Hypertension (high BP) in pregnancy

Systolic BP 140mmHg or more and/or diastolic BP 90mmHg or more

  • Confirm by repeated readings over several hours
  • Re-check with manual sphygmomanometer if available

Types of hypertension (high BP) in pregnancy

  • Chronic hypertension
    • Known to have high BP before pregnancy
    • OR high BP recorded in first 20 weeks of pregnancy
  • Pregnancy-induced hypertension
    • High BP first recorded when more than 20 weeks pregnant
  • Preeclampsia
    • More than 20 weeks pregnant
    • High BP AND one OR more other signs or symptoms — Table 2.15
    • If systolic BP 170mmHg or more OR diastolic BP 110mmHg or more — medical emergency — urgent medical consult

Hypertension can cause

  • Poor growth of baby
  • Death of unborn baby 
  • Placental abruption (part or all of placenta comes away from wall of uterus)
  • Preterm labour or preterm birth
  • Worsening of chronic high BP — 'end-organ' damage for mother, eg to kidneys, liver, brain
  • Eclampsia (seizures when severe high BP)

Check

  • Assess risk factors for preeclampsia at first antenatal visit — Table 2.14
    • If risk factors — medical consult
    • May need to see obstetrician early in pregnancy
    • May suggest low dose aspirin or calcium supplements to reduce risk
  • If risk factors — urinalysis for protein each visit

Table 2.14   Risk factors for preeclampsia

Do — if BP high at antenatal visit

  • Take BP again after woman has rested for 10 minutes
  • Finish routine antenatal check — note if protein on U/A
  • Check file notes for
    • Risk factors for preeclampsia
    • Gestation (how many weeks pregnant)
    • U/A or albumin creatinine ratio (ACR) results earlier in pregnancy — any protein
    • Last urine MC&S
  • Ask about symptoms of preeclampsia —  Table 2.15
  • Check for signs of preeclampsia —  Table 2.15
  • Medical consult about findings and management
    • If managing as preeclampsia — see Preeclampsia straight away
    • If managing as high BP — see Pregnancy-induced high BP or Chronic high BP

Table 2.15   Signs and symptoms of pre-eclampsia and eclampsia

Pregnancy-induced hypertension

Need to send to hospital to check for preeclampsia and work out management plan

Check

  • If signs or symptoms of preeclampsia — urine for U/A and MC&S

Do

  • Bloods for FBC, UEC, LFT
  • Medical consult about sending to hospital — straight away or non-urgent referral
  • If sending to hospital straight away
    • Medical consult about whether to start anti-hypertensive medicine to reduce BP
    • Check BP every hour until transfer
    • Urgent medical consult if systolic more than 160mmHg or diastolic 100mmHg
  • If non-urgent referral
    • See every day while waiting for hospital appointment
    • Do routine antenatal check
    • Ask about symptoms of preeclampsia — Table 2.15
    • Medical consult every day about findings

If ongoing management in community

After review in hospital — may be managed in community. Management plan should include

  • More frequent antenatal checks
    • Ask about symptoms of preeclampsia at each visit — Table 2.15
    • Medical consult about findings from each visit
  • Regular hospital checks, including obstetric ultrasounds and cardiotocogram (CTG)
  • Plan for birth in hospital — may need epidural or caesarean section

BP control

  • BP target — usually less than 140/90mmHg
    • Plan to send to hospital if preeclampsia or severe high BP develop
  • Do not use ACE inhibitor or ARB to control BP — contraindicated in pregnancy
  • Often use methyldopa or labetalol
    • Always use if systolic BP 160mmHg or more or diastolic BP 100mmHg or more
    • May be used if systolic BP 140–160mmHg or diastolic BP 90–100mmHg

 Investigations

  • Take blood for FBC, UEC, LFT once a week, or twice a week if preeclampsia
  • Take blood on day transport is available — so it gets to lab in time for platelet count
  • If low platelet count or falling Hb — take blood for clotting studies, blood film, LDH, fibrinogen
  • Collect urine for ACR (albumin creatinine ratio rather than 24 hour collection) once or twice a week

Follow-up

Chronic hypertension

If planning pregnancy — see Preconception care

Check

First antenatal visit

  • Check file notes — history of kidney disease, BP management plan
  • Also take blood for UEC, LFT, uric acid
  • Urine albumin creatinine ratio (ACR)

After 20 weeks

  • For signs or symptoms of preeclampsia — Table 2.15

Do

First antenatal visit

  • Medical consult — medicines review
    • Review beta blockers and diuretics
    • Stop ACE inhibitor or ARB — both contraindicated in pregnancy
    • Use a safer BP lowering medicine — methyldopa oral — 125mg twice a day (bd) increasing as required up to 500mg 3 times a day (tds)
      OR clonidine oral — 50microgram twice a day (bd) increasing as required up to 300microgram twice a day (bd)
      AND aspirin oral — 75–150mg at night 
      AND calcium supplement oral — 1.5g daily
    • Arrange renal ultrasound (if not already done) to look for causes of high BP. Do at same time as obstetric ultrasound
    • Arrange medical follow up, refer to specialist and obstetrician as required

Follow management plan

  • Routine antenatal care
  • Additional monitoring and treatment as advised by specialist
  • BP target
  • Plan for birth in hospital — may need epidural or caesarean section

Follow-up

Unplanned birth in community

If woman with high BP goes into labour in community

Do not

Do not give nifedipine to stop labour unless instructed by obstetrician — may be asked to give nifedipine to control BP

Do not use ergometrine alone or in combination. Only use plain oxytocin

Do

  • Urgent medical consult about 
    • Sending to hospital
    • Stopping labour with nifedipine
    • Management plan if birthing in community
  • If labour proceeds 
    • See Labour and birth
    • Give good pain relief as directed by doctor or midwife
    • Get ready for a sick baby — see Newborn resuscitation
    • Be ready in case woman has a fit
    • Send mother and baby to hospital after birth — still at risk of complications