Diagnosis of Gestational Hypertension

Diagnostic Criteria

The American College of Cardiology defines hypertension as a systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg 1, 2
Severe hypertension is defined as a systolic blood pressure ≥160 mmHg and/or diastolic blood pressure ≥110 mmHg 2, 3
The diagnosis of gestational hypertension should be based on at least two elevated readings on two separate occasions 4, 5, 6

For severe hypertension (≥160/110 mmHg), confirmation should be done within 15 minutes with repeated measurements 2, 3, 7
For less severe hypertension, confirmation should be done with repeated readings over several hours on the same visit or on two consecutive antenatal visits 1

The American Heart Association considers hypertension before 20 weeks as chronic hypertension, while new-onset hypertension at or after 20 weeks is considered gestational hypertension 5, 6, 1, 4

To diagnose gestational hypertension, the presence of preeclampsia characteristics should be excluded 5, 6, 3
The European Society of Cardiology recommends evaluating maternal organ dysfunction in asymptomatic women with new-onset hypertension without proteinuria using laboratory tests such as complete blood count, liver enzymes, and serum creatinine 5, 6, 1, 3

Gestational hypertension carries approximately 20% risk of developing preeclampsia 1, 5
The risk of complications depends on the gestational age at which it develops 5, 6
Approximately 25% of gestational hypertension cases progress to preeclampsia 7
Women with gestational hypertension should be monitored more frequently than usual during the remainder of the pregnancy, including home blood pressure measurements 6, 1, 3
Proteinuria should be evaluated at 3 months postpartum 1

Refers to elevated blood pressure in the clinic (≥140/90 mmHg) but normal blood pressure at home or work (<135/85 mmHg) 1
Carries an increased risk of preeclampsia and requires monitoring 1
Ambulatory blood pressure monitoring or home monitoring is recommended before accepting a diagnosis of essential hypertension 1

In pregnant individuals, a gestational age of ≥20 weeks is the pivotal cutoff used to differentiate chronic (pre‑existing) hypertension from pregnancy‑related hypertension; hypertension occurring before 20 weeks is classified as chronic, whereas new‑onset hypertension at or after 20 weeks is classified as gestational hypertension or preeclampsia【8】.
The 20‑week cutoff reflects the expected physiologic decline in blood pressure during the first 20 weeks of a normal pregnancy; deviation from this decline signals a pathologic process【8】.

24‑hour ambulatory average blood pressure in pregnancy is considered normal when <126 mmHg systolic / <76 mmHg diastolic【8】.
Awake‑period average is normal when <132 mmHg systolic / <79 mmHg diastolic【8】.
Asleep‑period average is normal when <114 mmHg systolic / <66 mmHg diastolic【8】.

Pregnant individuals who later develop gestational hypertension often exhibit a blunted decline or an early rise in systolic blood pressure before 20 weeks, contrasting with the typical physiologic decrease seen in uncomplicated pregnancies【8】.
This atypical early‑pregnancy blood‑pressure pattern may serve as an early marker to identify women at higher risk for developing gestational hypertension, allowing for closer surveillance and preventive interventions【8】.