White Coat Hypertension in Pregnancy

White coat hypertension in pregnancy is raised blood pressure (140/90 mmHg or more) in the clinic with normal readings at home or on 24 hour monitoring (below 135/85 mmHg). It reflects an alerting reaction to clinical staff. It is common among women with raised clinic readings and carries a lower risk than true hypertension, but some develop gestational hypertension or preeclampsia.

• Risk factors: anxiety, first pregnancy, obesity, previous white coat hypertension.
• Avoids unnecessary drugs and admissions.
• Needs ongoing surveillance.

Women are well, with raised readings only in the clinic, no proteinuria and normal examination. Home readings are normal.

• No symptoms.
• Normal urine protein and blood tests.
• Differential diagnosis: gestational hypertension, chronic hypertension, preeclampsia, masked hypertension, wrong cuff size, pain or anxiety.
• Complications: progression to gestational hypertension or preeclampsia, unnecessary drug exposure and admission.

The diagnosis is confirmed by out of clinic readings.

• Home blood pressure for 7 days: two readings morning and evening, with an average below 135/85 mmHg; or 24 hour ambulatory blood pressure monitoring with a daytime average below 135/85 mmHg.
• Validated upper arm device and correct cuff size.
• Urine protein to creatinine ratio, full blood count, creatinine, liver enzymes, uric acid.
• Ultrasound for growth at 28 to 32 weeks; uterine artery Doppler at 20 to 24 weeks.

The principle is no antihypertensive drug, with home monitoring and prompt reassessment if readings rise.

• Supportive: reassure; teach correct home measurement; record readings twice daily; review at each antenatal visit with a repeat of the clinic measurement after 5 minutes of rest; avoid caffeine before visits.
• Pharmacological: none for blood pressure; aspirin 150 mg oral at night from 12 weeks to 36 weeks if other risk factors for preeclampsia exist; calcium 1.5 g elemental oral daily where intake is low; if home readings reach 140/90 mmHg or more start 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).
• Procedures: none; delivery follows obstetric indications at 40 weeks, with induction at 41 weeks.
• Special groups: asthma uses nifedipine instead of labetalol if treatment becomes necessary; women with twin pregnancy or diabetes have a lower threshold to treat and monitor.
• Red flags: home readings of 140/90 mmHg or more, headache, visual change, epigastric pain, new proteinuria, reduced fetal movements.
• Follow-up: antenatal review every 2 weeks from 28 weeks with urine protein; growth scan at 32 weeks; postnatal blood pressure at 6 hours and at 2 and 6 weeks; annual blood pressure after pregnancy.