - 140/90 mmHg