Postpartum core exercises: rebuilding your core after birth

The first postpartum core exercises aren't crunches. They're pelvic floor squeezes, a gentle deep stomach exercise and small movements like pelvic tilts, done while you're still learning to sleep in 90-minute shifts. Bigger work comes later, in stages, once your pelvic floor and abdominal wall can handle it. Less dramatic than a 30-day ab challenge. Much better supported.

Everything here comes from the NHS, ACOG, the WHO and the postnatal return-to-running guideline by physiotherapists Tom Goom, Gráinne Donnelly and Emma Brockwell. When you want the rest of the week planned, an AI coach that builds your plan around your week can do that part.

Before you start: check with your doctor, midwife or a pelvic health physiotherapist before doing any postnatal abdominal exercises, especially after a caesarean or complicated birth. Nothing here is medical advice or a diagnosis.

What postpartum core exercises are actually for

Your core's job after birth is to manage pressure when you lift, cough, carry and eventually run. The NHS notes that your lower back and core abdominal muscles may be weaker than they used to be after birth (NHS). The goal is getting that system working again, not changing how your stomach looks, and nothing here promises a particular result.

It's the foundation for lifting your baby now, and later for a full training week, like a lifting plan for women that brings squats and deadlifts back in stages. Why strength matters more over the decades is in a guide to strength training for women over 40.

What the guidance says about postnatal abdominal exercises

• ›ACOG says exercise routines may be resumed gradually after pregnancy as soon as medically safe, depending on the mode of delivery and any medical or surgical complications, and that pelvic floor exercises can be started in the immediate postpartum period (ACOG, 2020).
• ›The NHS says that after a straightforward birth you can start gentle exercise such as walking, gentle stretches and pelvic floor exercises as soon as you feel up to it, and that after a more complicated delivery or a caesarean you should talk to your midwife, health visitor or GP before anything strenuous (NHS).
• ›The WHO recommends regular physical activity for postpartum women without contraindication, including muscle-strengthening activity, starting small and building gradually. It adds that pelvic floor muscle training may be done daily to reduce the risk of urinary incontinence (Bull et al., 2020).
• ›The return-to-running guideline recommends that every woman, however she gave birth, gets a pelvic health assessment with a specialist physiotherapist to check the abdominal and pelvic floor muscles (Goom, Donnelly & Brockwell, 2019).

Separated stomach muscles (diastasis recti)

The NHS says it's common for the two muscles that run down the middle of your stomach to separate during pregnancy, usually by about 2 finger widths. This is called diastasis recti, or divarication, and the separation will usually go back to normal by the time your baby is 8 weeks old (NHS).

It's common. In a Norwegian study that followed 300 first-time mothers, a separation of at least 2 finger widths was found in 60.0% of women at 6 weeks after birth and 32.6% at 12 months, and women with and without it reported the same amount of lumbopelvic pain at 12 months (Sperstad et al., 2016).

How to check

The NHS self-check: lie on your back with knees bent and feet flat, lift your shoulders slightly off the floor, and use your fingertips to feel how many fingers fit between the muscle edges above and below your belly button. Repeat regularly to check the gap is getting smaller. If it's still obvious 8 weeks after the birth, the NHS says to contact your GP, who can refer you to a physiotherapist. The self-check is a screen, not a diagnosis.

What exercise can and can't do for a gap

The NHS says regular pelvic floor and deep stomach muscle exercises can help to reduce the size of the separation. The research reviews are more cautious about how much:

• ›A 2021 systematic review found very low-quality evidence to recommend any specific exercise program for treating diastasis recti after birth (Gluppe, Engh & Bø, 2021).
• ›A 2023 meta-analysis of 16 trials found abdominal exercise led to a small reduction in the gap, but not a clinically significant one, while noting it may have other physical and psychosocial benefits (Benjamin et al., 2023).
• ›A 2025 review of 65 studies found low-certainty evidence that abdominal training reduced the gap more than no exercise (Beamish et al., 2025).

The return-to-running guideline frames the goal differently: not closing the gap at all costs, but managing pressure and load across the abdominal wall. It says a mother can return to running with a diastasis if it's functional, meaning the separation is present but she has strategies to control that load. Honest summary: core work is worth doing, a physio should guide it, and nobody can promise what it does to the gap.

A postpartum core workout, stage by stage

The return-to-running guideline's Appendix 2 gives an example of exercise progression for the first 3 months (Goom, Donnelly & Brockwell, 2019). The authors say plans vary with your birth experience and any issues. Here are the core-related parts:

Pelvic floor exercises

The NHS routine for after birth (NHS):

• ›Squeeze and draw in your bottom as if holding in wind, and squeeze around your vagina and bladder as if stopping the flow of urine.
• ›Long squeezes: hold for as long as you can, but no longer than 10 seconds, then relax.
• ›Short squeezes: squeeze quickly and let go straight away, until the muscles tire.
• ›Build up to 10 repeats of each, at least 3 times a day, lying down, sitting or standing.
• ›Breathe normally, and don't pull your stomach in when you squeeze.

