creation date: 2025-07-21 14:51
tags: Pathologies
Gestational Hypertension
Background
Definitions
Gestational hypertension refers to hypertension that is induced by pregnancy and resolves postpartum. It is relatively common, complicating roughly 10% of pregnancies.
This condition is part of a group of disorders known as hypertensive disorders of pregnancy, which consist of:
- Chronic hypertension with or without superimposed pre-eclampsia/eclampsia
- Gestational hypertension
- Preeclampsia
- Hemolysis, elevated liver enzyme, and low platelet count (HELLP) syndrome
- Eclampsia
These conditions presents a significant risk of morbidity to both mother and fetus, with the primary concern being the progression to preeclampsia/eclampsia and HELLP syndrome.
Etiology and Pathogenesis
The pathogenesis of hypertension during pregnancy is influenced by a few factors.
Placental malfunction has the largest contribution. Abnormal growth resulting in superficial and partial invasion into the maternal arteries result in high-resistance and thin spiral arteries. Typically, pro-angiogenic factors are lacking and with the reduced angiogenesis, results in ischemia and subsequent oxidative stress. This harms placental cells and releases anti-angiogenic substances and inflammatory cytokines into the maternal bloodstream leading to hypertension.
Endothelial dysfunction leads to a disruption in vascular homeostasis and health. Reactive oxygen species produced from ischemic damage results in downstream vasoconstriction which contributes to hypertension.
In addition to these factors, other components contribute to worsening conditions:
- Immune maladaptation to semi-allogenic fetus
- Genetic and epigenetic factors
- Pre-existing renal pathologies that reduces blood pressure regulatory ability
Clinical Presentation
Signs & Symptoms
As with non-gestational hypertension, gestational hypertension can be asymptomatic and is found incidentally during screening at every prenatal appointment.
Note that gestational hypertension is screened in conjunction with other hypertensive disorders of pregnancy, the signs and symptoms of which are discussed in their respective articles.
History & Physical Exam
Blood pressure measurements should be documented at each prenatal appointment. While diagnoses are made following 20 weeks gestation, measurements made prior to 20 weeks can be used as a baseline.
However, in cases of severe elevations (SBP ≥160 mmHg and/or DBP ≥110 mmHg), wait is not recommended.
History should evaluate for symptoms of preeclampsia which are discussed separately.
Risk factors
Risk factors are similar to preeclampsia:
- Past history of gestational hypertension and/or pre-eclampsia
- Pre-existing diabetes
- Pre-pregnancy overweight or obesity (BMI ≥25 and risk doubles with each 5-7 increase in BMI)
- Chronic kidney disease
- Multifetal pregnancy
- Nulliparity
- Family history of preeeclampsia
- Prior pregnancy complications relating to placental insufficiency
- Advanced maternal age or adolescent pregnancy
- Use of reproductive technology
Diagnosis
Criteria
Diagnosis is made with measurements of
- Systolic blood pressure ≥140 mmHg and/or
- Diastolic blood pressure ≥90 mmHg
on at least two occasions at least four hours apart and diagnosed at ≥20 weeks gestation.
In severe (≥160/110) cases, a 15 minute repeat can be used for confirmation.
Work-up
A urinalysis should be obtained to rule out preeclampsia as proteinuria is the key distinguishing criterion. A dipstick may be sufficient (>2+ protein) but may not be sensitive enough.
Ruling out other causes of hypertension may be considered especially if no blood pressure comparisons are available prior to pregnancy.
Work-up for end-organ damage continues if preeclampsia.
Differential
It is important to differentiate between just gestational hypertension and other more concerning disorders such as preeclampsia, which can cause end-organ damage.
Red Flags / Complications
Complication involves progression to preeclampsia and more severe disorders. 10-50% of patients with gestational hypertension progress to preeclampsia in 1-5 weeks.
Management
Lifestyle / Social
Non-pharmacological component involves patient education which includes:
- Return to office instructions for worsening symptoms
- Home blood pressure monitoring
Optimizing maternal weight gain and exercise may reduce risk of worsening hypertension and/or progression to preeclampsia.
Oral calcium supplementation of <500 mg/day may reduce risk for women with low dietary intake.
Pharmacological / Interventional
Antihypertensives are the cornerstone of blood pressure control. Note that selection differs from nonpregnant patients due to the teratogenic nature of several classes. A target of SBP 130-140 mmHg and DBP of 85-90 mmHg is used for treatment goal.
In severe hypertension, antihypertensives are indicated immediately. Acute therapy can be:
- Labetalol IV 20 mg over 2 minutes, followed at 10 minute intervals by 20-80 mg for a maximum cummulative dose of 300 mg if pressure remains above target
- Hydralazine IV 5 mg over 1-2 minutes, followed by 5-10 mg bolus after 20 minutes prn
- Nifedipine PO intermediate acting (10 mg) or extended release (30 mg)
For maintenance therapy and for milder hypertension (SBP 140-149 mmHg, DBP 90-99 mmHg), a shared decision can be made but is a low threshold for treatment is generally recommended.
- Labetalol 100 mg PO BID (increased by 100 mg each dose every 2-3 days prn up to maximum of 2400 mg total daily dose)
- Nifedipine ER 30-60 mg PO daily (increase at 7-14 days prn up to maximum of 120 mg total daily dose)
- Methyldopa PO
- Hydralazine PO
Some studies have suggested low-dose aspirin may reduce the risk of progression to preeclampsia. However, this is not routine and is generally only indicated for high risk individuals.
Delivery planning is also crucial for hypertensive disorders of pregnancy. For patients with gestational hypertension and no other complications, a 38+0 to 39+0 weeks delivery is recommended for an optimal balance of low maternal and neonatal morbidity/mortality. In more complicated patients (eg. with comorbidities and risk factors), an earlier delivery may be considered (eg. 37+0 weeks).