What to know
- A diastasis is a ridge down the middle of the belly that shows up when you sit up. It is not a hernia.
- The two rectus muscles have drifted apart, and the tissue between them is stretched thin. There is no hole, so nothing can get trapped.
- A lump in one spot above the belly button is different. That can be an epigastric hernia, which is a true hernia.
- Physical therapy for the core is the first thing to try. I offer surgery only when a hernia is also present.
A quick summary. The full details are below, and none of it replaces an exam.
What is a diastasis?
A diastasis (say it die AS tuh sis) is also called rectus diastasis or diastasis recti. Two long, flat muscles run down the front of your belly, one on each side, from your ribs to your pelvis. These are the rectus muscles, the “six pack.” In the middle, a strip of tough tissue called the linea alba holds them side by side. In a diastasis, that middle strip has stretched, and the two muscles sit farther apart than normal: more than 2 cm, or about three quarters of an inch.¹
Who gets a diastasis?
Anything that keeps pushing outward on the middle of the belly wall, month after month, can stretch the linea alba. The things studies link to a diastasis:
- Pregnancy. Almost every woman has some separation late in pregnancy as the growing baby raises the pressure inside the belly.³ For many the gap narrows after delivery, but about a third still have it a year later.⁴ More pregnancies, twins, a bigger baby, and more weight gained during pregnancy raise the odds.⁵ ⁹
- Extra weight around the middle. A higher BMI is one of the most consistent risk factors, in women and in men.⁶ ⁷ ⁸ Fat carried inside the belly adds to the pressure pushing on the wall from the inside.
- Diabetes. It shows up as a risk factor in several studies.⁵ ⁶ ⁷
- Age. The tissue of the belly wall weakens with time, and a diastasis becomes more common as we get older.⁷ ⁸
- Frequent heavy lifting. In one study, women who lifted heavy loads 20 or more times a week were about twice as likely to have a diastasis after childbirth.⁴
Men get a diastasis too, most often with extra weight around the middle and with age.⁸
Why does it bulge when I sit up?
When you tighten your belly, like sitting up from lying down, the two rectus muscles pull toward the middle. The thin, stretched tissue between them cannot hold back the pressure inside your belly, so it pushes out. That is the ridge, or tent, you see running down the middle of your belly, usually between the breastbone and the belly button. When you relax, it flattens.
Muscles side by side
The two rectus muscles sit close together, held by a narrow, strong strip of tissue in the middle.
The muscles have drifted apart
The middle strip has stretched wide and thin. Lying still, your belly can look flat.
The ridge appears
Tightening your belly pulls the muscles toward the middle. The thin tissue between them bulges out into a ridge. Relax, and it flattens.
A hernia has a hole. A diastasis does not.
A hernia is an opening in the strong layer of the belly wall (the ) that tissue can push through and get stuck in. In a diastasis, the middle tissue is stretched and thin, but it is still in one piece, so nothing can get trapped. A diastasis is not dangerous and does not need emergency care.
Is it a diastasis or an epigastric hernia?
Above the belly button, a diastasis is easy to mix up with an epigastric hernia. An epigastric hernia is a hole in that same middle strip. Fat from inside the belly pushes through the hole and makes a lump. Unlike a diastasis, it can trap tissue.
A long ridge
Runs down the middle, breastbone to belly button. Shows up when you sit up, gone when you relax.
One lump in one spot
Sits in the middle above the belly button. Often there when you stand, even at rest.
