What Happens to Your Core During Pregnancy and Birth?
Pregnancy places extraordinary demands on the abdominal region. As the uterus expands, the abdominal muscles — particularly the rectus abdominis (the "six-pack" muscle) — stretch and separate at the midline to accommodate the growing baby. The pelvic floor muscles, which support the weight of the abdominal organs, experience prolonged pressure and may sustain stretching or micro-trauma during vaginal delivery.
After birth, whether vaginal or by caesarean section, many women are left with a core that feels weak, disconnected, or simply unfamiliar. This is entirely normal — but it does mean that returning to exercise requires a thoughtful, phased approach rather than jumping straight back to pre-pregnancy routines.
Understanding Diastasis Recti
Diastasis recti (DR) refers to the separation of the two halves of the rectus abdominis along the linea alba — the connective tissue that runs down the midline of the abdomen. Some degree of abdominal separation is present in the vast majority of women at full term. For many, this resolves naturally in the weeks after birth; for others, the gap or the tensional integrity of the linea alba remains compromised.
Signs that may indicate diastasis recti include:
- A visible ridge or "coning" down the centre of the belly when doing a sit-up or crunch
- A soft, domed feeling at the midline when engaging the abdominals
- A feeling of core weakness disproportionate to effort
- Lower back pain or pelvic instability
It's worth having a women's health physiotherapist assess for DR before beginning any abdominal rehabilitation programme.
Phase 1: The First 6 Weeks — Rest and Reconnection
In the first six weeks postpartum, the priority is rest, healing, and gentle reconnection with your body. This is not the time for intensive exercise, regardless of how you feel. Your uterus is involuting, internal tissues are healing, and — if you had a caesarean — you have a significant internal wound to recover from.
Safe activities in this phase:
- Diaphragmatic breathing: Reconnects you to the deep core and stimulates healing through improved circulation. Practice lying down, 5–10 minutes daily.
- Gentle pelvic floor contractions: Start these as soon as it is comfortable — even within the first 24 hours for vaginal births. Hold for 3–5 seconds, release fully, and repeat 10 times.
- Short, gentle walks: Begin with just a few minutes and gradually increase as energy and comfort allow.
Avoid in Phase 1: Sit-ups, crunches, heavy lifting, high-impact activity, and any exercise that causes coning or doming at the midline.
Phase 2: Weeks 6–12 — Building Foundations
After your six-week postnatal check and clearance from your healthcare provider, you can begin to gently load the core. This phase focuses on building a strong foundation before progressing to more demanding exercises.
Key exercises for Phase 2:
- Dead bugs: Lie on your back with knees at 90 degrees. Slowly extend one arm and the opposite leg toward the floor while exhaling. Return and repeat. Keep your back flat and avoid any midline bulging. (8–10 reps per side)
- Glute bridges: Lie on your back, feet flat on the floor. Exhale and lift your hips until your body forms a straight line from knees to shoulders. Hold briefly, inhale as you lower. (10–12 reps)
- Bird dogs: From hands and knees, extend the opposite arm and leg while maintaining a stable pelvis. (10 reps per side)
- Standing wall presses: Stand facing a wall with hands on the surface. Inhale, then exhale and gently push through your hands while engaging your core — a gentle, functional activation. (10 reps)
Phase 3: Months 3–6 — Progressive Strengthening
As your core becomes more stable and your pelvic floor stronger, you can progress to more challenging exercises and begin reintroducing activities like swimming, cycling, and Pilates. Impact activities (running, jumping) are generally recommended only after pelvic floor readiness has been assessed — often around 12 weeks minimum, but frequently later.
Signs you are ready to progress:
- No leaking with coughing, sneezing, or jumping
- No pelvic heaviness or pressure during activity
- Core can maintain neutral spine during moderate exertion
- No pain during or after exercise
The Role of a Women's Health Physiotherapist
A women's health physiotherapist (also called a pelvic health physiotherapist) can assess both the pelvic floor and abdominal wall with far greater precision than any general guide can offer. An assessment at around 6–8 weeks postpartum is a worthwhile investment — it can identify issues early, reassure you when things are healing well, and set you on the right path for your individual recovery.
A Note on Patience
Recovery is not linear, and comparison to others — or to social media timelines — is rarely helpful. Your body grew and birthed a human being. It deserves care, time, and compassion. The goal is not to "bounce back" but to build forward: toward a strong, functional, healthy core that serves you for decades to come.