Figuring out what is safe or not safe for prenatal workouts can be overwhelming! There is a lot of conflicting information out there about prenatal fitness, with one source saying this is the most dangerous thing you can do, but other sources state something completely different. So many of the myths about prenatal fitness are not true and are mostly based on fear and misconceptions about the safety of exercising throughout pregnancy.
Unfortunately, these myths have greatly impacted the number of us who feel confident to exercise throughout our pregnancies. Thus, the number of us meeting the minimum recommendation of 150 minutes of moderate-intensity exercise per week is very low!
In this blog, we will be breaking down the common myths about prenatal workouts, and debunking them so you can feel confident with approaching fitness throughout your entire pregnancy!
Common Myths About Prenatal Workouts
These are not even ALL of the myths out there about prenatal fitness, but these are the top ones that we see discouraging many of you from even attempting exercise–after all, if you’re being told that exercising can harm your baby, why would you even risk it??
The good news, is all of these myths are mostly false (and of course, are more complex than a simple yes or no) which we will break down in this blog post.
There are so many myths about the safety of working out throughout your pregnancy. Some of these myths are more prevalent in older generations, and some are even promoted as true by our medical providers or other professionals supporting your pregnancy. So, it is understandable that it can be really confusing to know what is fact and what is fiction!
Here are the top myths that we see being pushed as fact toward prenatal athletes:
- Exercise increases the risk of miscarriage, especially lifting weights.
- Exercise can cause preterm labor.
- You should always keep your heart rate below 140 beats per minute.
- You should always be very cautious about overheating during exercise.
- You should never twist your torso.
- You should never do ab exercises.
- You should never exercise on your back.
If you are feeling overwhelmed by what to even do during your pregnancy–you know it’s beneficial, but not sure HOW to even workout safely–join our prenatal workout programs! We offer our programs in two main formats:
- Teambuildr App: List of exercises with short demo videos. You work out at your own pace. This program is offered in full-length workouts and mini-length workouts!
- On-Demand Videos: Full-length workout videos that you follow as you workout at the same time
Feel strong and move comfortably throughout your entire pregnancy. Our program syncs to your current week of pregnancy, so you can start at any time!
- 5 Workouts Per Week
- Labor Prep Workouts
- Teambuildr App Access
Now, let’s break down these prenatal fitness myths so you can know what’s fact and what is fiction!
1) FALSE: Exercise increases your risk of miscarriage.
Exercise does NOT increase the risk of miscarriage. This is a common belief and may discourage you from exercising in the first trimester due to fear of losing your pregnancy. It is important to understand that the majority of miscarriage is due to chromosomal abnormalities. This means that there is nothing you could have done to cause that miscarriage, and sadly, nothing you could have done to prevent it.
Research strongly supports that there is NO increased risk of miscarriage with exercising in the first trimester–even with vigorous, high-intensity exercise or heavy lifting. But this is a common belief nevertheless, mostly due to an outdated notion that pregnancy is a fragile time, and we should refrain from strenuous movement. Because of this belief, less than 15% of us during pregnancy meet the minimum guidance on prenatal fitness throughout our pregnancies!
The worst part about this myth is that if you do have a pregnancy loss and you were exercising, it may increase the burden of your loss. You may feel responsible for your miscarriage, and instead of feeling supported by your community, you may be blamed for this loss when it was not your fault.
References:
- Why can’t I exercise during pregnancy? Time to revisit medical ‘absolute’and ‘relative’contraindications: Systematic review of evidence of harm and a call to action
- Prenatal exercise is not associated with fetal mortality: a systematic review and meta-analysis
- The Influence of Physical Activity during Pregnancy on Miscarriage—Systematic Review and Meta-Analysis
2) FALSE: Exercise causes preterm labor.
Another common myth is that exercising can cause pre-term labor. This myth is false but probably is around due to the prescription of bed rest to prolong a pregnancy that has developed a complication that may cause you to go into labor earlier. Bedrest is outdated, and research supports that it does not prolong pregnancies that have an increased risk of preterm birth. Plus, bedrest may actually worsen your birth outcomes.