| Diastasis | Epigastric hernia | |
|---|---|---|
| What it is | The two rectus muscles have drifted apart. The middle strip is stretched thin but still in one piece. | A hole in the middle strip. Fat, and sometimes bowel, pushes through it. |
| What you see | A long ridge from the breastbone toward the belly button | A round lump in one spot, sometimes more than one |
| When you see it | Only when you tighten your belly, like sitting up from lying down | Often there when you stand, and bigger when you cough or strain |
| How it feels | Soft, with no edge. Usually not painful. | A firm lump that can be tender, even when it is small |
| Can it get stuck? | No. There is no hole. | Yes. A lump that gets stuck out, hard, and painful is an emergency. |
| Size | Measured as the gap between the muscles. More than 2 cm counts as a diastasis. | Most are under 2 cm, but I also see large ones. |
| Treatment | Physical therapy first. I offer surgery only when a hernia is also present. | Reduced and repaired, often in about 30 minutes for a small one. |
The two can happen together, and a diastasis can also come with an umbilical hernia at the belly button. When the exam is not clear, an ultrasound or CT scan tells them apart.² Read more in the epigastric hernia guide.
What helps how a diastasis looks?
- Physical therapy for your core. A physical therapist can teach you exercises for the deep belly muscles and how to brace them. For many people this improves how the belly looks and feels, and it is the first thing to try.¹ ²
- Get out of bed the easy way. Roll onto your side and push up with your arms instead of sitting straight up. Less straining means less of the ridge while you work on your core.
- Work toward a healthy weight. Less fat inside the belly means less pressure pushing on the thin middle tissue.
- Give it time after pregnancy. The gap often narrows on its own in the first months after delivery.³ ⁴
Do I need surgery for a diastasis?
Most people with a diastasis never need surgery. In rare cases it limits daily life, with a weak, unstable core or a bulge that gets in the way of work or exercise. Even then, physical therapy is the place to start.
I offer surgery for a diastasis only when there is also a hernia. If you have an umbilical or epigastric hernia along with a diastasis, I repair the hernia and address the diastasis in the same operation. If you have a diastasis and no hernia, I do not offer surgery.
Not sure which one you have? Take the 2-minute self-check, or call my office at (817) 250-7030.
References
1. Hernández-Granados P, Henriksen NA, Berrevoet F, et al. European Hernia Society guidelines on management of rectus diastasis. Br J Surg. 2021;108(10):1189-1191. https://doi.org/10.1093/bjs/znab128
2. Carlstedt A, Bringman S, Egberth M, et al. Management of diastasis of the rectus abdominis muscles: recommendations for Swedish national guidelines. Scand J Surg. 2021;110(3):452-459. https://doi.org/10.1177/1457496920961000
3. Fernandes da Mota PG, Pascoal AG, Carita AI, Bø K. Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain. Man Ther. 2015;20(1):200-205. https://doi.org/10.1016/j.math.2014.09.002
4. Sperstad JB, Tennfjord MK, Hilde G, Ellström-Engh M, Bø K. Diastasis recti abdominis during pregnancy and 12 months after childbirth: prevalence, risk factors and report of lumbopelvic pain. Br J Sports Med. 2016;50(17):1092-1096. https://doi.org/10.1136/bjsports-2016-096065
5. Lin S, Lu J, Wang L, et al. Prevalence and risk factors of diastasis recti abdominis in the long-term postpartum: a cross-sectional study. Sci Rep. 2024;14(1):25640. https://doi.org/10.1038/s41598-024-76974-x
6. Cavalli M, Aiolfi A, Bruni PG, et al. Prevalence and risk factors for diastasis recti abdominis: a review and proposal of a new anatomical variation. Hernia. 2021;25(4):883-890. https://doi.org/10.1007/s10029-021-02468-8
7. Wu L, Gu Y, Gu Y, et al. Diastasis recti abdominis in adult women based on abdominal computed tomography imaging: prevalence, risk factors and its impact on life. J Clin Nurs. 2021;30(3-4):518-527. https://doi.org/10.1111/jocn.15568
8. Du Y, Huang M, Wang S, et al. Diastasis recti abdominis: a comprehensive review. Hernia. 2025;29(1):222. https://doi.org/10.1007/s10029-025-03417-5
9. Bruno A, Foti R. When does rectus diastasis worsen the most? A pregnancy-order analysis of midline fascial failure. Aesthetic Plast Surg. 2026;50(15):6497-6511. https://doi.org/10.1007/s00266-026-05997-8