Hypertensive Disorders of Pregnancy (HDP) & Pre-Eclampsia

Hypertensive Disorders of Pregnancy (HDP) are among the leading causes of maternal and fetal complications worldwide — responsible for nearly 18–20% of maternal deaths globally according to WHO (2025).
They include four main types of high blood pressure conditions that occur during pregnancy, and pre-eclampsia is the most dangerous among them.

Types of Hypertensive Disorders in Pregnancy

Type	Description	Timing
Chronic Hypertension	High blood pressure present before pregnancy or before 20 weeks of gestation	Before / early pregnancy
Gestational Hypertension	BP ≥140/90 mm Hg that develops after 20 weeks without protein in urine	Second half of pregnancy
Pre-eclampsia	BP ≥140/90 mm Hg after 20 weeks plus proteinuria (protein in urine) and/or organ dysfunction	Usually 20+ weeks
Eclampsia	Pre-eclampsia with seizures or coma	Late pregnancy / postpartum

Pre-Eclampsia: The Most Critical HDP

Pre-eclampsia is a complex disorder involving the placenta, blood vessels, and immune system.
It can progress suddenly and unpredictably — even in women with no prior hypertension.
It affects both the mother and fetus, and if untreated, can lead to eclampsia (seizures), HELLP syndrome, organ failure, and stillbirth.

Pathophysiology – What Happens in the Body

Abnormal placental development:
- In early pregnancy, the placental blood vessels fail to remodel properly.
- This leads to reduced blood flow and oxygen to the placenta.
Placental stress:
- Damaged placental cells release inflammatory substances into the mother’s bloodstream.
Systemic inflammation & endothelial dysfunction:
- Causes blood vessel constriction, leaky capillaries, and high blood pressure.
Organ damage:
- Kidneys, liver, and brain may be affected — leading to proteinuria, swelling, headaches, and visual changes.

Who Is at Higher Risk

First-time mothers
Age <18 or >35 years
Family or personal history of pre-eclampsia or hypertension
Multiple pregnancy (twins, triplets)
Obesity (BMI > 30)
Diabetes or gestational diabetes
Kidney disease or autoimmune disorders (like lupus)
Short (<1 year) or long (>10 years) gap between pregnancies

Symptoms to Watch For

Pregnant women should seek urgent care if any of these occur:

Persistent headache (not relieved by rest or medication)
Swelling of face, hands, or feet (sudden or severe)
Blurred vision or flashing lights
Upper abdominal pain (right side, under ribs)
Nausea, vomiting, or shortness of breath
Rapid weight gain (due to fluid retention)

These may appear in the second half of pregnancy or even postpartum (within 6 weeks after delivery).

Effects on the Baby

Restricted fetal growth (IUGR) due to poor blood supply
Preterm birth (to protect the mother’s health)
Low birth weight
Stillbirth or neonatal death (in severe untreated cases)

Diagnosis & Monitoring

Blood Pressure Monitoring:
- ≥140/90 mm Hg on two occasions (at least 4 hours apart)
Urine Test:
- Protein in urine (>300 mg/24 h or +1 dipstick)
Blood Tests:
- Check liver enzymes (AST/ALT), kidney function (creatinine, uric acid), platelet count
Ultrasound:
- Monitor baby’s growth, amniotic fluid, and placenta
Fetal Heart Rate Monitoring to detect distress

Management & Treatment

Depends on Severity and Gestational Age:

1. Mild Pre-Eclampsia (BP 140–159/90–109 mm Hg):

Regular monitoring at hospital or home
Rest, hydration, and reduced salt intake
BP medications (as prescribed)
Close fetal growth surveillance

2. Severe Pre-Eclampsia (BP ≥ 160/110 mm Hg or organ dysfunction):

Hospital admission
IV antihypertensives (labetalol, hydralazine)
Magnesium sulfate to prevent seizures
Steroids to mature fetal lungs if early delivery expected
Delivery is the only definitive cure once the baby is viable (≥34 weeks or earlier if mother/fetus at risk)

3. Post-Delivery Care:

Monitor BP for up to 12 weeks postpartum
Some women develop chronic hypertension later in life, requiring long-term follow-up.

Recent Global Trends

Rising Incidence: HDP cases have increased by 15–20% worldwide, according to Frontiers in Global Women’s Health (2025).
Climate & Stress Factors: Heat, pollution, and psychosocial stress are now recognized as aggravating HDP triggers.
Genetic & Microbiome Research: New studies are exploring placental DNA and gut bacteria links to pre-eclampsia risk.
AI & Early Prediction:
- Machine learning models can now predict pre-eclampsia risk from early pregnancy blood pressure, weight, and biomarkers.
- Digital monitoring devices track BP at home for early alerts.

Prevention Strategies

Aspirin Therapy:
- Low-dose aspirin (75–150 mg) after 12 weeks can reduce pre-eclampsia risk in high-risk women (as per WHO & ACOG guidelines).
Calcium Supplementation:
- 1.5–2 g/day calcium helps lower risk in areas with low dietary calcium.
Healthy Lifestyle:
- Maintain normal weight before and during pregnancy.
- Eat balanced diet rich in fruits, vegetables, and lean proteins.
- Avoid excessive salt, smoking, and alcohol.
Regular Antenatal Visits:
- Frequent BP and urine checks to detect early warning signs.

Public Health Importance

In low- and middle-income countries, pre-eclampsia contributes heavily to maternal deaths and preterm births.
WHO urges that every antenatal program includes BP monitoring and public education on warning symptoms.
Improved equity and access to quality obstetric care can drastically reduce preventable maternal deaths.

“Pre-eclampsia is not fully preventable, but early detection and timely management can save both lives.”
— World Health Organization, 2025 Maternal Health Bulletin

Summary

Aspect	Impact
Condition	High BP & organ dysfunction during pregnancy
Main Threat	Pre-eclampsia → Eclampsia → Maternal & Fetal death
Detection	BP, urine, blood tests, ultrasound
Treatment	BP control, magnesium sulfate, early delivery
Prevention	Low-dose aspirin, calcium, regular checkups
Outcome	Excellent with early diagnosis & medical supervision

Hypertensive Disorders of Pregnancy (HDP) & Pre-Eclampsia