12 Pregnancy Exercise Mistakes That Can Harm You & Your Baby

The 12 most common pregnancy exercise mistakes include working out like you did pre-pregnancy, doing traditional crunches or planks, overheating, holding your breath, and ignoring coning. These errors can increase the risk of diastasis recti, pelvic floor damage, back pain, and reduced blood flow to the baby.

The good news: every mistake has a simple, safe alternative that keeps you strong and protects both you and your baby. At PregActive, you have comfort in knowing the workout you are doing is safe for you and baby.

Always consult your doctor or midwife before starting or continuing any exercise routine during pregnancy.

Why Do Pregnant Women Make These Exercise Mistakes?

Most pregnant women make these mistakes because they follow generic workout advice from non-specialist trainers or online videos. Pregnancy changes your body dramatically.

Hormones loosen ligaments, your center of gravity shifts, and your core and pelvic floor need different care.

Using pre-pregnancy routines or unsafe online content is the fastest way to create problems that can last into postpartum.

The 12 Biggest Pregnancy Exercise Mistakes (And How to Fix Them)

1. Working Out Like You Did Before Pregnancy

Continuing your old routine without modifications is one of the most common and risky mistakes. Your body changes when pregnant and so should your workouts.

Safe alternative: Reduce intensity, shorten sessions, and choose trimester-specific modifications. Focus on controlled, low-impact movement.

2. Skipping Pelvic Floor Exercises

Many women ignore their pelvic floor because the muscles are not visible.

Safe alternative: Include our PregActive "Hug and Wrap" technique in all your workouts and coordinated breathing. A strong pelvic floor reduces incontinence risk and supports recovery after birth.

3. Overheating (Hot Yoga, Saunas, Intense Cardio)

Raising core body temperature above 102°F (39°C), especially in the first trimester, is linked to neural tube defects and reduced placental blood flow. Avoid high temperatures!

Safe alternative: Keep intensity at a 'talk test' level, stay well hydrated, and avoid hot yoga, Bikram, or very intense cardio.

4. Doing Traditional Crunches or Sit-Ups

These movements increase intra-abdominal pressure and can worsen or cause diastasis recti. I avoided crunches when I was pregnant and I want you to do the same.

Safe alternative: Switch to deep-core activations, side-lying work, bird-dog, and transverse abdominis engagement.

5. Continuing to Plank

Full planks place high pressure on the linea alba and can increase abdominal separation.

Safe alternative: Use inclined planks, wall planks, or skip them entirely in favor of deep-core and side-body work.

6. Not Activating the Deep Core Properly

Many women 'suck in' or hold their breath instead of properly engaging the pelvic floor and transverse abdominis.

Safe alternative: Learn coordinated breathing + gentle core engagement first. Master the foundation before adding load or complexity.

7. Extreme Stretching or Deep Twists

Relaxin makes ligaments looser, so overstretching or closed twists can destabilize the pelvis and SI joints.

Safe alternative: Stretch only to mild tension, prefer open twists, and avoid deep forward folds after about 30 weeks.

8. Holding Your Breath (Valsalva Maneuver)

Holding your breath during effort spikes blood pressure and reduces oxygen delivery to you and baby.

Safe alternative: Exhale on effort (“blow before you go”), inhale on the release.

Make breathing the foundation of every movement.

9. Exercising on Your Back After the First Trimester

Lying flat on your back after 16-20 weeks can compress the vena cava and reduce blood flow.

Safe alternative: Perform floor work on your side, seated, inclined, or standing.

10. High-Impact or Contact Sports After the First Trimester

Jumping, running with impact, kickboxing, soccer, or any activity with fall risk becomes more dangerous as balance and joint stability change.

Safe alternative: Switch to walking, swimming, stationary cycling, or elliptical.

11. Lifting Too Heavy Without Proper Guidance

Heavy loads without adjusted form, breathing, or core bracing increase injury risk.

Safe alternative: Reduce load by 20–30% from pre-pregnancy maxes, prioritize perfect form, and stop immediately if you see coning.

12. Ignoring Coning or Doming of the Belly

A ridge or dome appearing down the midline during exercise signals poor pressure management and risk of worsening diastasis recti.

Safe alternative: Stop the exercise immediately. Exhale, gently engage the deep core, and choose a modified version that keeps the abdomen flat.

Dr.Scott Pearce

I recently spoke to Dr. Scott Pearce, Obstetrician and Gynaecologist about exercising safely with Placenta Previa. He said that; "The main concern is vaginal bleeding caused by disruption of the low-lying placental blood vessels. Activities that increase intra-abdominal pressure, involve impact, heavy lifting, or pelvic strain can raise this risk."

What Should You Do Instead?

Focus on pregnancy-safe principles:

1. Controlled breathing.

2. Deep core and pelvic floor activation.

3. Low-impact, trimester-appropriate movement.

4. Listening to your body and stopping at any warning signs (dizziness, bleeding, contractions, reduced fetal movement, chest pain). 

Frequently Asked Questions

Is it safe to exercise throughout pregnancy?
Yes, for most women with uncomplicated pregnancies. Always get clearance from your healthcare provider first.

When should I stop exercising during pregnancy?
Stop immediately if you experience dizziness, shortness of breath, chest pain, vaginal bleeding, contractions, or reduced fetal movement.

Can I still do strength training while pregnant?
Yes with reduced loads, perfect form, and proper breathing. Avoid any move that causes coning.

What is the safest type of exercise in pregnancy?
Walking, swimming, prenatal yoga/Pilates, stationary cycling, and guided trimester-specific programs are among the safest options.

