Pregnancy-induced hypertension (PIH) is a condition characterized by high blood pressure that develops after the 20th week of gestation in a previously normotensive woman. It is diagnosed when the systolic blood pressure reaches 140 mmHg or higher, or the diastolic blood pressure reaches 90 mmHg or higher, recorded on two separate occasions at least four hours apart. Unlike chronic hypertension, which is present before pregnancy or diagnosed before 20 weeks, PIH resolves postpartum, typically within twelve weeks after delivery. Nurses must monitor blood pressure routinely during antenatal visits because PIH can progress rapidly to more severe conditions like preeclampsia.
The core physiological defect in pregnancy-induced hypertension involves abnormal trophoblastic invasion of the maternal spiral arteries. Instead of widening to accommodate increased blood flow, these vessels remain narrow and high-resistance. This results in placental ischemia, releasing inflammatory factors and free radicals into the maternal circulation. These circulating toxins cause widespread endothelial dysfunction, leading to vasoconstriction, increased vascular permeability, and platelet activation across multiple organ systems.
Hypertensive disorders in pregnancy encompass a spectrum of conditions with varying degrees of severity and risk. Clinicians categorize them into distinct types to guide appropriate monitoring and treatment strategies.
Certain maternal characteristics increase the likelihood of developing pregnancy-induced hypertension. Nulliparity is a well-established risk factor, as first-time pregnancies carry a higher incidence. A personal or family history of preeclampsia significantly elevates risk due to potential genetic predispositions. Medical conditions such as chronic renal disease, pre-existing diabetes mellitus, and vascular disorders predispose women to endothelial damage. Advanced maternal age over 40 years, multifetal gestation, and high body mass index also contribute to the overall etiological profile.
Comprehensive assessment involves tracking maternal blood pressure trends, checking urine for protein using dipsticks or 24-hour collections, and screening for subjective symptoms like severe frontal headaches, visual disturbances, and epigastric pain. Laboratory evaluations assess liver enzymes, serum creatinine, and complete blood counts for thrombocytopenia. Fetal well-being is evaluated through serial ultrasound scans to monitor growth, biophysical profiles, and Doppler velocimetry of the umbilical artery to detect placental compromise early.
Management strategies depend on gestational age and disease severity. For women without severe features near term, delivery is the definitive treatment to prevent maternal complications. In preterm cases, expectant management involves close monitoring, antihypertensive medications such as labetalol or nifedipine to control blood pressure, and corticosteroids to accelerate fetal lung maturity. Nurses maintain accurate intake and output records, enforce bed rest in a left lateral position to improve placental perfusion, and administer prescribed medications safely.
When preeclampsia escalates to severe features or eclamptic seizures occur, immediate emergency interventions are vital. Magnesium sulfate is the drug of choice for seizure prophylaxis and control, administered via an infusion pump with strict monitoring of deep tendon reflexes, respiratory rate, and urine output. Antihypertensive therapy using IV labetalol or hydralazine is initiated rapidly to lower dangerously high blood pressure and prevent stroke. The nursing team ensures a patent airway, administers oxygen, and prepares for emergency delivery once the mother is stabilized.
Pregnancy-induced hypertension poses severe risks to both mother and baby if left unmanaged. Maternal complications include placental abruption, disseminated intravascular coagulation, acute renal failure, cerebral hemorrhage, and HELLP syndrome, which involves hemolysis, elevated liver enzymes, and low platelet count. Fetal complications stem primarily from chronic hypoxia and placental insufficiency, resulting in intrauterine growth restriction, preterm birth, and stillbirth. Long-term prognosis is generally favorable after delivery, though women who experience PIH face a higher lifetime risk of developing chronic hypertension and cardiovascular disease.