Severe Gestational Hypertension

Severe gestational hypertension is new blood pressure of 160/110 mmHg or more after 20 weeks, without proteinuria or other features of preeclampsia. It is classed with severe disease because the maternal and perinatal risks match those of severe preeclampsia. Some develop preeclampsia within weeks.

• Risk factors: first pregnancy, obesity, twin pregnancy, family history, previous gestational hypertension.
• Treat at once to lower the risk of stroke.
• Delivery decisions follow severity and gestation.

Women are usually well, with sustained severe blood pressure found at routine visits, sometimes with headache. No proteinuria or end organ injury is found at first.

• Blood pressure 160/110 mmHg or more twice, 15 minutes apart.
• Normal reflexes.
• Differential diagnosis: preeclampsia, chronic hypertension, white coat hypertension, kidney disease, phaeochromocytoma, drug effect.
• Complications: progression to preeclampsia, eclampsia, stroke, abruption, HELLP syndrome, fetal growth restriction, preterm birth, stillbirth.

The diagnosis needs severe readings after 20 weeks with no proteinuria and normal blood tests.

• Blood pressure on two readings 15 minutes apart with a correct cuff.
• Urine protein to creatinine ratio (below 30 mg/mmol), full blood count, creatinine, liver enzymes, lactate dehydrogenase, uric acid, glucose.
• Ultrasound for growth and umbilical artery Doppler; cardiotocography.
• Repeat blood tests twice weekly because proteinuria may develop.

The principle is urgent blood pressure control, close surveillance and delivery at 34 weeks or sooner for severe disease.

• Supportive: admit; rest; blood pressure every 15 minutes during treatment, then 4-hourly; daily fetal movement counts; urine protein measured twice weekly.
• Pharmacological: nifedipine immediate release 10 mg oral, repeated once after 30 minutes if needed, or labetalol 20 mg IV over 2 minutes then 40 mg, 80 mg and 80 mg at 10 minute intervals (maximum 220 mg), or hydralazine 5 mg IV then 5 to 10 mg every 20 to 30 minutes (maximum 20 mg); then maintenance labetalol 200 mg oral every 8 to 12 hours (maximum 2.4 g daily) or nifedipine modified release 30 to 60 mg oral once daily (maximum 120 mg) or methyldopa 250 to 500 mg oral 8-hourly (maximum 3 g daily), aiming for 110 to 135/85 mmHg; magnesium sulphate 4 g IV over 20 minutes then 1 g per hour for 24 hours if headache, visual change, epigastric pain, clonus or laboratory abnormality appears; aspirin 150 mg oral at night until 36 weeks; betamethasone 12 mg IM twice, 24 hours apart, before 34 weeks; oxytocin 10 IU IM after birth, avoiding ergometrine.
• Procedures: delivery at 34 weeks if severe hypertension persists, earlier for preeclampsia, uncontrolled hypertension or fetal compromise; induction with misoprostol 25 micrograms vaginal 6-hourly (maximum 4 doses) or Foley catheter with oxytocin.
• Special groups: asthma uses nifedipine instead of labetalol; diabetes needs insulin adjustment with steroids.
• Red flags: headache, visual change, epigastric pain, seizure, new proteinuria, platelets below 100 x 10^9/L, reduced fetal movements.
• Follow-up: blood tests twice weekly; growth scans every 2 weeks; postnatal blood pressure at 6 hours, daily for 5 days, then at 2 and 6 weeks; review at 6 weeks.