Pregnancy-Induced Hypertension

Although the true incidence of PIH remains unknown, it is believed to complicate about 6–10% of pregnancies, contributing to one of the major causes of maternal, fetal, and neonatal mortality and morbidity.

Short-term maternal risks: CNS dysfunction, hepatocellular injury/hemorrhage, thrombocytopenia, acute DIC, oliguria, pulmonary edema, cerebrovascular events (hemorrhage, encephalopathy), placental abruption, acute renal failure, progression to PEC, or EC and death.

Short-term fetal risks: Severe intrauterine growth restriction, small for gestational age, preterm birth, low birth weight, oligohydramnios, hypoxia-acidosis, neurologic injury, and intrauterine and perinatal death.

Prompt recognition: When PIH is complicated by PEC, EC, or superimposed forms

Timely response: With pharmacologic treatment or delivery of fetus/placenta when crucial

High risk of uteroplacental insufficiency despite elevated maternal BP

Multiple organ/system-based complications associated with PIH (see Assessment Points table)

Broadly defined as BP ≥140/90 mm Hg obtained on at least two occasions at least 4 h apart. PIH is further classified into four categories:

Chronic Htn: Htn before pregnancy, noted <20 wk gestation (suspect if Htn persists beyond 6 mo postpartum)

Gestational Htn: BP >140/90 but <160/110 mm Hg after 20 wk gestation in previously normotensive pt. Increased BP in the first 24 h postpartum but normalization of BP within 10 d; no proteinuria, no other associated symptoms, no abnormal lab findings/blood tests

PEC-EC:

• PEC: Htn at ≥20 wk gestation + proteinuria (≥300 mg protein in 24-h urine collection)

• PEC with severe features: Htn at ≥20 wk gestation + any of the following (new onset): Severe Htn (BP ≥160/110 mm Hg); persistently severe cerebral or visual disturbances; thrombocytopenia, <100,000/mm ³ ; HELLP syndrome; elevated liver enzymes, >2× upper limit normal; pulm edema; serum creatinine, >1.1 mg/dL; or doubling serum creatinine (in the absence of other renal disease)

Superimposed PEC:

• Superimposed PEC: Exacerbation of previously controlled CHTN (escalating BP meds) and/or new-onset/increased proteinuria

• Superimposed PEC with severe features: Exacerbation of previously controlled CHTN despite treatment with severe features/symptoms (cerebral/visual changes, persistent epigastric pain, pulm edema, and lab findings, as discussed previously)