From the Guidelines
Gestational hypertension is primarily caused by abnormal placentation and subsequent maternal vascular dysfunction, as defined by the development of persistent de novo hypertension at or after 20 weeks’ gestation in the absence of features of preeclampsia 1. The condition develops when there is inadequate remodeling of spiral arteries during placental development, leading to placental ischemia and the release of anti-angiogenic factors like soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin. These factors antagonize vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), causing widespread endothelial dysfunction. This endothelial damage results in vasoconstriction, increased vascular resistance, and activation of the coagulation cascade, ultimately manifesting as hypertension after 20 weeks of pregnancy. Some key points to consider in the etiology and management of gestational hypertension include:
- Risk factors: nulliparity, advanced maternal age, obesity, chronic hypertension, diabetes, kidney disease, autoimmune disorders, and previous history of preeclampsia
- Genetic factors: a family history increases risk
- Multiple gestations: create greater placental mass, increasing the likelihood of placental dysfunction
- Management: regular prenatal monitoring of blood pressure and proteinuria, with antihypertensive medications like labetalol, nifedipine, or methyldopa used when necessary to control blood pressure, as recommended by guidelines such as those from the American College of Cardiology/American Heart Association 2 The definitive treatment is delivery, with timing based on gestational age and severity of maternal and fetal conditions. It is also important to note that gestational hypertension can be a precursor to more severe conditions such as preeclampsia, which is characterized by the de novo appearance of hypertension accompanied by significant proteinuria, and can have serious consequences for both the mother and the fetus if not properly managed 3.
From the Research
Etiology of Gestational Hypertension
The etiology of gestational hypertension, also known as pregnancy-induced hypertension, is not fully understood. However, several studies have identified potential risk factors and underlying mechanisms:
- Gestational hypertension is associated with endothelial dysfunction in the mother, prolonged immunological activation, fetal development limitation, hypertension with or without proteinuria, and endothelial dysfunction after week twenty of pregnancy 4.
- Hypertensive disorders in pregnancy, including gestational hypertension, are associated with increased risk of maternal, fetal, and neonatal morbidity and mortality 5, 6, 7.
- The exact cause of gestational hypertension is unknown, but it is thought to be related to a combination of factors, including:
- Chronic hypertension
- Preeclampsia
- Superimposed preeclampsia on chronic hypertension
- Endothelial dysfunction
- Immunological activation
- Fetal development limitation
- Proteinuria
- Gestational hypertension can be classified into four groups depending on the onset of hypertension and the presence of target organ involvement: chronic hypertension, preeclampsia, gestational hypertension, and superimposed preeclampsia on chronic hypertension 6.
Risk Factors
Several risk factors have been identified for gestational hypertension, including:
- Prior history of hypertensive disorders in pregnancy
- Chronic hypertension
- Preeclampsia
- Superimposed preeclampsia on chronic hypertension
- Endothelial dysfunction
- Immunological activation
- Fetal development limitation
- Proteinuria
- Family history of hypertensive disorders in pregnancy
- Obesity
- Age over 35 years
- Multiple pregnancy
Pathophysiology
The pathophysiology of gestational hypertension is complex and involves multiple mechanisms, including:
- Endothelial dysfunction
- Immunological activation
- Fetal development limitation
- Proteinuria
- Hypertension with or without proteinuria
- Endothelial dysfunction after week twenty of pregnancy
- Chronic hypertension
- Preeclampsia
- Superimposed preeclampsia on chronic hypertension
- Activation of the renin-angiotensin-aldosterone system
- Increased vascular resistance
- Decreased vascular compliance
- Activation of inflammatory pathways
Diagnosis and Management
The diagnosis and management of gestational hypertension involve:
- Close monitoring of blood pressure and fetal well-being
- Laboratory evaluation, including proteinuria and liver function tests
- Fetal assessment, including ultrasound and non-stress testing
- Antihypertensive medication, including labetalol, nifedipine, methyldopa, and hydralazine
- Hospitalization for severe cases
- Delivery of the baby as the definitive management of severe pre-eclampsia 5, 6, 7, 8.