There is a persistent myth that pregnancy means nine months of sitting on the sofa. The opposite is true. Moderate exercise throughout pregnancy is associated with less back pain, a lower risk of gestational diabetes and pre-eclampsia, better sleep, and a stronger pelvic floor going into labour.
What you should not do is train through a pregnancy as though it were not happening. The rules change by trimester, and after birth the rules change again. This guide walks through all of it — with the caveat that your midwife, doctor or physiotherapist outranks anything written on the internet, including this.
Read this first
This article is general information, not medical advice.
Always clear your exercise plan with your midwife, GP or consultant — particularly if you have a high-risk pregnancy, placenta previa, pre-eclampsia, a history of miscarriage or preterm birth, pelvic floor dysfunction, or any pain during pregnancy. In the UK, your NHS pregnancy keeping-well guidance is the most reliable starting point.
The good news: exercise is encouraged
Current guidance from the American College of Obstetricians and Gynaecologists and UK bodies such as the Royal College of Obstetricians and Gynaecologists is that at least 150 minutes of moderate activity per week is safe and beneficial in an uncomplicated pregnancy.
That figure sounds intimidating if you have never exercised. It does not have to mean the gym. A brisk 25-minute walk five times a week meets it comfortably.
The talk test
The standard throughout pregnancy is the "talk test" — you should be able to hold a conversation while training, but not sing. If you are gasping, you are working too hard for this stage. Cardiovascular intensity genuinely needs to drop as pregnancy progresses, and that is normal, not a loss of fitness.
First trimester (weeks 1–13)
The first trimester is often the trickiest, because most women are not training at all before pregnancy — and now they are dealing with fatigue and nausea on top of a new routine.
What is fine
- Walking, swimming, gentle cycling, and low-impact aerobics.
- Continuing any strength work you were already doing, at reduced load.
- Yoga and Pilates, avoiding deep twists, hot yoga, and any position lying flat on your back after week 20.
What to reduce or drop
- Contact risk. In the first trimester, illness is more likely to knock you over. Avoid crowded gyms and indoor swimming pools; outdoor swimming is generally fine.
- Deep core loading. No heavy loaded planks, sit-ups, or hanging leg raises. The core is already under strain and there is no benefit to overloading it.
- Supine (on your back) exercise. Once you are past 20 weeks, lying flat can compress the vena cava. Use incline or side-lying instead.
On lying on your back
The "avoid your back after 20 weeks" advice is a reasonable precaution, not an emergency. If you feel lightheaded, nauseated or short of breath lying flat, roll to your side immediately. Propped incline positions work fine.
Second trimester (weeks 14–27)
This is usually the sweet spot. Energy returns for most women, the belly is not yet in the way, and training at this stage is associated with the best birth outcomes of any trimester.
What to add
- Strength work remains your highest-value tool. Lifting loads builds the functional strength you need for birth, and reduces pregnancy-related back pain.
- Hip hinge and squat variations, performed with a wider stance as the bump grows.
- Pelvic floor work — see below.
- Cardio with a lower centre of gravity: the elliptical, a stationary bike, swimming, or incline walking.
Pelvic floor: the single most useful exercise
Up to one in three women develop pelvic floor dysfunction during pregnancy or after birth. It is one of the few conditions where a few minutes of daily work genuinely prevents the problem rather than treating it.
How to do it: think of stopping the flow of urine mid-stream, or holding back wind — but never actually practise it while urinating, once only, as a check. Breathe out, squeeze and lift for up to ten seconds, then fully relax for ten seconds. Ten repetitions, three times a day. That is the whole thing.
The most common mistake is holding your breath. A pelvic floor contraction should be a gentle upward lift paired with an exhale. Bearing down is the opposite of what you want, and over-trying can make things worse rather than better.
Third trimester (weeks 28–40)
Less about building fitness now, and more about staying comfortable, mobile and confident for birth. Most of my clients in this trimester are training two or three times a week rather than five, and that is exactly right.
What to prioritise
- Hip mobility — deep squat holds, side lunges, and hip circles to prepare for the mechanics of birth.
- Breathing practice. Diaphragmatic breathing with a long exhale is genuinely useful during labour.
- Upper body and posture work, to offset the forward head and rounded shoulders that come with a growing bump.
- Light lower body work — squats, bridges and rows, with an emphasis on the movement quality rather than the load.
- Ankle mobility, since swelling in the third trimester frequently restricts ankle range and a tight ankle worsens balance.
What to avoid
- Exercises involving lying flat on your back.
- Deep squats and heavy lifting that requires a big brace — the core is already under significant strain.
- Anything requiring a hard valsalva (holding your breath and bearing down).
- Contact and fall-risk activities, which rise sharply in the third trimester.
- Overheating — hot yoga, and any environment where your core temperature gets too high.
