Hypertensive pregnancy disorders are among the most common medical complications during pregnancy. There are four major types of hypertensive pregnancy disorders. The most common is gestational hypertension, also referred to as (PIH), which occurs after 20 weeks' gestation. Preeclampsia is a form of hypertensive pregnancy disorder with multiorgan involvement. It is characterized by new-onset hypertension and proteinuria after 20 weeks' gestation. Risk factors include nulliparity, a positive family history, and African-American descent. Eclampsia is a severe form of preeclampsia, characterized by new-onset of eclamptic seizures (generalized tonic-clonic seizures). Preeclampsia may also progress to the life-threatening HELLP syndrome, which is characterized by hemolysis, elevated liver enzymes, and low platelet count.
Hypertensive pregnancy disorders are usually diagnosed in the course of regular prenatal care, which includes regular surveillance of blood pressure, weight, and urine tests. Initial treatment for all hypertensive pregnancy disorders consists of maternal and fetal monitoring until delivery is feasible. Antihypertensive treatment (e.g., labetalol, hydralazine) is indicated in severe hypertension. Magnesium sulfate is important to prevent seizures in severe preeclampsia and eclampsia. Patients with eclampsia and HELLP syndrome require immediate stabilization followed by delivery if the pregnancy is ≥ 34 weeks' gestation. Delivery is the only curative option for preeclampsia and eclampsia, which are both associated with increased maternal and fetal morbidity and mortality. HELLP syndrome has a poor fetal prognosis.
These disorders are on a spectrum from less to more severe and occur after 20 weeks' gestation.
- Pregnancy-induced hypertension with onset after 20 weeks' gestation without proteinuria or
- Defined as a systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg on 2 separate measurements at least 4 hours apart
- When hypertension is diagnosed < 20 weeks' gestation, the diagnosis is chronic hypertension and is not due to pregnancy.
- Chronic hypertension: hypertension diagnosed < 20 weeks' gestation or before pregnancy
Preeclampsia: new-onset gestational hypertension with proteinuria or 
- Superimposed preeclampsia: preeclampsia that occurs in a patient with chronic hypertension
- HELLP syndrome
- Occurrence of new-onset hypertension, proteinuria, or at < 20 weeks gestation is suggestive of .
- Eclampsia: a severe form of preeclampsia with convulsive seizures and/or coma
- Postpartum hypertension 
- Hypertensive pregnancy disorders occur in 6–8% of pregnancies. 
Epidemiological data refers to the US, unless otherwise specified.
- Etiology: not fully understood
Risk factors 
- General risk factors
- Pregnancy-related risk factors
Smoking actually decreases the risk of developing preeclampsia. 
Overview: Multiple maternal, fetal, and placental factors are involved in placental hypoperfusion, which leads to maternal hypertension and other consequences.
- Uterine spiral arteries normally develop into high-capacity blood vessels. This process is defective in patients with preeclampsia, which leads to hypoperfusion of the placenta and fetus (see “Placenta” for more information on normal placenta formation).
- Arterial hypertension with systemic vasoconstriction causes placental hypoperfusion → release of vasoactive substances → ↑ maternal blood pressure to ensure sufficient blood supply of the fetus
- Systemic endothelial dysfunction causes placental hypoperfusion → ↑ placental release of factors → endothelial lesions that lead to microthrombosis
- Abnormal placental (or trophoblast) implantation or development in the uterus
Consequences of vasoconstriction and microthrombosis
- Organ ischemia and damage
- Chronic hypoperfusion of the placenta → insufficiency of the uteroplacental unit and fetal growth restriction
|Systemic effects of hypertensive pregnancy disorders|
- Asymptomatic hypertension
- Nonspecific symptoms (e.g., morning headaches, fatigue, dizziness) can occur.
- Onset: ∼ 90% occur after 34 weeks' of gestation.
- Usually asymptomatic
- Nonspecific symptoms may include:
- Severe hypertension (systolic BP ≥ 160 mmHg or diastolic BP ≥ 110 mmHg)
- Proteinuria, oliguria
- Visual disturbances (e.g., blurred vision, scotoma)
- RUQ or epigastric pain
- Cerebral symptoms (e.g., altered mental status, nausea, vomiting, hyperreflexia, clonus)
HELLP syndrome 
- Onset: most commonly > 27 weeks' gestation (∼ 30% occur postpartum)
- Preeclampsia usually present (∼ 85%)
- Nonspecific symptoms: nausea, vomiting, diarrhea
- RUQ pain (liver capsule pain; liver hematoma)
- Rapid clinical deterioration (DIC, pulmonary edema, acute renal failure, stroke, abruptio placentae)
- Onset: The majority of cases occur intrapartum and postpartum.
- Most often associated with severe preeclampsia
- Eclamptic seizures: generalized tonic-clonic seizures (usually self-limited) 
Prenatal screening for hypertensive pregnancy disorders
Early detection to prevent maternal and fetal complications.
- Maternal blood pressure
- Maternal weight
- Maternal urine status (urine dipstick)
- See “ ” for more details.
