Gestational Hypertension

New-onset hypertension (systolic ≥140 mmHg and/or diastolic ≥90 mmHg) after 20 weeks gestation, without proteinuria or other features of pre-eclampsia, distinguished from chronic hypertension (pre-existing or diagnosed before 20 weeks) and from pre-eclampsia itself. Up to 15 to 25% progress to pre-eclampsia, which is why ongoing surveillance is essential rather than a one-time diagnosis.

Mild disease (140 to 159/90 to 109 mmHg): close monitoring with weekly to twice weekly BP and urine protein checks
Treatment threshold BP ≥140/90 mmHg (per NICE, treating to a target below 135/85 mmHg): first line labetalol 100 to 200 mg PO bd-tds (maximum 2400 mg/day); alternatives nifedipine modified release 10 to 20 mg PO bd (maximum 90 mg/day), or methyldopa 250 to 500 mg PO tds-qds (maximum 3 g/day), the latter less favored now given CNS side effects but with long-standing safety data
Severe hypertension (≥160/110 mmHg) is managed as an emergency, following the same approach detailed under Pre-eclampsia below
Increased surveillance for progression to pre-eclampsia
Delivery by 40 weeks if uncomplicated and well controlled; earlier if worsening

Referral: obstetric-led care; escalate urgently if pre-eclampsia features develop.

Clinical toolsCalculators

BMI GCS EDD Parkland Formula

Corrected Sodium Corrected Calcium Anion Gap Creatinine Clearance Insulin Calculations qSOFA Wells PE Wells DVT CHA₂DS₂-VASc HAS-BLED CURB-65 Centor/McIsaac

Oligohydramnios

Reduced amniotic fluid volume for gestational age.

Causes include placental insufficiency and FGR (fluid reduction reflects reduced fetal renal perfusion and urine output as a compensatory response to hypoxia), premature rupture of membranes, post-term pregnancy, fetal renal or urinary tract anomaly (particularly bilateral renal agenesis or obstructive uropathy, causing severe, early oligohydramnios), and certain maternal medications (notably ACE inhibitors/ARBs and NSAIDs in the third trimester).

Treat or address the underlying cause where identifiable: stop causative medications (ACE inhibitors/ARBs, NSAIDs), manage PPROM per that entry
Increased fetal surveillance with serial growth scans, Doppler, and CTG, given the association with placental insufficiency and increased risk of cord compression in labor
Amnioinfusion (instillation of fluid into the amniotic cavity, either antenatally or intrapartum via an intrauterine catheter) may be used in selected cases to reduce cord compression related fetal heart rate decelerations in labor, or, in specific research and specialist settings, to allow improved visualization for detailed anatomy scanning
Delivery timing individualized by gestation, severity, and the underlying cause, generally earlier delivery is favored where oligohydramnios reflects significant placental insufficiency with FGR
Severe, early, structural (renal) oligohydramnios carries a guarded prognosis and requires detailed counseling with fetal medicine and, where relevant, neonatology and pediatric urology input

Referral: fetal medicine specialist for significant or early-onset oligohydramnios, particularly where a structural fetal cause is suspected.

Gestational Hypertension

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management