Warning signs to stop immediately
Stop exercising and contact your midwife or doctor — or call 999 if severe — if you experience any of these during a session:
| Sign | What to do |
|---|---|
| Vaginal bleeding | Stop and contact your midwife the same day |
| Severe abdominal or pelvic pain | Stop and seek urgent advice |
| Dizziness or feeling faint | Lie on your side, hydrate, and stop for the day |
| Shortness of breath before exertion | Stop and contact your midwife |
| Amniotic fluid leaking | Stop and call your maternity unit immediately |
| Regular painful contractions | Stop and contact your midwife |
| Calf pain or swelling | Stop — this can indicate a blood clot |
| Chest pain | Stop and call 999 |
| Fluid leakage, headache or visual changes | Stop and contact your midwife urgently — these can signal pre-eclampsia |
The first six weeks after birth
This is the period most women get wrong — usually by doing far too much, far too early, out of guilt or sheer enthusiasm. Your body has just done something enormous, and rushing past recovery costs you.
Days 1–3: movement only
Short, frequent walks. Everything else can wait. Get outside once or twice daily if you can — it helps mood, sleep and circulation more than any exercise session.
Weeks 1–2: build daily movement
Gradually increase walking duration. Add gentle pelvic floor and transverse abdominis work. Nothing that demands your abdominal wall to bear load yet.
Weeks 3–6: gentle core reintroduction
Breathing drills, small heel slides, and very light loading if you feel ready. Introduce overhead lifting only if you have had an uncomplicated vaginal birth and feel no heaviness or doming in the abdominals.
Week 6: the postnatal check
Your six-week check is the point at which a medical professional clears you for a return to structured exercise. Treat it as a genuine gate, not a formality.
Rest is not laziness. It is what makes the next six months possible. The women who crash in week three because they felt guilty are the ones who end up injured at month nine.
Faiza - Founder, Flex Fitness
Caesarean recovery differs
After a caesarean you have had major abdominal surgery. Timeline everything above by your own healing rather than by a fixed number, and get explicit clearance before loading the abdominals. Scar tissue and tissue mobility work can be helpful, but it needs to be introduced gently and ideally with guidance.
Diastasis recti — the honest version
Diastasis recti is a common widening of the connective tissue between your abdominal muscles. It affects an estimated 60–70% of women postpartum to some degree, and is not the dramatic "gap" that internet content often describes.
It is not a muscle tear, and it cannot be closed by doing crunches — in fact, repeatedly loading a poorly managed gap often makes it worse. The evidence for what does help is strongest for three things: breathing retraining, deep core activation, and gradual loading to encourage the tissue to respond. For anything beyond a mild gap, an assessment by a women's health physiotherapist is the highest-value money you can spend postpartum.
Returning to strength training
Once you are cleared, the priorities in order are:
- Rebuild the foundations. Breath, deep core, pelvic floor. These are not a warm-up you skip; they are the base everything else sits on.
- Load the posterior chain. Glutes and hamstrings take a great deal of strain during birth, and they are often the last thing to come back. Prioritise hip hinges, rows and squats.
- Rebuild your overhead capacity. Especially if you have a baby on your hip or in your arms several hours a day.
- Then progress load. Adding weight, not adding sessions, is what makes you strong. Three good sessions a week beats six poor ones.
- Get your nutrition right. This is where most postnatal programmes fail. If you are breastfeeding, do not restrict calories.
On postnatal weight loss
Weight loss while breastfeeding reduces milk supply and leaves you exhausted — the opposite of what you want. Your nutrition approach at this stage should be about adequate energy, protein and micronutrients, not restriction.
Most of the change happens naturally across six to twelve months as you settle into a routine that works. It is not a race, and it is not the first thing that matters.
If you are in Southampton and want support through pregnancy or the postnatal period, I work with women at every stage — including in-studio and mobile sessions that work around a baby's nap schedule. It is a specialised area and the plan should always be written around your medical team, not in spite of them.
Frequently asked questions
? Common questions about pregnancy and postnatal exercise
For most uncomplicated pregnancies, yes — moderate exercise is safe and recommended. You should still check with your midwife or doctor first, particularly in the first trimester, if you have any medical condition, or if your pregnancy is high risk.
Gentle walking is usually fine within days, once you feel able. For anything more structured, most women wait until their six-week postnatal check confirms recovery. Following a difficult birth, pelvic floor surgery or a caesarean, wait for your midwife or physiotherapist to clear you first.
Not while breastfeeding — restrictive dieting reduces milk supply. Postnatal weight loss should focus on gradual fat loss alongside strength and energy rebuilding, and it is not a race. Most of the change comes in the first six to twelve months, not immediately.
Diastasis recti is a common widening of the abdominal connective tissue after pregnancy. It is not a muscle tear and cannot be closed by crunches. Breathing, deep core work and appropriate loading help, but assessment by a women's health physiotherapist is the most reliable route.
