What are the recent developments and studies related to Pregnancy-Induced Hypertension (PIH) management and prevention in pregnancy?

Recent Developments in Pregnancy-Induced Hypertension (PIH) Management

Low-dose aspirin (100-150 mg/day) starting at 12-16 weeks of gestation is now recommended for prevention of preeclampsia in high-risk pregnant individuals, including those with type 1 or type 2 diabetes. 1

Prevention Strategies

• Low-dose aspirin prophylaxis has emerged as a key preventive measure for preeclampsia, with recent evidence showing that doses <100 mg are not effective, requiring doses of 100-150 mg daily (in the US, 162 mg may be acceptable using two 81-mg tablets) 1
• Aspirin should be initiated between 12-16 weeks of gestation (optimally before 16 weeks) and continued until delivery for maximum effectiveness 1
• For individuals with a history of hypertensive disorders of pregnancy (HDP), low-dose aspirin should be administered in subsequent pregnancies to reduce recurrence risk 1
• High-risk individuals who should receive aspirin prophylaxis include those with:
  • History of preeclampsia, especially early-onset (<28 weeks)
  • Type 1 or type 2 diabetes
  • Chronic hypertension
  • Renal disease
  • Autoimmune disease
  • Multifetal gestation 2, 3

Blood Pressure Management Guidelines

• Recent evidence supports a blood pressure goal of 110-135/85 mmHg during pregnancy to reduce the risk of unmanaged maternal hypertension while minimizing impaired fetal growth 1
• For pregnant individuals with diabetes and chronic hypertension, a blood pressure threshold of 140/90 mmHg for initiation or titration of therapy is associated with better pregnancy outcomes 1
• Therapy should be deintensified for blood pressure <90/60 mmHg to avoid hypoperfusion 1
• There has been a shift in recognizing the detrimental effects of permissive hypertension in pregnancy, with lower BP targets generally associated with improved outcomes 1

Medication Safety in Pregnancy

• Medications known to be effective and safe for hypertension in pregnancy include:
  • Methyldopa (preferred based on long-term safety data)
  • Labetalol (increasingly preferred over methyldopa due to reduced side effects)
  • Nifedipine
  • Clonidine 1
• ACE inhibitors, angiotensin receptor blockers (ARBs), and direct renin inhibitors are strictly contraindicated during pregnancy due to severe fetotoxicity, particularly in the second and third trimesters 1
• Beta-blockers are generally safe, though atenolol is not recommended due to reports of intrauterine growth retardation 1, 4
• Diuretics are not first-line agents but may be used safely at lower doses in specific circumstances (e.g., chronic kidney disease) 1

Postpartum Care

• Recent developments include improved postpartum monitoring protocols with home blood pressure monitoring (HBPM) and dedicated postpartum hypertension clinics 1
• Early postpartum visits (3-10 days, ideally within 72 hours for high-risk individuals) are recommended, followed by late postpartum visits (6 weeks to 1 year) 1
• Screening for depression, anxiety, and other mental health conditions is critical in the postpartum period, with the Edinburgh Postnatal Depression Scale recommended as a screening tool 1
• Telehealth, including HBPM, can help reduce disparities in postpartum care 1

Future Research Directions

• The field of hypertensive disorders of pregnancy has historically had a limited evidence base, though research has accelerated in recent years 1
• Future research priorities include:
  • Determining optimal treatment thresholds
  • Assessing safety profiles of antihypertensive medications
  • Understanding effects on maternal and neonatal outcomes
  • Examining the effect of tighter BP control in the postpartum period
  • Assessing long-term cardiovascular outcomes 1
• There is a need for harmonization of guideline recommendations across organizations to improve care through consistent messaging to patients and clinicians 1

Pitfalls and Caveats

• Weight reduction is not recommended during pregnancy, even in obese pregnant women, due to risk of reduced neonatal weight and slower subsequent growth 1
• When using nifedipine with magnesium sulfate, caution is needed due to risk of precipitous blood pressure drop 1
• Sodium nitroprusside should be used rarely and only when other treatments fail, as fetal cyanide poisoning may occur if used for more than 4 hours 1
• Labetalol may cause hypotension, bradycardia, hypoglycemia, and respiratory depression in infants of treated mothers 5
• The risk of recurrence of hypertensive disorders in subsequent pregnancies is directly related to the severity of the incident case, gestational age at onset, and medical comorbidities 1