Can I do Pilates while pregnant?

The verdict

Yes, and it is one of the few activities a major body recommends by name rather than merely tolerating.

ACOG lists modified yoga and modified Pilates among the safest exercises in pregnancy, alongside walking, swimming and water workouts, and stationary bicycling. Its description is specific: yoga reduces stress, improves flexibility and encourages stretching and focused breathing, there are prenatal yoga and Pilates classes designed for pregnant women, and these classes often teach modified poses that accommodate a pregnant woman's shifting balance.

It attaches one caveat in the same breath, and it is the caveat that runs through this whole page: you should avoid poses that require you to be still or lie on your back for long periods.

The NHS does not name Pilates specifically but its instruction covers it: keep up your normal daily physical activity or exercise for as long as you feel comfortable, and if you go to exercise classes, make sure your teacher is properly qualified and knows that you are pregnant, as well as how many weeks pregnant you are.

Why the supine rule matters more here than elsewhere

Mat Pilates is built on a supine foundation. The hundred, roll-ups, single and double leg stretch, and most of the classical order begin lying on your back, which is exactly the position the guidance asks you to limit.

The NHS explains why: do not lie flat on your back for long periods, particularly after 16 weeks, because the weight of your bump presses on the main blood vessel bringing blood back to your heart and this can make you feel faint. ACOG puts the threshold at 20 weeks and describes the mechanism as decreased venous return due to aortocaval compression from the growing uterus, leading to low blood pressure. It also advises avoiding standing motionless, because blood can pool in your legs and feet.

HSE Ireland words it as concerns about exercising in a lying down position after the first trimester, and gives the practical fix: as pregnancy progresses, avoid spending prolonged time lying down, and adapt exercises to a side-lying, standing or 45-degree incline position. It adds that you should avoid lying down altogether during exercise if it causes symptoms, and advises rolling to your side and sitting up if you get dizzy or lightheaded while on your back.

That is the single most useful adaptation on this page: 45 degrees, side-lying, all fours, or standing. A prenatal class will have made those substitutions already.

Reformer, mat and heated classes

No body distinguishes reformer Pilates from mat Pilates in pregnancy, so the same principles apply. The reformer does make some adaptations easier, because the carriage and the box allow inclined and side-lying work without improvisation.

Heated Pilates is the exception and here there is a clear position. ACOG names hot yoga and hot Pilates among the activities to avoid in pregnancy, on the basis that they may cause you to become overheated. HSE Ireland states that exposure to extreme temperatures during pregnancy can increase your risk of premature birth and certain birth defects, and names activities that lead to overheating.

So the answer splits neatly: Pilates is recommended, heated Pilates is on the avoid list.

The abdominal question

This is the one Pilates-specific worry and it deserves a straight answer about what is and is not known.

ACOG's Committee Opinion 804 notes that pregnancy weight gain and a shift in the point of gravity lead to increased forces across the joints and spine during weight-bearing exercise, that more than 60 per cent of pregnant women experience low back pain, and that strengthening abdominal and back muscles could minimise this risk. That is a positive statement about abdominal work rather than a warning against it.

What no body publishes is a position on specific abdominal exercises, on diastasis recti prevention, or on which movements to avoid as the abdominal wall stretches. Anyone giving you a definitive rule about crunches at 24 weeks is going beyond the evidence.

The NHS does publish specific stomach-strengthening exercises for pregnancy, and they are worth knowing because they are the closest thing to an official prescription: start on all fours with knees under hips and hands under shoulders, fingers facing forward and abdominals lifted to keep your back straight; pull in your stomach muscles and raise your back towards the ceiling, curling your trunk and letting your head relax gently forward without locking your elbows; hold for a few seconds and return slowly to the box position, taking care not to hollow your back. Ten repetitions, slowly and rhythmically.

Pelvic floor work is the point

If there is one reason to do Pilates in pregnancy rather than something else, this is it, and the NHS is emphatic about it.

It states that the pelvic floor comes under great strain in pregnancy and childbirth, that weak muscles cause leaking when you cough, sneeze or strain, and that all pregnant women should do pelvic floor exercises even if they are young and have no symptoms now. Its prescription is three sets of eight squeezes every day, done both quickly and slowly, holding as long as you can and counting to ten. It suggests doing a set at each meal so you remember, and practising tightening the muscles before and during coughing and sneezing.

HSE Ireland says the same in one line: all pregnant women should do pelvic floor exercises. A properly taught prenatal Pilates class builds this in.

Finding the right class

• Tell the instructor you are pregnant and how many weeks, which the NHS asks for explicitly.
• Ask whether the class is prenatal or a general class with modifications offered. Both can work; knowing which you are in matters.
• HSE Ireland advises contacting your GP, obstetrician or midwife if you want to start a new activity while pregnant or have a high-risk pregnancy.
• Expect to be given side-lying and inclined alternatives without asking. If you are not, the instructor is not adapting.

When to stop

HSE Ireland's list applies: contact your GP, midwife or obstetrician immediately if you have shortness of breath before or during exercise, chest pain or palpitations, feel faint or dizzy, have regular contractions, have severe abdominal, back or pubic pain, or notice reduced fetal movement. Short of that, the NHS says if any exercise feels uncomfortable, stop and get advice.

The short version

ACOG names modified Pilates among the safest things you can do. Get off your back after the first trimester and work at 45 degrees, side-lying or standing instead. Skip anything heated. Tell the instructor how many weeks you are. And do the pelvic floor work, which is the part of the class with the strongest recommendation behind it.