What diastasis recti is

Two bands of muscle run vertically down the front of your abdomen, joined in the middle by a strip of connective tissue called the linea alba. As the uterus grows, that strip stretches and thins, and the two muscle bands move apart.

The HSE describes it precisely: "As your baby grows during pregnancy, the tissue stretches. This stretched tissue is thinner and can feel like a gap in the middle of the muscle."

The NHS makes the crucial point about how common it is: "It's common for the 2 muscles that run down the middle of your stomach to separate during pregnancy — usually about 2 finger widths. This is called diastasis recti, or divarication." The HSE goes further: "This gap is normal in pregnancy."

It is not an injury, and it is not something you caused by lifting wrong or having a big baby. It is what happens when an abdomen accommodates a full-term pregnancy.

How to check it

Both the NHS and the HSE describe the same self-test.

Lie on your back with your knees bent and your feet flat on the floor.
Raise your head and shoulders slightly off the floor and look down at your tummy.
Using your fingertips, feel between the edges of the muscles, above and below your belly button. The HSE suggests turning your fingers sideways to feel the width of the gap.
Note how many fingers fit in the gap, and repeat every so often to see whether it is narrowing.

The HSE's threshold: "If you can fit more than 2 fingers between the muscles, there are some things you can do to help reduce the gap." It also adds a caveat that matters: "If you had a caesarean, wait until at least 5 weeks after giving birth. This is because your scar needs time to heal."

Depth is arguably more informative than width. A gap you can feel but that has firm tension across it behaves very differently from one where your fingers sink in easily. That is not something the national guidance quantifies, which is a fair reflection of how imprecise finger-width measurement actually is.

What is normal, and what timeline to expect

The two national sources give slightly different windows, and both are worth knowing.

The HSE: "It can take up to 6 weeks after the birth for the gap to reduce. But sometimes it can take longer." The NHS: "The separation between your stomach muscles will usually go back to normal by the time your baby is 8 weeks old."

Take those as a guide rather than a deadline. What matters more than the calendar is whether the gap is getting smaller and whether you have symptoms.

When to call

Contact your GP if:

the gap is still obvious 8 weeks after the birth. The NHS says to contact the GP at this point "as you may be at risk of back problems"
you are still worried about the gap after 8 weeks. The HSE's advice is to "ask your GP for a physiotherapy referral"
you have abdominal pain or discomfort. The NHS notes that "some women also have abdominal pain or discomfort"
you have back pain that is not settling, or a feeling of instability through your middle

The NHS is explicit about the route: "The GP can refer you to a physiotherapist, who will give you some specific exercises to do." A women's health or pelvic health physiotherapist is the right specialist here, and in some areas you can refer yourself directly.

Get urgent advice if you have severe abdominal pain, a firm painful lump you cannot push back in, or pain with vomiting — those are not diastasis recti and need assessing.

What actually helps

Be sceptical of anything sold with a promise to "close the gap" by a fixed date. Here is what national guidance actually supports.

Pelvic floor and deep abdominal work. The NHS: "Regular pelvic floor and deep stomach muscle exercises can help to reduce the size of the separation between your stomach muscles." NICE's pelvic floor guideline (NG210) encourages women who have recently given birth to do pelvic floor muscle training, and recommends considering a supervised three-month programme after an assisted vaginal birth, a back-to-back birth, or an anal sphincter injury.
The NHS's specific exercise. Lie on your side with knees slightly bent; let your tummy relax and breathe in; as you breathe out, "gently draw in the lower part of your stomach like a corset, narrowing your waistline"; squeeze your pelvic floor at the same time; hold for a count of 10, breathing normally, then release. Repeat up to 10 times.
Posture. The NHS: "It's also important to stand up tall and be aware of your posture."
Breathing. The HSE: "Try not to hold your breath when bending, lifting and exercising. This is a bad habit some people get when their tummy muscles are weak."
Support garments. The HSE says a binder or compression top "can help narrow the gap for up to 8 weeks after the birth." Useful as short-term support, not as a substitute for training the muscles.

On what to avoid, the NHS is direct: "Try to avoid exercises such as sit-ups, planks and high-impact exercises to start with. Also avoid straining on the toilet and heavy lifting."

Note that national guidance is not unanimous here. The HSE includes crunches and Russian twists in its own suggestions, while advising anyone who had a caesarean not to do them until 12 weeks. If you are unsure which applies to you, that disagreement between two national health services is a perfectly good reason to ask a physiotherapist rather than an app.

Why it is worth bothering

Not for the way your stomach looks. The reasons the guidance gives are functional: the NHS links a persistent gap to a risk of back problems, and ACOG notes that postnatal back, neck and joint pain can be caused by "strain on your back muscles, abdominal muscle weakness, and hormone changes during and after pregnancy", sometimes warranting a referral to a physical therapist.

A weak middle also makes everything else in early parenthood harder, because lifting a car seat out of a boot is a core exercise whether you programmed it or not.

What to let go of

A gap you can still feel at eight weeks is common and is a reason to get assessed, not a failure. Very few abdomens return to their exact pre-pregnancy configuration, and function — can you lift, carry, and move without pain? — matters far more than finger-widths.

Diastasis Recti After Pregnancy