Low BP in Pregnancy: Causes, Dizzy Spells and Red Flags
Blood pressure tends to fall in the first half of pregnancy, so a lower reading can be expected, but fainting or bleeding needs medical help. This guide sets out what counts as low, which dizzy spells are mild, and which signs mean you call for help straight away.
Quick facts
- Low reading: less than 90/60 mmHg, by the NHS definition.
- Early pattern: blood pressure tends to fall during the first half of pregnancy.
- High in pregnancy: 140/90 to 159/109 mmHg is classed as hypertension, by the NHS definition.
- Call 999: if you are pregnant and bleeding and feel faint, dizzy or sick, or if the bleeding is heavy.
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What counts as low blood pressure in pregnancy?
The NHS defines low blood pressure as a reading of less than 90/60 mmHg. Its guidance lists being pregnant among the causes, and the symptoms it names are dizziness and fainting. Symptoms matter most. A number alone tells you less than the symptoms that come with it.
When does blood pressure usually fall in pregnancy?
During the first half of pregnancy, the NHS says, blood pressure tends to fall, so a lower number early on is the usual pattern, and the question worth asking is whether that lower reading comes with any of the symptoms listed below. This guide will not add a reason of its own.
How is low BP different from high BP in pregnancy?
The two problems are opposites. High readings usually give no warning. The NHS defines high blood pressure in pregnancy as a reading between 140/90 and 159/109 mmHg, and says high blood pressure does not usually make you feel unwell. Pre-eclampsia is a pregnancy condition that causes high blood pressure, which is why a dizzy spell is never a reason to skip a blood pressure check, even when you feel fine and the reading seems ordinary.
Which dizzy spells are mild, and which need help?
NHS advice for low blood pressure centres on standing up slowly and eating small, frequent meals. A brief wobble is what those steps are meant to prevent. That might follow getting up too quickly, or a long gap between meals. Dizziness that comes with any of the following is not a wait-and-see moment:
- Bleeding, especially heavy bleeding, with feeling faint, dizzy or sick. Call 999.
- Shortness of breath with chest pain or dizziness. This needs checking immediately, and 999 if it is life-threatening.
- A severe headache that does not go away with simple painkillers, or sudden vision problems such as blurred vision or seeing flashing lights.
- Sudden swelling of the face, hands or feet, pain below the ribs, or feeling very unwell.
Fainting matters, and so does repeated dizziness. The NHS advice is to see a GP if you keep getting dizziness and fainting, and it is worth telling your midwife too, so keep a note of when each spell happens.
What should you do in the first few minutes of a dizzy spell?
- Sit down before anything else, and stay sitting until the feeling settles.
- When you stand up again, get up slowly from sitting to standing, as the NHS advises.
- Drink some water. The NHS low blood pressure advice is to increase the amount of water you drink.
- If you have not eaten for a while, have a small snack, then keep meals small and frequent through the day. Sitting still for a while after eating may also help.
- Check the warning signs above. If any apply, call your maternity unit, or 999 if bleeding comes with dizziness or faintness.
- Note the time, the reading if you have a machine, and what you felt, then tell your midwife or GP.
The two-stage stand
After a meal or a long sit, stand up in two stages. First move to the edge of the chair or bed and sit for a moment, then stand. This turns the NHS advice to get up slowly into a habit you can repeat without thinking about it.
At the first wobble, many families reach for sugar water or a salty drink, and grandmothers often insist on a rest. A drink of water and a rest are the parts the NHS advice supports. Salt is different. Adding it to treat a low reading is a question for your midwife, because high blood pressure is also a pregnancy concern and needs checking.
Should you add salt or change your diet for low BP?
Ask your midwife before you add salt. The NHS page on high blood pressure in pregnancy is a reminder that readings can run high as well as low, so any change to salt should be made with your care team. For food, the NHS advice is small, frequent meals and plenty of water through the day. For a full food plan, the desi pregnancy diet chart covers iron, folate and calcium by katori.
How do home BP checks fit in?
A home machine may help you spot a pattern, but only if you note when each reading was taken and how you felt. Ask your midwife which reading should prompt a call, and follow the machine’s instructions. The method is set out in our guide to checking BP at home the right way.
Could something other than blood pressure be the cause?
Yes. Dizziness has several causes, and a low reading is only one of them. The chakkar, dil ghabrana and causes guide goes through the common ones, so you can compare what you feel with the list.
Questions about low BP in pregnancy, answered
What is low BP in pregnancy?
Low blood pressure is a reading of less than 90/60 mmHg, according to the NHS, and being pregnant is one of the listed causes. The symptoms that matter most are the ones that come with the reading.
Is low BP in pregnancy dangerous?
The answer depends on the symptoms. Mild dizziness on its own is often eased with water, slow standing and small meals, but repeated dizziness or fainting needs a GP’s review. Bleeding, shortness of breath with chest pain or dizziness, or a severe headache need prompt help.
Is it normal for BP to drop in early pregnancy?
Yes. The NHS says blood pressure tends to fall during the first half of pregnancy. A lower number early on is the usual pattern.
What are the symptoms of low BP in pregnancy?
The NHS names dizziness and fainting among the symptoms of low blood pressure. If you keep getting them, it advises seeing a GP.
Can I stand up quickly if my BP is low?
It is better not to. The NHS advice is to get up slowly from sitting to standing, and to sit still for a while after eating.
What should I eat for low BP in pregnancy?
The NHS advice is small, frequent meals, with more water through the day. A full food plan is a separate step, and the desi pregnancy diet chart is a good place to start.
Should I add salt to raise my BP?
Ask your midwife first. Readings can run high in pregnancy too, and the NHS regards high readings as something to check, so salt is not a home fix to start on your own.
Which pre-eclampsia signs need urgent help?
The signs are a severe headache that does not go away with simple painkillers, vision problems such as blurred vision or flashing lights, pain below the ribs, sudden swelling of the face, hands or feet, and feeling very unwell. Call your maternity unit, or NHS 111 if you cannot reach it.
Does dizziness with chest pain mean low BP?
Not necessarily. Shortness of breath with chest pain or dizziness needs checking immediately, whatever the blood pressure reading is, and it needs 999 if it is life-threatening.
Can I check my BP at home in pregnancy?
Ask your midwife or doctor first, and ask which reading should prompt a call. Then note the times you check and how you felt.
Call 999 if you are pregnant, bleeding, and feel faint, dizzy or lose consciousness, or if the bleeding is heavy. Shortness of breath with chest pain or dizziness needs checking immediately, and 999 if it is life-threatening. For a severe headache that does not settle, sudden vision changes, sudden swelling, pain below the ribs or feeling very unwell, call your maternity unit. If you cannot reach one, call NHS 111. If dizziness and fainting keep happening, tell your GP or midwife. If you take blood pressure medicine, do not start, stop or change it yourself; ask the doctor who prescribed it.
Bottom line
Treat dizziness as a prompt. The NHS describes a fall in blood pressure during the first half of pregnancy as the usual pattern, so sit, drink, eat and get up slowly. Bleeding with dizziness, breathlessness with chest pain or dizziness, a severe headache, sudden vision change or sudden swelling is a reason to call, not to wait. For the wider picture, the low blood pressure guide covers low readings at other times, and the Diabetes & Blood Pressure hub brings the rest together.
A low reading early on can be expected; dizziness with bleeding, breathlessness or a bad headache is not a wait-and-see moment.