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.
- Triage PlGF Test (Quidel)- threshold of 100 pg/ml.
- 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
- Pre- conception- Stop ACE, ARB, Thiazide, Thiazide like diuretics
- Threshold to start antihypertensive- 140/90
- Target BP – 135/85
- Stop treatment if 110/70 or symptomatic hypotension.
- Choice of antihypertensive- Labetalol→ Nifedipine→ methyldopa
- Placental Growth Factor Testing to diagnose Pre-Eclampsia
- Postnatal- stop methyldopa. Choice of antihypertensive→ Enalapril and /or Nifedipine. BP Daily for 2 days, at least once between day 3 &5 .
- Baby may need monitoring.
- Postnatal follow up- 2 weeks, 6 weeks.
- Contraception- Refer to UKMEC
- Implications for future health.