Why it happens

The NHS describes it exactly as most people experience it: "You might be unable to prevent a sudden spurt of pee when you cough, laugh, sneeze, move suddenly or just get up from a sitting position." Its explanation is that "the pelvic floor muscles (the muscles around the bladder) relax slightly to prepare for the baby's delivery".

Add the mechanical part — a growing uterus sitting directly on the bladder, particularly once the baby's head is low — and you have a bladder with less capacity supported by a floor that is doing less work than it used to. The NHS calls incontinence "a common problem during and after pregnancy" and notes it "may be temporary".

None of that makes it something to put up with in silence. It has a treatment with guidance behind it, which is more than can be said for most pregnancy symptoms.

Two things to rule out first

Is it urine or is it amniotic fluid?

This is the question that matters most, and it is not always obvious. The NHS describes amniotic fluid as "clear and pale", possibly "a little bloodstained to begin with", arriving as "a slow trickle or a sudden gush of water you cannot control". Its instruction if your waters break is to call your midwife, and to "use a period pad (not a tampon) so your midwife can check the colour of the waters".

Useful differences: urine has a smell and amniotic fluid does not; leaking urine happens with a trigger such as a cough and then stops; amniotic fluid keeps coming, often more when you stand up, and does not stop when you tighten your pelvic floor. If you are in any doubt, phone. Being checked and told it was urine is a five-minute conversation. The alternative is not.

Before 37 weeks, any fluid loss you cannot confidently explain is a same-day call.

Is it an infection?

The NHS is direct: "If you have any pain while peeing or you pass any blood in your pee, you may have a urine infection, which will need treatment." Its advice is to drink plenty of water to dilute your urine and to "contact your GP within 24 hours of noticing these symptoms". Urinary infections are more common in pregnancy and are treated rather than tolerated.

Sudden new urgency, needing to pee constantly with only small amounts coming, cloudy or strong-smelling urine, or a temperature all point here rather than to the pelvic floor.

What actually works

NICE's guideline on pelvic floor dysfunction, NG210, is unusually clear for a pregnancy symptom, and its recommendations are worth quoting rather than paraphrasing.

For prevention: "Encourage women who are pregnant or who have recently given birth to do pelvic floor muscle training, and explain that it helps prevent symptoms of pelvic floor dysfunction."

For treatment, the recommendation is stronger than most people realise: "Offer a programme of supervised pelvic floor muscle training for at least 3 months to women (including pregnant women) with stress urinary incontinence or mixed urinary incontinence." Offer is NICE's word for something that should be provided, not merely mentioned. And NG210 specifies that "pelvic floor muscle training programmes should be supervised by a physiotherapist or other healthcare professional with the appropriate expertise".

NICE also suggests considering a three-month supervised programme from week 20 of pregnancy for women who have a first-degree relative with pelvic floor dysfunction — a mother or sister with prolapse or incontinence is a reason to start early rather than wait for symptoms.

So the practical action is: tell your midwife you are leaking, and ask to be referred to a pelvic health physiotherapist. That referral exists.

How to do the exercises

The NHS's instructions are specific, and technique matters more than effort:

Find the muscles by imagining stopping yourself peeing and passing wind.
Squeeze the pelvic floor muscles quickly, trying not to pull your tummy in.
Hold for 2 seconds, then relax.
Repeat 10 times, breathing normally throughout.
Gradually build the hold up towards 10 seconds.

The NHS is honest about the timescale: "You may have to do pelvic floor exercises for a few months before you see any benefits." That is a reason to start now rather than a reason not to bother.

Things that make leaking worse

From the NHS's advice on managing a weak bladder, the parts that apply in pregnancy:

Constipation. "Straining to poo weakens your pelvic floor muscles and makes urinary incontinence worse." Never ignore the urge to go.
Smoking, because coughing strains the pelvic floor.
Lifting. Tighten the pelvic floor before and during any lift you cannot avoid.
High-impact exercise. Swapping running for lower-impact strengthening work can reduce leaks.

The NHS's general incontinence advice also includes losing excess weight. That advice is not for pregnancy — deliberate weight loss while pregnant is a conversation to have with your midwife, not something to act on from a general page.

What not to do

Do not cut down on drinking. It concentrates your urine, irritates the bladder and raises the risk of infection. Do not use a tampon to manage leaking. And do not wait until after birth to mention it — NICE notes that symptoms starting in pregnancy carry an increased risk of getting worse during it and persisting afterwards, which is precisely why it is worth treating now.

When to call someone

Your midwife or maternity unit straight away if you cannot tell whether the fluid is urine or your waters, if there is a gush, or if fluid keeps coming without a trigger — especially before 37 weeks (NHS).
Your GP within 24 hours if you have pain when you pee or blood in your urine (NHS).
Your midwife to ask for referral to a pelvic health physiotherapist, which NICE says should be offered for stress or mixed incontinence.
Your maternity unit if you develop a temperature, tummy pain or back pain alongside urinary symptoms.
Your GP or midwife if you have any new difficulty starting to pee, cannot pee, or lose sensation around your bottom or genitals — that combination is urgent and unrelated to ordinary leaking.

The short version

Leaking with a cough or a sneeze is common in pregnancy and has a proper treatment: supervised pelvic floor muscle training for at least three months, which NICE says should be offered rather than suggested. Before you settle on that explanation, be sure it is urine and not amniotic fluid, and that there is no infection underneath it.

Leaking Urine in Pregnancy