What Does an Abdominal Separation (Diastasis) Measurement Actually Tell You?
Answer:
It tells you the width of the gap between your abdominal muscles at the moment it was measured. It doesn’t tell you how well your core is working.
During pregnancy, the two sides of your abdominal muscles stretch apart to make room for your baby. This is called abdominal separation, or diastasis. After birth, a health or fitness professional may measure the gap, often with their fingers.
That number can be useful, but it’s only one small piece of the picture. How your core supports you as you lift, carry and move tells you far more.
How it's measured
There are a few ways to measure the gap.
Fingers. The most common way. A professional presses gently along the middle of your abdomen and counts how many fingers fit in the gap. It’s quick and free, but two people can get different results on the same woman.
Calipers. A measuring tool that gives a number in centimetres. More precise than fingers.
Ultrasound. The most accurate, but not always available.
Each method can give a slightly different result, so a number from one check can’t always be compared with a number from another.
Why your number can change
Your measurement can be different from one check to the next, even when nothing about your body has changed.
That’s because:
Where it’s measured. The gap is often wider at the belly button than above or below it.
Resting or moving. The gap measures differently when you are lying still compared with lifting your head.
Who is measuring. Different people press and count in slightly different ways.
Time since birth. The gap often narrows on its own in the early weeks as hormone levels settle.
There’s also no agreed number for what counts as a diastasis. Studies use different cut-offs, from 2 to almost 3 centimetres. So one person might tell you that you have a diastasis, and another might tell you that you don’t.
How common it is
Abdominal separation is a normal part of pregnancy. One study found that every woman in the study had some separation by 35 weeks.
After birth, the gap narrows for many women without any treatment. Estimates vary because of the measurement differences above, but as a rough guide, about 4 in 10 women still have a separation 6 months after birth, and about 1 in 3 at a year.
What makes it more likely
Some things are linked with a higher chance of separation after birth:
- Having a caesarean
- Previous abdominal surgery
- Having had more than one baby
- Having a bigger baby
Not every study agrees on these, and many women with none of them still have a separation.
What to ask if you're measured
A measurement is more useful when you understand it. You can ask:
- How did you measure it, with fingers, calipers or ultrasound?
- Was I resting or moving when you measured?
- How is my core working when I lift, carry and move?
That last question tells you the most. Instead of “how wide is my gap?”, the more helpful question is “how well is my core supporting me?”
For more on recovery and rebuilding your core, read our articles Can You Heal From Diastasis Completely Without Surgery? – WHEN and Can I Do Sit-Ups After Having a Baby? | WHEN
References
Bigdeli, N., Yalfani, A., Doosti-Irani, A., & Qodrati, A. (2025). An evidence-based comparison of rehabilitation strategies for diastasis recti abdominis in postpartum women: a systematic review and network meta-analysis. Scientific Reports, 15, 39591.
Bixo, L., Sandblom, G., Osterberg, J., Stackelberg, O., Bewo, K., & Olsson, A. (2022). Association between inter-recti distance and impaired abdominal core function in post-partum women with diastasis recti abdominis. Journal of Abdominal Wall Surgery, 1.
de Oliveira, L.C., de Almeida, L.I.M., Lucio, M.C.F., Campos Junior, J.F., & de Oliveira, R.G. (2025). Effects of conservative approaches for treating diastasis recti abdominis in postpartum women: A systematic review and meta-analysis. Medicine, 104(23).
Du, Y., Huang, M., Wang, S., Yang, L., Lin, Y., Yu, W., Pan, Z., & Ye, Z. (2025). Diastasis recti abdominis: A comprehensive review. Hernia, 29.
Gluppe, S.B., Ellstrom Engh, M., & Bo, K. (2023). Curl-up exercises improve abdominal muscle strength without worsening inter-recti distance in women with diastasis recti abdominis postpartum: a randomised controlled trial. Journal of Physiotherapy, 69(3), 160-167.
Mota, P., Pascoal, A.G., Carita, A.I., & Bø, K. (2015). Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain. Manual Therapy, 20(1), 200-205.
Skoura, A., Billis, E., Papanikolaou, D., Xergia, S., Tsarbou, C., Tsekoura, M., Kortianou, E., & Maroulis, I. (2024). Diastasis recti abdominis rehabilitation in the postpartum period: a scoping review of current clinical practice. International Urogynecology Journal, 35, 491-520.
Zhu, Y., Jiang, L., Ye, T., Liu, Y., Sun, L., Xiao, L., Chen, J., Wang, T., Ren, Y., Xu, H., Zhao, H., Mao, X., & Shen, T. (2024). Risk factors and patient-reported outcomes in Chinese women with postpartum diastasis recti abdominis: An observational study. International Journal of Women’s Health, 16, 179-192.
Developed by the WHEN Clinical Team
Clinically reviewed by the WHEN Clinical Governance Committee
Last reviewed: 01/10/2026
With clinical input from Peta Titter, RN, Grad Cert Continence Nursing, Advanced Diploma of Pilates. Honours by Research (diastasis recti). PhD candidate, University of Tasmania. Founder and CEO, WHEN.