Why Most Pregnant Women Make These Costly Workout Mistakes

All too often pregnant women are feeling unsure about how to exercise safely in their pregnancy to optimize their health and keep their growing baby safe.

The big mistake I see all the time is taking advice from trainers and YouTube influencers who have no forming training in prenatal exercise. And this leads to many mamas participating in online workouts that are unsafe for baby!

As a prenatal exercise expert with over 15 years of experience in helping pregnant women stay fit and healthy, I'm here to help you. It's my mission to help women stay fit and healthy during pregnancy.

Healthcare Provider

Always consult your doctor or midwife before starting or continuing an exercise routine during pregnancy.

Certain conditions may require you to avoid exercise or stick to specific low-impact activities.

Do not Over-exert Yourself

You will often hear me say that pregnancy isn't the time to push your limits. Avoid high-intensity workouts that leave you breathless or exhausted.

The goal is to maintain fitness, not set personal records.

Don't Ignore Your Body

Pregnancy changes how your body responds to exercise.

Stop immediately if you experience symptoms like:

1. dizziness

2. shortness of breath

3. chest pain

4. vaginal bleeding

5. contractions

6. reduced fetal movement.

These could indicate overexertion or a more serious issue requiring medical attention.

Maintain Correct Technique

As your belly grows, your center of gravity shifts, which can throw off your balance and form.

Avoid exercises that strain your lower back or abdominal muscles, like deep twists or heavy planks.

Look after Baby

However, there are common mistakes that many women make when exercising during pregnancy that can be harmful to both mom and baby.

We will cover important topics such as the risks of overexertion, improper form, and exercises to avoid during pregnancy.

Learn from Mistakes

By learning about these mistakes and how to avoid them, you can have a safe and effective workout routine throughout your pregnancy.

If you're expecting or know someone who is, be sure to watch this video to ensure a healthy and happy pregnancy journey.

Don't let these exercise mistakes derail your fitness goals during this special time.

Remember, always consult with your healthcare provider before starting any new exercise routine during pregnancy.

High-Impact Exercises

High-impact exercises can pose significant risks during pregnancy, primarily because they involve movements that are jarring to the body and may lead to increased pressure on the pelvic floor.

Do you know that certain activities like running, jumping, or any exercise that involves sudden starts and stops can lead to discomfort and potential injury?

The added weight and shift in the center of gravity during pregnancy can also affect balance and coordination, increasing the risk of falls, which can be detrimental to both mother and fetus.

Body Changes when Pregnant

It's important to recognize that the body undergoes many changes during pregnancy, including increased joint laxity due to hormonal shifts which can make joints more vulnerable to injury.

Therefore, it's critical to adjust exercise routines to accommodate these changes and avoid high-impact exercises that may exacerbate these risks.

Be Empowered

We want you feeling empowered, informed and confident in your exercise choices, because you deserve it!

It is worthwhile learning about pregnancy hormones like relaxin. This hormone help prepare the body for childbirth by loosening ligaments and joints, possibly leading to an increased range of motion.

There is a negative side to this however in that this natural loosening can also make it easier to overstretch and potentially cause injury.

It's essential to be cautious with activities that involve deep stretches or extreme ranges of motion, such as advanced yoga poses or gymnastics.

Overstretching can lead to:

1. strains
2. sprains
3. joint dislocation

Make sure you pay close attention to your body's signals during exercise and avoid pushing yourself into uncomfortable positions.

Gentle stretching when pregnant within a comfortable range is beneficial, but it's crucial to avoid the temptation to stretch further than usual just because the body seems more capable of it during pregnancy.

Contact Sports

Contact sports such as soccer, basketball, hockey, and boxing should be avoided during pregnancy due to the high risk of abdominal trauma.

These sports often involve unpredictable physical contact that can lead to injury, not just from the sport itself but also from accidental impacts from other players.

Avoid Direct Contact

The biggest concern I have with contact sports is the potential for a direct blow to the abdomen, which can be dangerous for the developing baby.

Additionally, as pregnancy progresses, the body's center of gravity shifts, which can affect balance and make falls more likely.

This shift, combined with the natural joint loosening that occurs during pregnancy, can make even non-contact elements of these sports riskier.

Fitness and Safety

So, I want you to avoid the exercises I have listed above. But there are many other exercises that can be safely modified to accommodate the changing body with each trimester.

Example

Instead of high-impact jumping or running, pregnant women can switch to low-impact activities like walking when pregnant or using an elliptical machine.

Strength training can continue with modifications, such as avoiding heavy weights or exercises that involve lying flat on the back after the first trimester.

Listen to Your Body

Exercises that require balance, such as certain standing yoga poses, can be modified by using support like a chair or wall to prevent falls.

It's crucial to listen to the body and make adjustments as necessary, prioritizing stability and comfort over intensity or performance.

Ready for Safe Pregnancy Workouts?

Avoid these mistakes by following expert-designed programs created specifically for pregnancy:

1. PregActive Pregnancy Programs – trimester-specific, medically recommended workouts

2. 1st Trimester Program

3. 2nd Trimester Program

4. 3rd Trimester Program

5. Birth Prep Program

After birth, continue safely with the Core Rehab Program and full Postpartum Workouts.

Reference

ACOG Physical Activity and Exercise During Pregnancy and the Postpartum Period

The PregActive Method

Related Articles

Can You Do Crunches or Sit-Ups While Pregnant? Safety by Trimester

Can I Do Planks While Pregnant? Safety, Risks & Safer Alternatives

For safe workouts check out my PregActive YouTube channel >

Article review: Article updated and reviewed by Kerryn Boyle on 23/09/2026.