Bed rest is when you are restricted to the bed for the majority of your day. You can get up to use the restroom, but primarily you are off your feet and stationery. Immobility could increase the risk of blood clots and other complications, such as affecting your bone health. This limitation can also cause muscular atrophy, where your muscles get smaller and weaker in response to lack of movement and use.
This weakening of muscles can increase discomfort throughout pregnancy, as many prenatal discomforts can be solved with strength training. This weakening can also affect labor, as we need stamina to maintain an upright position and move frequently throughout our labor to support our baby’s position and descent through the pelvis. Lack of stamina from inactivity for potentially weeks during the last part of our pregnancy can make it harder for us to move and support our labor progress.
And then into the postpartum period, it may affect our healing timeline. After birth, we want to limit our overall movement as our tissues begin the initial healing timeline–during this healing period, we will likely experience some muscular atrophy and deconditioning as we rest for 2-4 weeks. In this deconditioning period, if we start at a higher level of fitness, it will be easier to resume a rehabilitation program to initiate our postpartum return to fitness. If we already started our postpartum in a deconditioned state, it could prolong the healing timeline.
Obviously, we want to prolong pregnancies that are at risk of giving birth before a baby is at term (37 weeks or later). However, research does not support that bed rest prolongs pregnancies. So, weighing the potential risks of bed rest on your pregnancy, birth, and postpartum recovery knowing that bed rest is not supported by research to prolong pregnancy, is important in deciding if bed rest is appropriate for you. Even ACOG, the governing body of OB-GYNs states that bedrest is not recommended for most women and that there is no scientific evidence to support that bed rest prevents preterm labor or reduces preeclampsia risk. If your provider is recommending bed rest, ask if there is ANY activity that you can do to prevent the complications of bed rest, such as in-bed mobility and strengthening exercises.
References:
- ACOG Guidance on Bed Rest
- ACOG Guidance on Activity Restriction
- Activity Restriction and Hospitalization in Pregnancy: Can Bed-Rest Exercise Prevent Deconditioning? A Narrative Review
- Why can’t I exercise during pregnancy? Time to revisit medical ‘absolute’and ‘relative’contraindications: Systematic review of evidence of harm and a call to action
3) FALSE: You should always keep your heartrate below 140 bpm.
It would be really convenient to have an easy-to-define metric to know if you are working out too easily or too hard during your pregnancy. Unfortunately, heart rate is not a great tool because there are SO many variables that can affect your heart rate, including your week of pregnancy.
Variables that affect your heart rate can include your fatigue levels, hydration status, age, fitness level, and even your week of pregnancy or trimester–earlier in pregnancy, your heart rate may be more elevated with easy efforts while later in pregnancy even vigorous efforts may not raise your heart rate at all. So you can see how using your heart rate as a tool is not helpful!
Maintaining a heart rate below a specific target does not mean that your workout is “safe,” nor does going above a specific target mean your workout is now “unsafe.” Exercising in a wide range of intensity levels is generally safe throughout pregnancy–to include vigorous exercise.
But it can be helpful to know what level of intensity you are working out at so you know that you are meeting the minimum moderate intensity recommendations!
Some helpful ways to know how hard you are working out can include the talk test for aerobic activity and weight percentages for strength training.
Talk Test: The talk test is a method to gauge your effort levels while exercising, more so with cardio or aerobic activities like running, walking, or stationary cardio machines. When you are exercising, you can try to speak and see when you need to pause talking to take a break to catch your breath. The longer you can talk without needing a break, the lower the intensity of your workout. Ideally, we are working out primarily in the moderate-intensity range!
- Low Intensity: Able to speak easily without needing to take a break from talking
- Moderate Intensity: Able to speak about a sentence before needing to pause to take a break from talking
- High Intensity: Only able to speak a few words before feeling winded or needing to take a break from talking
Weight Percentages: If you are doing resistance training, using percentages of your 1RM can be helpful to gauge your effort levels. I also find that looking at how easily you can complete all reps in your set as a helpful gauge!
- Low Intensity: 50-60%; able to easily do all repetitions without any struggle or need to bail. Your form is near perfect with every single repetition. After completing your set, you feel you could do at least 5 more reps.
- Moderate Intensity: 70-80%; able to do all repetitions without needing to bail the weight, but last few repetitions are more challenging. After completing the set, you feel you could do maybe 2-3 more reps. This is our target range for lifting!
