Report this one

Most pages about pregnancy breathlessness reassure you first and add the exceptions at the end. This one has to work the other way round, because the specific symptom in the title is an exception.

The NHS's list of pregnancy symptoms that need help includes it by name: "if breathlessness comes on suddenly, you're out of breath when you're lying down, or you have other symptoms like chest pain or dizziness, this needs to be checked immediately."

Tommy's puts the same symptom on its contact-straight-away list twice over: "You feel out of breath when you are lying flat, and feel you need to sit or stand up to breathe properly" and "You feel as if you can't lie in bed at night and need to sit upright to sleep."

That does not mean something is wrong. It means the assessment is quick, it is routine, and it is not something to schedule around your next appointment.

Why this version is singled out

Ordinary pregnancy breathlessness has a recognisable shape. Tommy's describes it: "Shortness of breath starts gradually in early pregnancy or the second trimester. It should not be painful or come on suddenly. You shouldn't have other symptoms, such as wheezing or a cough."

Breathlessness that changes with body position behaves differently. It is provoked by lying down rather than by effort, it can wake you an hour or two after falling asleep, and it improves when you sit up. That pattern is one of the ways heart and lung problems show themselves, which is why national guidance treats it as a symptom rather than a discomfort.

Tommy's names the conditions it is screening for: anaemia, and "serious conditions called pulmonary embolism, pulmonary oedema or peripartum cardiomyopathy". It then says the important part out loud: "These conditions can sometimes be missed or misdiagnosed. This is because lots of the symptoms are like pregnancy symptoms."

The mechanical explanation, and its limits

There is a benign version of this. Late in pregnancy your uterus reaches the diaphragm, and lying flat lets the weight of your abdomen press upwards, reducing how far your lungs can expand. Plenty of people in the last trimester genuinely cannot get comfortable lying flat and sleep propped on pillows without anything being wrong. Tommy's notes that any breathlessness may ease once the baby's head engages and drops lower.

The limit of that explanation is that you cannot tell it apart from the other causes by feel, and neither can anyone else over the phone. It is a reason not to panic, not a reason not to report.

What the assessment involves

This is the section most pages leave out, and knowing it makes the call easier to make. Tommy's sets out what should happen:

Blood tests to check that you have enough iron, that your organs are working properly, and that your heart is not under too much pressure.
A physical examination that includes checking whether your breathing changes when you are lying down, whether you have a cough or chest pain, and listening to your chest.

Depending on what those show, further tests may follow. The important framing from Tommy's is that "doctors should give you tests to find out why you have these symptoms" — assessment is the expected response, not an over-reaction.

Anaemia is one of the more common explanations, it is found on a blood test, and it is treatable. That alone makes the appointment worth having.

The emergency version

Tommy's lists the symptoms that mean 999 or A&E rather than a phone call to your midwife. Call an ambulance if you have breathlessness together with any of:

Feeling faint and dizzy, or passing out.
Any kind of chest pain.
Coughing up blood.
Heart palpitations — your heart feeling as though it is not beating normally or is beating too fast.
Swelling in one leg.
Feeling as though you are gasping for air, or that breathing is getting harder and harder.

The HSE's equivalent list for a suspected clot on the lung is: chest pain or pain in your upper back, sudden difficulty breathing, pain when you breathe in, or coughing up blood. It adds a line worth knowing: "You can have a PE without symptoms of a DVT." You do not need a swollen calf first.

RCOG's patient information describes the same cluster and gives the instruction attached to it — that these symptoms need immediate help. The NHS also asks you to call 999 rather than drive yourself to A&E if you have symptoms of a clot with chest pain or breathlessness.

What helps at night meanwhile

Once you have been assessed and the mechanical explanation is the one you are left with, the practical measures are the obvious ones, and none of them has trial evidence behind it:

Sleep propped up on several pillows or a wedge rather than flat.
Sleep on your side. The NHS advises avoiding going to sleep on your back after 28 weeks in any case.
A pillow supporting the bump and another between the knees, which stops you rolling flat.
Smaller meals in the evening, since a full stomach adds to the pressure.
Keep the room cool and take stairs slowly.

Report any change. Breathlessness that was manageable and has got noticeably worse is a new symptom, not the same one.

When to call someone

Your midwife or doctor straight away if you are out of breath lying flat, need to sit up to breathe, cannot sleep lying down, have breathlessness that started suddenly or has got much worse in the third trimester, are coughing or wheezing, have swelling in both legs, or are unusually tired (Tommy's).
Your maternity unit immediately if breathlessness comes with chest pain or dizziness (NHS), or if one calf is red, swollen and hot (HSE).
Your local emergency number — 999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand — for breathlessness with chest pain, coughing up blood, palpitations, fainting, one-sided leg swelling, or a sense that breathing is getting steadily harder.
Your midwife at your next appointment, at minimum, for any breathlessness at all. Tommy's advice is that "if you are feeling out of breath during pregnancy you should always mention it".

The short version

Gradual, exertional, painless breathlessness is the ordinary kind. Breathlessness that arrives when you lie down, or that makes you sit up to breathe, is specifically listed by the NHS and Tommy's as needing checking straight away. The assessment is a blood test and a listen to your chest. Chest pain, coughing blood, palpitations or one swollen leg alongside it means an ambulance.

Breathlessness When Lying Down in Pregnancy