The deep stomach exercise

Also from the NHS: lie on your side with your knees slightly bent, let your stomach relax and breathe in gently. As you breathe out, gently draw in the lower part of your stomach like a corset while squeezing your pelvic floor. Hold for a count of 10, breathing normally, then release. Repeat up to 10 times.

Pelvic tilts, drop-outs and side-lying leg raises

The guideline's basic core examples for weeks 0 to 2. On your back with knees bent, a pelvic tilt gently flattens and releases your lower back, and a bent-knee drop-out lowers one knee slowly to the side while the pelvis stays still.

A sample postpartum ab workout

This is an illustration, not a prescription. It shows a short early-weeks session for someone whose care provider has agreed to gentle exercise. The NHS sets the first two doses; the rest are a common starting point your physio should adjust.

From around 2 to 4 weeks in the guideline's example, bridges, squats and lunges join in. Keep breathing throughout, and stop if anything brings on heaviness, leaking or pain.

What about crunches, sit-ups and planks?

Not forever, and not first.

The NHS says to try to avoid sit-ups, planks and high-impact exercise to start with if your stomach muscles have separated, and to avoid straining on the toilet and heavy lifting too (NHS). Its page on urinary leaks adds that high-impact exercise and sit-ups put pressure on your pelvic floor muscles and can increase leaks (NHS).

ACOG, meanwhile, says abdominal strengthening exercises, including crunches and the drawing-in exercise, have been shown to decrease the incidence of diastasis recti and the gap between the muscles (ACOG, 2020). Read together, that's a sequencing question, not a contradiction: harder abdominal work has a place once a pelvic health physiotherapist has checked how your abdominal wall and pelvic floor handle load. The return-to-running guideline lists doming or sinking at the midline during load tests as a sign of failed load transfer, which is the kind of thing a physio checks.

Signs to stop and get help

The return-to-running guideline lists signs that make seeing a pelvic health physiotherapist especially important, quoted word for word (Goom, Donnelly & Brockwell, 2019):

• ›"Heaviness/ dragging in the pelvic area (can be associated with prolapse)"
• ›"Leaking urine or inability to control bowel movements"
• ›"Pendular abdomen or noticeable gap along the midline of your abdominal wall"
• ›"Pelvic or lower back pain"
• ›"Ongoing or increased blood loss beyond 8 weeks postnatal that is not linked to your monthly cycle"

It also says: "Heaviness, dragging, incontinence or moderate to severe pain may suggest excessive training distance or intensity." The guideline calls these problems "common but not normal". Nothing to be embarrassed about. Nothing to train through.

Where this fits

After a caesarean the timeline is slower, and working out after a caesarean covers it separately. The rest of the first year is laid out in a postpartum workout plan. If you're still pregnant, pregnancy workouts and third trimester exercise cover the months before. Core work done then is useful, not a pass to skip the early stages after.

How exrsz handles this

exrsz builds a periodized plan from your goal, schedule, level and equipment, balances running and lifting in one plan, adapts each week to how you actually trained, and reshuffles missed sessions, which with a newborn is most of them. It doesn't assess your pelvic floor or your abdominal wall. Check with your doctor, midwife or a pelvic health physiotherapist first, then build from where they say you are.

FAQ

When can I start postpartum core exercises?

After a straightforward birth, the NHS says you can start gentle exercise, including pelvic floor exercises, as soon as you feel up to it (NHS). ACOG says pelvic floor exercises can begin in the immediate postpartum period (ACOG, 2020). After a caesarean or complicated birth, check with your midwife or GP first.

What are the best postnatal abdominal exercises to start with?

The NHS suggests pelvic floor exercises and a side-lying deep stomach exercise (NHS), and the return-to-running guideline's early examples include pelvic tilts, bent-knee drop-outs and side-lying leg raises (Goom, Donnelly & Brockwell, 2019).

Can I do crunches in a postpartum ab workout?

Not to start with if your stomach muscles have separated: the NHS suggests avoiding sit-ups and planks at first (NHS). A pelvic health physiotherapist can tell you when harder abdominal work makes sense for you.

Will a core workout for post pregnancy close a diastasis recti gap?

Not reliably. A 2023 meta-analysis found abdominal exercise produced only a small reduction in the gap, not a clinically significant one, though it may have other benefits (Benjamin et al., 2023). If the gap is still obvious at 8 weeks, the NHS says to contact your GP.