- High Intensity: 80-100%; difficult to do all the repetitions without needing to bail the weight but may require a spot in order to help with the last repetition or two. After completing the set, you should not feel like you could do another repetition without failing.
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If you want more guidance on how to approach your workouts throughout your pregnancy, join our prenatal workout programs! Our workout programs guide you week-by-week throughout your pregnancy, with modifications based on our experience working with hundreds of in-person prenatal fitness clients. Explore our programs here!
4) MAYBE: You should always be very cautious about overheating during exercise.
The risk of overheating is a big concern throughout pregnancy–overheating or raising your core body temperature could affect your baby! BUT the good news is our pregnant body is MUCH more efficient and keeping ourselves COOL and regulating our body temperature. This vital function makes a ton of physiologic sense–after all, why would we want to be able to easily increase our core body temperature if we know that would harm our baby?? So, as a result, our body is much better at keeping ourselves cool throughout pregnancy. During the first trimester, we are about 30% more efficient at keeping ourselves cool, and by the third trimester, our ability to keep ourselves cool increases by as much as 70%!
However, even with this improved skill of maintaining your core body temperature, even with vigorous exercise, we do want to still be mindful of our environment when exercising and maintaining hydration during workouts. If a normal person would not exercise in that environment, you probably shouldn’t during pregnancy. For example, a normal person would not exercise inside a sauna–I would also not recommend that during pregnancy. A normal person would not go for a run at noon in the middle of the summer in Florida–you probably shouldn’t either during pregnancy.
A systematic review found that exercising for up to 35 minutes at 80-90% of your maximum heart rate at 25 degrees Celsius or 77 degrees Fahrenheit at 45% relative humidity did not cause the core temperature to exceed levels that could be harmful to your pregnancy.
So, the fear-based recommendation to be super cautious about overheating during prenatal workouts is not entirely true. Yes, we absolutely want to be aware of our environment and hydration while working out. But, we don’t need to be overly fearful or cautious! We are really good at keeping ourselves cool during pregnancy!
5) FALSE: You should never twist your torso.
This myth is more prevalent in the yoga community. And this myth is false. You should absolutely be twisting throughout your pregnancy, and the lack of twisting may cause more issues for you.
Why is this a common misconception? The thought is that twisting can compress the uterus and cause harm to the baby, or that twisting in the abdomen can cause issues or complications for your placenta. Fortunately, there is a LOT of protection around your baby between the various layers of tissues and muscles and then the actual uterus itself has protective features for your baby and placenta. So, twisting your torso will likely NOT cause any harm.
I would recommend avoiding deep abdominal compression-type twists mostly due to comfort–these types of twists are sometimes known as “detoxing” twists in the yoga world and would just not be very comfortable on a pregnant belly.
But why would NOT twisting cause issues for you?? Our spine NEEDS to twist and rotate in order to function properly. Our thoracic spine (upper back) and hips are meant to be VERY mobile. When we limit rotation or twisting, it can increase discomfort or pain in the upper, mid, or even lower back and potentially contribute to pelvic pain.
This lack of rotation in the pelvis typically results in an emphasis on external rotation at the hip (open hip positions with the toes pointed out) that can tighten the posterior portion of the pelvic floor. This muscular imbalance in the pelvic floor could contribute to things like tailbone pain, constipation, and even pelvic girdle pain!
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Prenatal fitness is more than just preparing for birth! We also want to be comfortable and enjoy our prenatal experience too! Join this course to gather the tools to do just that!
- Common causes of pelvic girdle pain
- Pelvic reset exercises for immediate relief
- Pelvic stability strengthening exercises for long-term pain relief
A counter to the recommendation to never twist is to only do OPEN hip positions when you are practicing yoga or incorporating rotation. Open hip positions are when the belly rotates OUT or points away from the legs. This is usually an external rotation at the hip, where the toes point outward. While external rotation is a part of the hips’ range of motion, and we do want to incorporate it, it is also a predominate movement pattern during pregnancy. If we only emphasize external rotation in our workouts, we will likely have some issues.
