Chronic Hypertension in Pregnancy

Chronic Hypertension in Pregnancy 

( From NICE Guidance Hypertension in pregnancy: Diagnosis and management 2019) 

Preconception- 

Advice on rest, exercise and weight management- the advice is the same as for healthy pregnant women. Advice on lowering salt in diet.*

Advice for women taking ACE and ARB – There is an increased risk of congenital abnormalities  if these drugs are taken during pregnancy. These drugs should be stopped within  2 days of notification of pregnancy. 

Advice for women taking Thiazide and thiazide like diuretics- there may be an increased risk of  congenital abnormalities and neonatal complications. 

Alternatives drugs should be discussed. If she is taking ACE /ARB For other conditions (renal disease) , discuss alternative treatment. 

Women taking antihypertensives other than ACE, ARB, Thiazide and thiazide like diuretics-  the limited evidence available has not shown an increased risk of congenital malformation with such treatments.

If a woman with chronic hypertension is not on antihypertensive, start her on antihypertensive if sustained SBP is >= 140 OR Sustained DBP > = 90 mm Hg. 

If on antihypertensives, aim for target BP 135/85. 

If her current antihypertensive is safe in pregnancy- Continue the same treatment unless SBP is < 110 mmHg or DBP is < 70 mmHG, or she has symptomatic hypotension. 

  1. Triage PlGF Test (Quidel)- threshold of 100 pg/ml.
  2. Elecsys Immunoassay sFlt-1/PlGF ratio- at  threshold of ≤38.
  • Do not offer planned early delivery before 37 weeks, unless there is any medical complication
  • After 37 weeks- Timing of birth and indication of birth ( Both maternal and fetal) to be agreed between mother and senior Obstetrician. 
  • If planned early birth is necessary, Consider Corticosteroids for fetal lung maturity and Magnesium Sulphate for neuroprotection( As per NICE Guidance on Preterm Birth)
  • CTG to be done only if indicated.

 POSTNATAL CARE– BP Monitoring- Daily for the first 2 days→ at leat once between day 3 and 5 → also as clinically indicated ( e.g when medication is changed) .

Counseling for women on antihypertensive-

Choice of antihypertensive- 

  • avoid using diuretics or angiotensin receptor blockers[5] to treat hypertension in women in the postnatal period who are breastfeeding
  • When possible, try to use medicines which are needed once daily. 
  • OFFER Enalapril to treat hypertension in postpartum women- with monitoring of maternal renal function and maternal serum potassium. 
  • For women of African or Caribbean family origin with hypertension during the postnatal period, consider Nifedipine, Or Amlodipine ( if she has used amlodipine before to control her BP) 
  • If BP is not controlled with single medicine- 
  • 1. Consider a combination of Nifedipine and Enalapril , or Amlodipine and Enalapril → if it doesn’t work→ Consider adding Atenolol or Labetalol  to this combination  OR Swapping one of the medicines being used for Atenolol or labetalol
  • Avoid using diuretics or angiotensin receptor blockers
  • If she is not lactating and not planning to breastfeed– > treat according to NICE guideline on hypertension in adults. 

MONITORING OF THE BABY– ( antihypertensive agents have the potential to transfer into breast milk) 

  • consider monitoring the blood pressure of babies, especially those born preterm, who have symptoms of low blood pressure for the first few weeks
  • – when discharged home, advise women to monitor their babies for drowsiness, lethargy, pallor, cold peripheries or poor feeding

FUTURE HEALTH- 

About 1.7 times increased risk of major cardiovascular event. 

About 1.8 times increased risk of stroke. 

* Salt restriction to prevent ‘gestational hypertension’ or’ pre-eclampsia ‘ is not recommended. 

Contraception ( UKMEC) 

Cu-IUD, LNG IUS, IMP, DMPA, POP, CHC

Adequately controlled Hypertension– all are UKMEC category 1 , except DMPA ( Cat 2 )  and CHC ( Cat 3) 

Consistently elevated BP- Systolic 150 to 159, Diastolic 90 to 99→ All are Cat 1 except CHC ( Cat 3) 

Consistently elevated BP – Systolic >= 160, Diastolic >= 100→ all are cat 1 except DMPA ( cat 2 ) and CHC ( cat 4 ) 

Hypertension with vascular disease – Only Cu IUD is Cat 1 . LNG IUS , POP and IMP are cat 2 , DMPA is Cat 3, CHC is Cat 4 . 

Click the link to read the UKMEC summary table. 

UKMEC SUMMARY TABLE HORMONAL AND INTRAUTERINE CONTRACEPTION

Click here to read the summary on gestational hypertension

Recap- Chronic Hypertension in Pregnancy

  1. Pre- conception- Stop ACE, ARB, Thiazide, Thiazide like diuretics
  2. Threshold to start antihypertensive- 140/90
  3. Target BP – 135/85
  4. Stop treatment if 110/70 or symptomatic hypotension. 
  5. Choice of antihypertensive- Labetalol→ Nifedipine→ methyldopa
  6. Placental Growth Factor Testing to diagnose Pre-Eclampsia
  7. Postnatal- stop methyldopa. Choice of antihypertensive→ Enalapril and /or Nifedipine. BP Daily for 2 days, at least once between day 3 &5 . 
  8. Baby may need monitoring. 
  9. Postnatal follow up- 2 weeks, 6 weeks. 
  10. Contraception- Refer to UKMEC
  11. Implications for future health. 

Read about Gestational Hypertension

Read the Summary on Pre-Eclampsia

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