e-learning | Hypertension in pregnancy

This is an updated guideline from NICE on managing hypertension in pregnancy. It was first published in 2010 and has been updated in June 19.

I will do a summary of the bits of the guideline that are relevant to us, but the following are some of the key changes:

  • Choice of medications. This has been tightened up. Now they advise labetolol first line, nifedipine second line and methyldopa third line.
  • Target BP level. This has been lowered. For both chronic and gestational hypertension, the target BP is now 135/85.
  • Risk of recurrence. There is a 1 in 5 chance of recurrence in future pregnancies.
  • Future risks. There is a small increased risk of cardiovascular disease in later life in people who have had hypertensive problems in pregnancy.
  • Aspirin should be used from 12/40 until birth at a dose of 75 - 150mg (there is no clear evidence about the best dose). This is unlicensed. This isn't new advice, but I thought it worth highlighting as often we may need to initiate it. Women need it who have chronic hypertension or have risk factors for pre-eclampsia as advised below.
  • Patients who had pre-eclampsia should have their urine dipped at 6-8/52. If they still have 1+ or more of protein, they need a further review at three months.

Definitions

Chronic hypertension. This is pre-existing hypertension that was present at the time of booking, or where it presents before 20/40.

Gestational hypertension. This is new hypertension without proteinuria that presents after 20/40.

Pre-eclampsia. This is new hypertension of over 140/90 that presents after 20/40 with at least 1 of:

  • Significant proteinuria (PCR > 30 mg/mmol , ACR > 8 mg/mmol or 2+ on dipstix).
  • Maternal organ insufficiency (e.g. renal dysfunction, liver involvement, neurological complications or haematological complications).
  • Uteroplacental dysfunction (e.g. IUGR, stillbirth or abnormal dopplers).

How should we test for proteinuria?

If dipstix 1+ or more, then do protein-creatinine ratio PCR or albumin-creatinine ratio ACR. Don't use a first void of the morning.

  • PCR. Use a cut off of 30 mg/mmol or over to determine significant proteinuria.
  • ACR. Use a cut off of 8 mg/mmol or over to determine significant proteinuria.

Obviously interpret the results in the clinical context. If pre-eclampsia is still suspected, then repeat the test and review the patient.

How should we manage women at risk of pre-eclampsia?

Advise women of the symptoms of pre-eclampsia.

Antiplatelet treatment

Some women at risk will need to take aspirin at 75 - 150mg a day from 12/40 until birth. This is unlicensed and informed consent must be sought.

High risk patients should take aspirin if they have one of the following risk factors:

  • Hypertension in a previous pregnancy.
  • CKD.
  • Autoimmune disease (e.g. SLE or antiphospholipid syndrome).
  • Diabetes (type 1 or 2).
  • Chronic hypertension.

Moderate risk patients should take aspirin if they have two or more of the following risk factors:

  • First pregnancy.
  • Age over 40.
  • Pregnancy interval > 10 yrs.
  • BMI > 35 at first visit.
  • Family history of pre-eclampsia.
  • Multiple pregnancy.

How should we manage women with chronic (pre-existing) hypertension?

Pre-pregnancy advice. Offer referral to a specialist clinic if planning a pregnancy.

What medications should we use in women planning a pregnancy?

  • ACEi/ARB (angiotension receptor blockers). There is an increased risk of congenital malformations. Consider alternatives if women are planning a pregnancy. If they become pregnant, they should be stopped within 2d and an alternative started.
  • Chlorothiazides. There may be an increased risk of congenital malformations and neonatal complications. Consider alternative if planning a pregnancy.
  • Other medications. No evidence of harm during pregnancy. You would obviously want to double check this in the BNF for the patient in front of you.

What medications should be used to treat chronic hypertension in pregnancy?

  • First line - labetolol.
  • Second line - nifedipine.
  • Third line - methyldopa.

Medication should be started if there is a sustained rise in BP to 140/90 or more.

Target BP is 135/85 (this is lower than previous targets as new evidence suggests better outcomes with lower target BPs).

Continue medications unless there is a sustained drop in BP to less than 110/70 or there is symptomatic hypotension.

How often should patients be monitored?

Anywhere between 1 - 4 weeks, depending on the severity.

Should antiplatelets be used?

Offer aspirin at 75 - 150mg OD from 12/40 to birth. This is unlicensed.

PIGF (Placental growth factor) testing.

Offer PIGF testing once from 20 - 35/40 to rule out pre-eclampsia if it is suspected.

How do we manage women post-natally?

  • Target BP - 140/90.
  • Monitor on day one and day two then at least 3-5d after birth, then as indicated.
  • Methyldopa? If using this antenatally, then stop it within 2d and start an alternative.
  • If breast-feeding, ensure the safety of any medications used (see below). The baby should be checked daily for 2d.
  • Review at 2/52 and 6/52 with the GP or specialist.

How should we manage patients with gestational hypertension?

