What is the management approach for a pregnant woman with chronic hypertension (CHTN) and fetal growth restriction (FGR)?

Management of Chronic Hypertension with Fetal Growth Restriction in Pregnancy

Pregnant women with chronic hypertension (CHTN) and fetal growth restriction (FGR) require intensive monitoring and targeted management with antihypertensive therapy to maintain blood pressure between 110-140/80-85 mmHg, along with serial fetal assessment and timely delivery based on the severity of FGR and Doppler findings. 1

Blood Pressure Management

• Control blood pressure to the range of 110-140/80-85 mmHg using appropriate antihypertensives 1
• First-line antihypertensive options include:
  • Labetalol
  • Methyldopa
  • Nifedipine
  • Oxprenolol
• Second or third-line agents include prazosin and hydralazine 1
• Home BP monitoring is recommended as a useful adjunct to clinic visits (verify device accuracy against a sphygmomanometer) 1

The CHIPS trial demonstrated that targeting a diastolic BP of 85 mmHg reduced the likelihood of developing accelerated maternal hypertension without adverse fetal outcomes compared to targeting higher BP levels 1

Fetal Assessment Protocol

Initial Assessment

• Perform fetal biometry, amniotic fluid volume assessment, and umbilical artery (UA) Doppler waveform analysis at diagnosis 1
• Diagnosis of FGR is confirmed when estimated fetal weight is <10th centile (particularly concerning when <3rd centile) 1

Ongoing Monitoring

1. For confirmed FGR:

   • Fetal growth assessment every 2 weeks
   • Regular amniotic fluid volume and UA Doppler assessment 1

2. If UA Doppler shows increased resistance (pulsatility index >95th centile):

   • Increase surveillance to weekly intervals or more frequently as needed 1

3. If absent end-diastolic flow in UA before 34 weeks:

   • Daily cardiotocograph monitoring
   • Twice weekly UA Doppler
   • Regular amniotic fluid volume assessment
   • Daily discussion with consultant obstetrician 1

4. If reversed end-diastolic flow in UA before 30 weeks:

   • Hospital admission
   • Daily cardiotocograph monitoring
   • Three times weekly UA Doppler
   • Regular amniotic fluid volume assessment
   • Consider fetal medicine specialist consultation 1

Timing of Delivery

• For absent end-diastolic flow: Consider delivery no later than 34 weeks gestation

  • Earlier delivery may be indicated with poor interval growth or deteriorating sonographic variables 1

• For reversed end-diastolic flow: Consider delivery no later than 30 weeks gestation

  • Earlier delivery may be indicated with deteriorating sonographic variables 1

• For stable FGR without severe Doppler abnormalities: Individualized timing based on maternal condition and fetal assessment 1

Additional Management Considerations

• Corticosteroids: Administer between 24+0 and 34+0 weeks for fetal lung maturation (may be given up to 38+0 weeks for planned cesarean delivery) 1

• Magnesium sulfate: Administer for fetal neuroprotection if delivery is planned before 32 weeks gestation 1

• Mode of delivery: Likely cesarean section when absent or reversed end-diastolic flow UA Doppler waveforms are present, or in very preterm gestations 1

• Placental examination: Histopathologic examination is strongly recommended in all FGR cases to understand underlying causes and guide management in subsequent pregnancies 1

Monitoring for Superimposed Preeclampsia

• Regular urinalysis at each visit
• Clinical assessment and blood tests (Hb, platelet count, liver enzymes, uric acid, creatinine) at minimum at 28 and 34 weeks 1
• More frequent monitoring if concerning symptoms or signs develop

Common Pitfalls to Avoid

1. Inadequate BP control: Failure to maintain BP in target range can worsen placental perfusion and exacerbate FGR

2. Insufficient fetal monitoring: Missing deteriorating Doppler patterns that indicate need for delivery

3. Delayed delivery: Waiting too long to deliver in cases of severe FGR with abnormal Doppler findings

4. Failure to recognize superimposed preeclampsia: This complication requires more aggressive management and often earlier delivery

5. Inadequate documentation: Cord arterial and venous pH should be recorded for all FGR infants to guide postnatal management 1

By following this structured approach to management, clinicians can optimize outcomes for both mother and fetus in pregnancies complicated by chronic hypertension and fetal growth restriction.