Dizziness and fainting in pregnancy

Feeling light-headed or dizzy is common in pregnancy, and while it can be unsettling, it’s usually harmless. Your body is going through big changes to your circulation: pregnancy hormones relax and widen your blood vessels, and it takes time for your blood volume to catch up, which can leave your blood pressure a little lower — especially in the first and second trimesters. That’s why standing up too quickly, or standing for a long time, can leave you feeling woozy.

A few common situations bring it on. Standing up quickly can cause a head-rush as blood pools in your legs. Lying flat on your back, particularly later in pregnancy, lets your uterus press on a major blood vessel and reduce blood flow — which is one reason side-lying is recommended in the third trimester. Low blood sugar from not eating, dehydration, overheating (a hot bath, a stuffy room), and anaemia (low iron) can all contribute too.

Preventing it is mostly about the basics. Get up slowly from lying or sitting, and pause a moment before you walk off. Don’t stand still for long stretches — shift your weight, or sit down. Eat regular meals and snacks to keep your blood sugar steady, drink plenty of water, and avoid getting overheated. From the second trimester, rest and sleep on your side rather than flat on your back. And wear loose, comfortable clothing that doesn’t restrict your circulation.

If you feel faint coming on, sit or lie down straight away before you fall — ideally on your side, or sit with your head lowered towards your knees — until it passes. Fainting is more of a risk to you from the fall itself than anything else, so getting yourself safe quickly is the priority.

Most dizziness is nothing to worry about, but it’s worth getting checked in some situations. See your GP or midwife if you’re fainting (actually passing out), if dizziness is frequent or severe, or if you feel dizzy alongside being very tired and pale — as this can point to anaemia, which is common and easily treated. And contact your maternity unit or call 000 promptly if dizziness comes with chest pain, a racing heart, breathlessness, a bad headache, vision changes, or any vaginal bleeding, as these need a more urgent look.

It’s worth planning around it a little, too, especially if you’ve felt faint before. Try not to stand for long periods in hot or crowded places (public transport, queues and long ceremonies are classic culprits), and if you have to, keep your legs moving and don’t lock your knees. If you feel the warning signs — a wave of heat, ringing ears, tunnel vision, feeling clammy — act on them immediately by getting down low before your body does it for you. And do tell the people around you that this can happen, so they can help you to a seat quickly rather than being caught off guard.

For the everyday head-rush when you stand up too fast, though, be reassured it’s a normal part of your changing circulation. Move slowly, eat and drink regularly, sleep on your side, and sit down the moment you feel woozy.