Myth Busters: Exercise in Pregnancy (Part 1)

I hear and see a lot of fear around exercise during pregnancy – mostly stemming from older “myths”, passed on from parents or grandparents generations. Lucky for us – we live in an age of information. And although there are still many leaps and bounds to be made into women’s health research, there is some information on this and it might be the opposite of what you’ve heard.

Disclaimer: this blog is for informational purposes only. Not medical advice. Please direct any medical questions to your health care provider.

Myth: Exercise in early pregnancy increases the risk for miscarriage.

False.

At this time – no evidence exists that suggests exercise at any point in pregnancy increases a person’s risk of miscarriage.

Miscarriage occurs in roughly 10-15% of recognized pregnancies (meaning you know you are pregnant – the number may be higher when accounting for unrecognized pregnancies). Keep in mind that this percentage also depends on other factors and may be different depending on things like maternal age or partner’s age, etc. Miscarriage most often occurs in the first trimester – but no current evidence relates it to exercise.

Exercise is actually recommended in low risk pregnancies. The American College of Obstetricians and Gynecologists and the Society of Obstetricians and Gynaecologists in Canada recommend 150 mins/week of moderate activity (they advise at least 3 days per week but some activity daily is ideal).

Moderate intensity means exercise that increases your heart rate – but you should still be able to speak while doing it. A brisk walk is an example of moderate intensity activity.

But the verdict at this time is no, it is not related to an increased risk of miscarriage. Your miscarriage risk would remain the same – and it goes down every day of your pregnancy. If you’re looking for reassurance, I love this website.

One thing I will say is if you have any concerns re: contraindications to exercising in pregnancy, please talk to your maternal care provider.

Myth: I shouldn’t start exercising during pregnancy if I didn’t exercise before.

Not exactly the truth. There are some groups of pregnant women who should avoid exercise – or at least address the issue with their providers & follow their guidance. But it’s not people who didn’t regularly exercise before.

If you weren’t exercising before pregnancy, it doesn’t mean you cannot exercise during pregnancy. You can start to exercise – but should do so under the guidance of your healthcare provider and gradually increase duration and intensity. That means – don’t try to start off doing HIIT or Olympic level weightlifting. Start with a low impact class or low intensity aerobics class. Even walking is physical activity and exercise that is often undervalued. So, even just starting there may be a good option. Speak to your healthcare provider for guidance if you are in this situation.

If you weren’t exercising before because of a health condition – also speak to your provider. Exercise is not necessarily recommended for pregnant people with certain conditions. Additionally, certain conditions of pregnancy (such as pre-eclampsia, IUGR, incompetent cervix – full list available here) may be contraindications for exercise. Again – best to review the guidance & recommendations with your provider and see what you are and are not able to do safely.

Myth: I shouldn’t lift my arms over my head in pregnancy.

A definite false. Just lifting your arms over your head will not hurt your baby. We would be in big trouble if that was the case.

This one drives me nuts! I actually had people tell me this during my first pregnancy too!! That I should be careful doing shoulder presses because it might cause my baby to strangle themselves with their umbilical cord…

First of all – there is no science behind this claim. Your arms are not in some way connected to your womb & the umbilical cord.

Second – the true recommendation this probably refers to is likely in reference to the potential risk of lifting heavy objects over your head, especially later in pregnancy. It’s just like we want to just generally be more careful as the bump grows you know? A trip or a fall, or a heavy object coming crashing down on the belly – that can be problematic. But if you’re lifting weights or something and you know you can safely lift them… especially in first trimester, this will not cause your baby harm.

The Center for Disease Control actually has a document for guidance if you lift at your job.

The CDC also mentions something important in their guidance on lifting in pregnancy – this is a difficult subject to study. No one can give you a “safe” amount to lift as a recommendation, because this simply has not been explored or studied. It would be unethical to test the strength and safety limits of pregnant women lifting things – and I’m sure you understand why. So the guidance they provide here is just that – guidance. Obviously weight limits may be different depending on the person and what they were doing prior to pregnancy, but it could also depend on so many other factors. Honest moment: we just don’t know. So it’s important to review any strenuous physical activities with your provider – especially if you’re doing things like this daily in the workplace. And be careful – and safe.

I think this is also a good time to mention that even if you do lift weights regularly, you might want to or have to drop down a little bit during pregnancy as especially as the weeks go on. For safety, caution, and probably because you’re also feeling physical discomfort already just from growing a baby. You’re likely going to become slightly imbalanced as baby grows and this puts you at risk of injury. Talk to your doctor if you regularly lift weights prior to pregnancy and have concerns about what is safe. If you’re looking for good workouts with weighted and bodyweight options – I love 1Hera! And Brittany just completed her prenatal program herself too, so she has great instructional videos for mamas as the bump grows!

Myth: I need to keep my heart rate under 140 BPM.

Depending on who you are, during exercise this may be very difficult! And it’s also not true – unless it has been recommended by your care provider.

For a low-risk pregnancy, you can exercise and not worry too much about this. The only time you should really be concerned is if your provider has advised you to monitor this or your activity level – and it isn’t specifically “140 bpm” but whatever guidance your provider has given you. This heart rate recommendation is based on an aged recommendation from the ACOG. Newer recommendations from the ACOG suggest looking instead at how much you are exerting yourself vs your heart rate during exercise.

A review & meta-analysis done in 2019 actually found that even vigorous activity in the third trimester of pregnancy is safe for most low-risk pregnancies. Not as much data exists on first and second trimester. And you should still talk to your provider if you’re about to do anything unusual. Oh, and remember safety! Like I said above – we aren’t as balanced and nimble as usual, especially not in third trimester!

I thought this was going to be a quick post – but there will be a part 2! Stay tuned for more info on pregnancy & exercise. As always, please let me know if any information is out of date or needs correction, info@elephantinthewomb.ca.