Firstly, patients should be fully assessed in secondary care, so hopefully we will have a good care plan to work from if we need to get involved in management here.

How do we manage ladies with moderate gestational hypertension (BP 140/90 - 159/109)?

  • Treat patients if they have a sustained BP over 140/90.
  • Aim for a target BP of 135/85. Measure BP once or twice a week until this target is reached.
  • Dipstix urine once or twice a week.
  • Measure FBC, LFT and UE at presentation then weekly.
  • Carry out PIGF testing on one occasion between 20 and 35/40 if pre-eclampsia is suspected. Use the NICE guideline on PIGF testing when deciding when to measure it. You can read my blog post on PIGF testing for a quick reminder.
  • The fetal heart should be auscultated at each visit. USS should be done at presentation and then every 2-4/52 thereafter if clinically indicated.

Birth shouldn't be planned before  37/40 unless there are other indications to do so.

How should patients with severe gestational hypertension (BP 160/110 or more) be managed?

Women should be admitted until their BP falls back to the moderate level. Otherwise management is the same as it would be for women with moderate gestational hypertension. The only difference is that USS should be done every 2/52 as long as severe hypertension persists.

What medications should be used in gestational hypertension?

The same as for chronic hypertension (labetolol first line, then nifedipine, then methyldopa).

How do we manage women with gestational hypertension post-delivery?

  • If no treatment has been needed so far, only start treatment if the BP is 150/100 or more.
  • Measure the BP daily for 2d, then once between 3-5d then as indicated.
  • If methyldopa has been used, it should be stopped within 2d of delivery.
  • If BP < 130/80, then reduce the medication.
  • Patients should be reviewed 2/52 after delivery then at the 6/52 check.
  • Advise women that the duration of post-natal treatment is likely to be equal to that of the duration of their antenatal treatment.

How should patients with pre-eclampsia be managed?

Patients will be managed in secondary care, so I'm not going to go into too much detail here. I'll just cover the bits that are most relevant to us.

Among other fairly obvious warning signs, there are certain blood markers that would give rise to concern in a patient with pre-eclampsia. These include new and persistent changes in:

  • Creatinine - rise of 90 micromol/L or 1mg/100ml or more.
  • ALT - a rise to over 70 IU/L, or twice the upper limit of normal.
  • Platelets - a fall in platelets to under 150,000/microlitre.

How should patients with pre-eclampsia be managed postnatally?

If methyldopa has been used, it should be stopped within 2d.

Patients can be transferred to the community if their BP is less than 150/100, there are no symptoms of pre-eclampsia and their bloods are either stable or improving.

If they didn't take medication during pregnancy, then their BP should be checked at 3-5d postnatally, then every 2d for 2/52. They should be asked about headaches and epigastric pain at every visit. Medication should be started if their BP is > 150/100.

If they did take medication during pregnancy, then their BP should be measured every 1-2d until they are off medications and their BP is normal.

Consider reducing medications once their BP is < 140/90. Do reduce their medications if their BP is < 130/80.

Bloods should be done at 48-72 hrs post delivery or step down from critical care. Once they are normal, don't remeasure them. Repeat them at 'clinically indicated' intervals.

Proteinuria. Dipstix at 6-8/52. If they still have 1+ protein or more, then offer further review with a GP or specialist at 3m to recheck renal function. At that point, consider referring as you would any other patient with chronic kidney disease.

What advice should we give women regarding medications and breast-feeding?

Explain that the drugs used can pass into milk, but that they are only present in small amounts and they are unlikely to have any effect on the baby.

Consider monitoring the baby's BP for the first few weeks, especially if they were born premature. Watch out for signs of hypotension in the baby (drowsiness, lethargy, pallor, cold peripheries or poor feeding).

What drugs should be used?

Offer enalapril first line. If the patient is of Black African or Caribbean descent, then consider either nifedipine or amlodipine first line. Generally amlodipine would be used if it has been used successfully in the past.

If 2 medications are needed then:

  • Enalapril +
  • Nifedipine or amlodipine

If this combination is not tolerated then:

  •  Add atenolol or labetolol or
  • Swap one of the medications already used for one of the above.

Where possible avoid angiotensin receptor blockers and diuretics whilst breast-feeding.

What advice should be given to patients who have had hypertension in pregnancy?

  • The pre-eclampsia recurrence risk rises if the pregnancy interval is over 10 yrs.
  • If there has been pre-eclampsia, then keeping your BMI between 18.5 and 24.9 lowers the risk of recurrence.
  • Renal risks. If the patient had pre-eclampsia and at 6/52 follow up they have normal BP and no proteinuria, then they have a raised relative risk of end stage renal failure. However, the absolute risk is low, so the patient needs no specific follow-up.
  • If the patient delivered before 34/40, then consider pre-pregnancy counselling to discuss their risk factors and how to lower them.

1 Response

  1. thank you. very useful

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