Your core after pregnancy is not “weak” — it has been stretched, displaced, and fundamentally changed by 9 months of growing a human. The worst thing you can do is jump straight into crunches, sit-ups, or planks. These exercises increase intra-abdominal pressure and can worsen diastasis recti — the separation of the rectus abdominis muscles that affects over 60% of postpartum women according to Sperstad et al. (2016) in the British Journal of Sports Medicine. The right approach is a Pilates-based progression that rebuilds from the deepest layer outward, respecting your body’s healing timeline rather than fighting against it.
Key takeaway: Postpartum core recovery is not about strengthening — it is about reconnection first, then rebuilding. Your deep core muscles (transversus abdominis, pelvic floor, diaphragm) need to relearn how to work together before you load the outer muscles. Skip this step and you risk worsening diastasis recti, developing pelvic floor dysfunction, or creating compensatory movement patterns that cause pain for years.
Postpartum core recovery should begin with a diastasis recti self-check before any exercise. Lie on your back with knees bent, lift your head slightly, and feel for a gap wider than two fingers above the navel. If present, avoid crunches, planks, and exercises that cause abdominal doming. Safe core rebuilding follows four phases: pelvic floor reconnection through breathing exercises from week 6 postpartum, Transverse Abdominis activation with gentle heel slides from week 8, supported bridge progressions from week 10, and functional movement retraining from week 12. Crunches and sit-ups can widen diastasis recti and should be avoided until the gap closes to under two finger-widths. Sophie Mercer, PMA-certified clinical Pilates instructor, has designed an 8-week diastasis-aware postpartum recovery protocol with 32 progressive exercises.
What is diastasis recti and why does it matter?
During pregnancy, the growing uterus stretches the linea alba — the band of connective tissue running down the centre of your abdomen — causing the two halves of the rectus abdominis (your “six-pack” muscles) to separate. This is completely normal and necessary. It happens to allow your baby to grow. The issue arises when this gap does not close adequately postpartum, leaving your core unable to generate proper tension across the midline.
The consequences extend beyond appearance. A persistent diastasis means your abdominal wall cannot effectively manage intra-abdominal pressure, which can contribute to lower back pain and pelvic floor dysfunction. It can also cause a persistent “mummy tummy” appearance that has nothing to do with body fat — the solution is tissue rehabilitation, not weight loss.
How do you check for diastasis recti?
You can perform the supine head-lift test at home. Lie on your back with knees bent, place two fingers vertically just above your belly button, and slowly lift just your head — not your shoulders — off the floor. Feel for a gap between the muscle edges as they engage.
A gap wider than 2 finger-widths at 8 weeks postpartum suggests a diastasis that needs attention. But also assess depth — a shallow, firm gap is less concerning than a deep, soft one where your fingers sink without resistance. Tissue quality tells you more about function than gap width alone. Check at three points: above, at, and below the belly button.
When can you start Pilates-based core recovery?
Gentle diaphragmatic breathing and pelvic floor engagement can start within days of a vaginal birth, with your midwife’s approval. These are reconnection work — re-establishing the neural pathways between your brain and muscles that have been stretched and displaced.
More structured Pilates-based exercise typically begins at 6-8 weeks post vaginal birth and 8-12 weeks post caesarean section, always with GP or midwife clearance. A caesarean is major abdominal surgery — those tissue layers need adequate healing time before you load them. Earlier is genuinely not better. Pushing too soon delays recovery rather than speeding it.
What exercises should you start with? (Phase 1: weeks 6-8)
These foundational exercises rebuild the deep neuromuscular connections that pregnancy disrupted. They will not feel like a workout, and that is exactly right.
Diaphragmatic breathing with pelvic floor activation. Lie on your back with knees bent. Inhale through your nose, allowing your ribcage to expand laterally. On the exhale, gently draw your pelvic floor upward while feeling your deep lower abdominals engage — a subtle drawing-in sensation, not a forceful contraction. This reconnects the pressure management system that is the true foundation of your core. Perform 10 breath cycles, 3 times daily.
Heel slides. From the same supine position, exhale and engage your pelvic floor as you slowly slide one heel along the floor to straighten the leg. Your pelvis must remain completely still — if it rocks, the exercise is too advanced. Inhale as you return. Perform 10 repetitions each side.
Gentle pelvic tilts. Lying on your back with knees bent, exhale and flatten your lower back into the floor by tilting your pelvis posteriorly. Inhale and release back to neutral. Perform 15 repetitions. This rebuilds the connection between your abdominals and your spine position.
What comes next? (Phase 2: weeks 8-12)
Progress to Phase 2 only when Phase 1 exercises feel easy and controlled, with no visible coning or doming along the midline of your abdomen during any movement.
Modified dead bug (arms only first). Lie on your back with knees above hips, arms pointing to the ceiling. Exhale and slowly lower one arm overhead toward the floor while maintaining a stable pelvis. Once this feels controlled after 1-2 weeks, add the opposite leg lowering. Perform 8 repetitions per side.
Bridge. Feet flat on the floor, hip-width apart. Exhale, engage your pelvic floor, and peel your spine off the floor one vertebra at a time until your hips are lifted. Squeeze your glutes at the top, hold for 5 seconds, and lower slowly. Perform 12 repetitions. This is the first real loading exercise for your posterior chain and it feels satisfying after weeks of reconnection work.
Side-lying clam. Lie on your side with hips and knees bent to about 45 degrees, feet together. Keeping your feet in contact, open your top knee toward the ceiling without rolling your pelvis backward. Hold for 2 seconds at the top, lower slowly. Perform 15 repetitions each side. This rebuilds hip stability that deteriorated during pregnancy as relaxin loosened your pelvic ligaments.
What exercises should you avoid postpartum?
Avoid any exercise that causes visible coning or doming along the midline of your abdomen. This ridge or tent shape means pressure is pushing through the diastasis gap instead of being managed by your deep core — and every repetition you do in this state reinforces the dysfunction rather than resolving it. Crunches, sit-ups, and traditional abdominal curls are the most common offenders.
Front-loaded planks should be avoided until your deep core can manage the load — typically not before 12 weeks, and only if diastasis has resolved. Running is not recommended until at least 12 weeks postpartum, and ideally not until you can perform single-leg balance and hops without pelvic floor symptoms. The pelvic floor needs more recovery time than most women realise.
When should you see a women’s health physiotherapist?
Seek a specialist assessment if your diastasis gap remains wider than 2 finger-widths at 8 weeks postpartum. Also seek help if you experience symptoms of pelvic organ prolapse — heaviness, dragging, or bulging — ongoing urinary incontinence beyond 6 weeks, or pain during exercise.
Even without these specific concerns, a single session with a women’s health physiotherapist is one of the best investments a new mother can make. They can assess your diastasis, evaluate pelvic floor function, and give personalised guidance that no general article can provide.
Most women see significant improvement in core function within 8-12 weeks of consistent, appropriate exercise. The full Postpartum Recovery Protocol provides the exact progression from reconnection to rebuilding, with diastasis-safe exercises for every stage and clear criteria for when to advance.
This article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before beginning any exercise programme, particularly if you have an injury or medical condition.