If we can only really find external rotation at our hip, or open hip positions, it can limit our ability to find internal rotation at the hips and closed hip positions that are vital to opening the lower half of the pelvis (supports your birth) and important as a part of stabilizing the pelvic girdle (supports your prenatal comfort).
Closed hip positions, or internal rotation at the hip, is when the belly moves toward the thigh or leg. This is commonly thought to be dangerous for pregnancy! But this is not true–mild belly compression against your thigh is not an issue. But avoiding all closed hip positions can become an issue!
We need internal rotation at the hip in order to open the lower half of the pelvis–this is really important for birth! If you CANNOT open the lower half of the pelvis with internal rotation, your baby will have more difficulty finishing their rotation out of the pelvis. This may result in a late labor stall.
Additionally, internal rotation at the hip is how we stabilize the pelvis when weight-bearing (such as walking). Internal rotation at the hip helps the pelvic joints better align so that they can form close (compress on themselves to stabilize).
So, yes, it is so important to be able to twist throughout your pregnancy and the recommendation to NOT twist can cause more issues for not only your prenatal comfort but also your birth!
6) MAYBE: You should never do ab exercises.
First, we need to understand what a core exercise is–it is more than sit-ups and crunches, and other “traditional” ab exercises. We need to view the core as more than just our six-pack abs. Our core is our entire torso–it helps to stabilize our spine and is where we anchor ourselves in order to move.
When I move my arms and legs, I want my torso to maintain its position (stabilize). Or I want my torso to change its position to stabilize with more dynamic movement, such as rotation with walking.
Why would you want to avoid ab exercises? If an abdominal-focused exercise is causing abdominal coning, where the center of the abdomen pushes out further than the rest of the abdominal wall, then we would want to modify or avoid that exercise.
So, what can you do then if we are avoiding core exercises that cause coning?? A lot!
- We can focus on anti- core exercises or movements that resist movement of the torso, such as the pallof press or bird dog.
- We can focus on rotational exercises (see above how twisting is perfectly find throughout pregnancy), such as the diagonal banded pull-down or upward chop.
- We can focus on hip extension while maintaining our torso position, such as one-sided squats or lunges.
Maintaining your core strength throughout pregnancy is important! It helps you stay comfortable throughout your pregnancy, as it improves your stabilization. It can support your baby’s position (too loose of an abdominal wall can affect your baby’s position). And, it can support labor by helping you push!
But we want to make sure that the core exercises we are doing are not causing coning. If you are experiencing coning, we want to modify or change the exercise so that we do not experience coning.
7) MAYBE: You should never exercise on your back.
This is also a maybe! Generally, you can exercise on your back, or in supine positions, without any issues during pregnancy BUT research is not strong in either direction. The concern is that supine positions can increase pressure on the inferior vena cava and aorta, which could decrease blood flow to the baby. However, usually, this is not an issue until the latter half of pregnancy, so exercising in the first half of your pregnancy in a supine position is generally fine. You may be able to continue supine exercises into the latter half of pregnancy, depending on your symptoms!
How do you know if supine exercises are not optimal for you anymore? If you have any symptoms of light-headedness, nausea, feeling unwell, or dizziness, then you may want to avoid supine positions. We can modify to inclined or upright positions, instead! For example, instead of a supine barbell bench press, we can modify it to an incline dumbbell bench press or a standing banded/cable chest press exercise.
Stay confident as you workout throughout your pregnancy!
All of the conflicting guidance out there about what is safe or not safe for prenatal workouts can be confusing! Much of the guidance is based on fear–avoid these exercises or else! This fear-based or avoidance-based approach does not really give you any guidance on what you can do for workouts, and may discourage you from exercising at all.
There is really not much that is truly “unsafe” for workouts throughout your pregnancy–low to high levels of intensity are generally fine; you can twist and rotate; you can even do supine exercises on your back! But, the key for prenatal workouts is to really pay attention to the messages from your body! Adjusting our workouts based on what we are feeling each day with our workouts is so important and the key to keeping your workouts optimal for you and for your baby!
If you want to learn more about HOW to approach prenatal workouts, join our prenatal fitness programs! All of our workout programs come with an educational course that teaches you HOW to safely exercise throughout your entire pregnancy plus tons of modifications based on common issues we see with our in-person prenatal fitness clients. Explore our programs here!