The truths and myths of working out while pregnant.

The truth about fitness and pregnancy from the eyes of a prenatal trainer

As a Prenatal and Postnatal Certified Personal Trainer, I have worked with a variety of clients in all different phases of motherhood.  I get a lot of questions about working out through your pregnancy, so I wanted to write this article to point out some common myths and also share some experiences from my clients that I have trained in the past.


 Sit Ups and Crunches during and after pregnancy should be avoided.

It’s true, sit ups and crunches may cause splitting of the abdominal wall, also known as Diastus Recti. This can be permanent if not treated.  Not only are sit ups and crunches one of the least effective core exercises in general, but they also put too much emphasis on the upper part of your core (rectus abdominis) which usually is the most overactive part of your abdominals.  Your growing fetus is already stretching the linea alba, which is the connective tissue that attaches the muscles at the midline of your stomach. Repetitive spinal flexion can cause irritation to that tissue, which is what causes the separation know as diastius recti.  You are better off doing isometric exercises that work the abdominal muscles while stabilizing the spine.  Strengthening these muscles can help reduce lower back pain during pregnancy.  Some examples of isometric core exercises are bridge, bird dog, plank, side plank, and Paloff Press.

You shouldn’t lay on your back for long periods of time while exercising during the 2nd and 3rd trimesters.

Once you are in the 2nd and 3rd trimesters, space in your uterus starts to become limited and lying flat on your back can actually put pressure on the vena cava artery restricting blood flow to your heart, which ultimately restricts blood flow to your baby.  The warning signs are clear because you will start feeling dizzy and nauseous in that position.  While short periods of time on your back may have no effect, and not every woman may experience discomfort in this position, if you plan on lying down, it’s best to workout elevated, using a wedge or bolster. 

Working out during pregnancy in hot conditions bad.

Heat is hard on the body whether or not you are pregnant.  While it’s healthy to sweat and get your heart rate elevated during your workouts, if your body temperature becomes higher than 102.2 degrees fahrenheit, you may be over heating.  This can cause headaches, heat stroke, dehydration, dizziness or heat exhaustion.  This is not healthy for you or your baby’s circulation.  As a pregnant woman, you are actually more likely to become overheated and dehydrated, than a regular person. Your baby is already warm enough surrounded in amniotic fluid, which is a slightly higher temperature than your body heat at roughly 99.7 degrees.  Saunas or jacuzzis are a definite no.  So it’s true, just to be safe, stay out of the heat while you are exercising.  Drink plenty of water, stay in shaded or air conditioned areas while working out and take plenty of cooling breaks.


You should keep your heart rate below 140 beats when you exercise.

When it comes to getting your heart rate up during pregnancy, it’s completely healthy and actually good for you and your baby.  According to the the Department of Health and Human Services, a minimum of 150 minutes of exercise spread throughout the week is recommended.  There are no specific heart rate guidelines to follow, however you can use the talk test. If you are working so hard that you can’t speak during your workout, this may be a sign that you are overdoing it, especially if you start overheating, getting a headache, flushing in your face or getting dizzy.  These symptoms are a sign that you should stop exercise immediately, because you do not want to put yourself in a position where you are decreasing blood flow to your fetus.  Know the warning signs and listen to your body. According to the Mayo Clinic, certain conditions like history of preterm labor, incompetent cervix, placenta previa, heart disease, high blood pressure or type 1 diabetes may cause higher risk of health problems during exercise, so always consult with your doctor and stop if you feel discomfort.  

Lifting weight is dangerous.

As long as you have proper technique and correct breathing, there is no harm in lifting weights while pregnant.  In fact, functional strength training exercises like squats and lunges are great to build strength in your core, hips and glutes.  This can prevent lower back pain and ease labor.  However, if you are not familiar with weightlifting and functional strength training, or you were not doing it before your pregnancy, you may want to look into hiring a prenatal trainer to help you with the proper techniques.  The last thing you want to do is hurt your back or strain a muscle while you are pregnant because of bad form.  The best and the most common repetition scheme that I use for my clients while weight lifting is 2-3 rounds of 12-20 reps of light to moderate weights.

 You shouldn’t exercise your abs while pregnant.

Yes, it is true you do not want to do spinal flexion exercises like sit ups and crunches during pregnancy because that may cause separation of the abdominal wall know as diastus recti.  You also do not want to do ab exercises on your back for long periods of time in the 2nd and 3rd trimester since that can compress the vena cava artery as the fetus grows (lying on an incline is recommended).  With my clients, I usually strengthen their core as much as I possibly can during the 1st and early 2nd trimesters.  I focus on isometric spine stabilizing exercises that strengthen the transverse abdominals, obliques and rectus abdominals.  These exercises include, planks, side planks, Paloff Presses, bridges, bird dogs and single leg lowerings.  During the 3rd trimester, I commonly hear that core exercises can become uncomfortable for some women as the belly gets bigger and there is more pressure on the core muscles.  With my experience, this varies from woman to woman.  I once had a client that I had doing planks until 3 days before she gave birth and she ended up having a very easy labor.  Other client’s I have had, prefer to skip certain core exercises because they feel it’s uncomfortable.  In that case, squats are a great core and pelvic exercise that puts less pressure directly on the core muscles.


Listen to your body, be familiar with the exercises or activities you choose to do and avoid activities that put you in an uncomfortable position or physically harm the fetus.  If you are unfamiliar with how you should exercise or what activities are safe, invest the money in taking prenatal fitness classes or hiring a prenatal trainer.  Learn how to move correctly and strengthen the proper muscle groups so that you may have the safest and healthiest pregnancy possible.  It’s your health and your baby, so it’s worth it!