Initial workup 
- Blood pressure measurement: To diagnose PIH, blood pressure must be elevated on at least 2 occasions that are at least 4 hours apart
- Urine tests
- CBC (RBC, platelets)
- Liver function tests (transaminases)
- Kidney function tests (creatinine)
- Peripheral smear and coagulation studies are indicated if HELLP syndrome is suspected (i.e., thrombocytopenia and/or liver function impairment are present).
- sFlt-1 (soluble fms-like tyrosine kinase 1):PlGF (placental growth factor) ratio 
|Diagnostic criteria for hypertensive pregnancy disorders|
|Preeclampsia||Preeclampsia without severe features|
|Preeclampsia with severe features|| |
|HELLP syndrome|| |
- Ultrasound can assess the following:
Obstetric Doppler ultrasound
- Noninvasive method for monitoring placental and fetal blood flow 
- Used to evaluate the uterine arteries, umbilical arteries, umbilical vein, fetal middle cerebral arteries, fetal aorta, and heart
- Cardiotocography (CTG): used to monitor fetal heart rate and uterine contractions (also called electronic fetal monitor)
Differential diagnosis of eclampsia
- Metabolic disorders (e.g., hypoglycemia, hyponatremia)
- Hemorrhagic stroke
- Ischemic stroke
- Withdrawal syndromes
Differential diagnosis of HELLP syndrome
Acute fatty liver of pregnancy
- Definition: : a rare disease most common in the third trimester; characterized by extensive fatty infiltration of the liver, which can result in acute liver failure
- Epidemiology: 1–3:10,000 cases 
- Etiology: unknown
- Pathophysiology: dysfunction of
- Clinical features
- Laboratory analysis
- Imaging: rule out other diagnoses (e.g., liver hematoma)
- Liver biopsy: confirms the diagnosis but biopsy during pregnancy is associated with a high risk of complications for mother and fetus and should be avoided 
- Treatment: immediate delivery 
Intrahepatic cholestasis of pregnancy
- Definition: a rare disease most common in the third trimester that presents with pruritus, jaundice, and an elevation in serum bile acid concentrations
- Epidemiology: occurs in 0.1–0.2% of pregnancies
- Etiology: multifactorial 
- Clinical features
- Diagnostics 
The differential diagnoses listed here are not exhaustive.
- Initial antepartum evaluation: Assess the maternal and fetal status and the necessity for hospitalization and delivery.
- Hospitalization and delivery indicated if: 
- In all other cases, continue outpatient monitoring 
- Maternal monitoring: (1–2 x/week): blood pressure, urine dipsticks, blood analysis (platelet count, liver enzymes, renal function)
- Fetal monitoring: ultrasound every 3 weeks and NST 1–2 x/week
- Patient education
- Antihypertensive drug therapy for severe hypertension (systolic BP ≥ 160 mmHg or diastolic BP ≥ 110 mmHg)
Hypertensive Moms Need Love: Hydralazine, Methyldopa, Nifedipine, Labetalol
Indications for delivery
- Pregnancy is ≥ 34 0/7 weeks' gestation.
Pregnancy is < 34 0/7 weeks' gestation with maternal or fetal instability.
- Immediate delivery after stabilization (IV magnesium sulfate prophylaxis, antihypertensive drugs, corticosteroids ) if one of the following is present:
- Delivery 24–48 hours after corticosteroid administration and initial stabilization if one of the following is present:
- Procedure: Vaginal delivery should be conducted if possible, but often cesarean delivery is needed for younger gestational age, immature cervix, or poor maternal or fetal condition.
Delivery is the only cure for preeclampsia.
Indicated if pregnancy < 34 weeks and mother and fetus are stable
- Monitor in facilities with maternal and neonatal ICU: 
- Magnesium sulfate infusion for prophylaxis of eclampsia
- Oral antihypertensive treatment of severe hypertension; (see “Treatment” for “Gestational hypertension and preeclampsia without severe features” above)
- Corticosteroids for fetal lung maturity
- Diuretics for pulmonary edema
- Airway management
- Supplemental oxygenation
- Anticonvulsive therapy
- Position patient on left lateral decubitus position to prevent placental hypoperfusion through compression of the inferior vena cava and reduce the risk of aspiration in the mother.
- Expectant management in patients < 34 weeks' gestation to allow time for corticosteroid administration can be considered in select cases, but the safety and benefits of this approach have not been confirmed (see “Expectant management” of “Preeclampsia with severe features” above)
- Delivery: once the mother is stable and seizures have stopped
Delivery is the only cure for eclampsia.
HELLP syndrome 
- Placental abruption
- Cerebral hemorrhage, ischemic stroke
- Acute respiratory distress syndrome (ARDS)
- Acute renal failure
- Hepatic subcapsular hematoma
- Aspiration pneumonia
- Retinal detachment
- Long-term: increased risk for cardiovascular disease, diabetes mellitus, and chronic kidney disease 
- Maternal death 
- Fetal complications: occur due to insufficient placental perfusion
We list the most important complications. The selection is not exhaustive.
The prognosis of hypertensive pregnancy disorders depends on the severity of the condition and the complications that occur. In the majority of cases, the conditions resolve within hours or days after delivery.