Blood Pressure in Pregnancy: Complete Guide
Blood pressure is checked at every single antenatal appointment for a reason — it's one of the simplest, quickest ways your midwife has of spotting a problem before it becomes serious. Most readings stay perfectly normal throughout pregnancy, but knowing what the numbers mean, and what changes to flag, helps you feel more in control of your own care.
Why blood pressure is checked so often
Blood pressure is recorded as two numbers: systolic (the higher number, pressure when your heart beats) over diastolic (the lower number, pressure between beats). A reading below 140/90 mmHg is generally considered normal in pregnancy.
- It's a cheap, fast, non-invasive way to screen for pre-eclampsia, a pregnancy-specific condition affecting the blood vessels and organs.
- A single high reading isn't usually a cause for alarm — midwives look at the pattern over time, alongside other signs.
- Blood pressure is checked at booking, then at every subsequent midwife or obstetric appointment, so any upward trend gets caught early.
- Home monitors are sometimes recommended if you have risk factors, so you can track readings between appointments.
What's normal — and what isn't
In early-to-mid pregnancy, blood pressure often runs lower than usual. This is because pregnancy hormones, particularly progesterone, relax and widen blood vessels, which can cause dizziness, light-headedness, or feeling faint, especially when standing up quickly. This is common and usually nothing to worry about — just stand up slowly and stay hydrated.
Higher blood pressure becomes more relevant later in pregnancy. A reading of 140/90 or above, especially when it's a new finding, prompts your midwife to look further:
- A urine sample is checked for protein, which combined with high blood pressure can point towards pre-eclampsia.
- Additional blood tests may be requested to check how your liver and kidneys are functioning.
- You might be asked to come back sooner for a repeat check, or referred to the day assessment unit or obstetric team.
- If pre-eclampsia is confirmed, treatment can include monitoring, medication to control blood pressure, and closer surveillance of you and your baby for the rest of the pregnancy.
Symptoms to report immediately
Alongside routine checks, certain symptoms warrant an urgent call to your midwife or maternity unit, day or night, rather than waiting for your next appointment:
- A severe headache that doesn't ease with paracetamol.
- Visual disturbances — flashing lights, blurring, or spots in your vision.
- Sudden swelling of your face, hands, or feet.
- Pain just below your ribs, particularly on the right side.
- Feeling very unwell or unusually breathless.
These can all be linked to rising blood pressure and shouldn't be left until your next booked appointment.
Frequently Asked Questions
What blood pressure reading is considered normal in pregnancy?
Below 140/90 mmHg is generally considered normal. Many women run lower than this in early-to-mid pregnancy because hormones relax the blood vessels, which can cause dizziness. Your midwife tracks your readings at every appointment and compares them to your booking reading, since a rise from your own baseline matters as much as the absolute number.
Why is my blood pressure checked at every single appointment?
Because it's the fastest way to pick up early signs of pre-eclampsia, a condition that can develop quickly and affect both you and your baby if untreated. Checking regularly means any upward trend is spotted early, often before you'd notice any symptoms yourself, allowing extra monitoring or treatment to start promptly.
What happens if my blood pressure is high at an appointment?
Your midwife will usually check a urine sample for protein and may repeat the blood pressure reading after you've rested. Depending on the result, you could be referred for blood tests or to see an obstetric team the same day. A single slightly raised reading isn't automatically pre-eclampsia, but it does need following up rather than ignoring.
This article is for informational purposes only and does not constitute medical advice. Always consult your midwife, GP, or obstetric team about your own blood pressure readings and symptoms.
Related articles: