Is Exercise During Pregnancy Safe? Our Experts Share Exercise Benefits and Recommendations

Pregnancy is a testament to the strength of women, both emotionally and physically. For decades, women have been warned against exercise during pregnancy, specifically against raising their heart rates or lifting heavy objects out of fear of endangering either their lives or the lives of their babies.  

Research challenges these stigmas, showing that exercise during pregnancy is not only safe, but also encouraged to protect your health. Still, only 30% of pregnant women currently meet the recommended minimum activity guidelines. [1] 

Here, we break down the latest evidence-based guidance on exercise during pregnancy, featuring insights from experts in exercise science and women's health to help women embrace their strength throughout their pregnancy. 

What happens to the body during pregnancy? 

Pregnancy affects almost every system of a woman's body, as it goes from supporting one life to two. Here are the key hormonal and physical changes women experience during pregnancy. 

Hormonal changes: A woman's hormones change to support her baby's growth and prepare the body for birth. For example: [2, 3] 

During pregnancy, a woman's heart rate can increase by up to 20%, and blood volume increases by nearly 50%, to meet the new demands of a growing baby. Given these natural increases, it was once believed that further raising heart rate and blood volume through exercise could harm a baby's health.  

Dr. Brittany Leboeuf, MS, PhD, explains, "In 1985, the American College of Obstetrics and Gynecology created exercise guidelines for pregnancy. They recommended that pregnant women not get their heart rate above 140 beats per minute."  

Less than 10 years later, this recommendation was removed, as higher-intensity exercise during pregnancy was found to be safe and beneficial for both mom and baby. [7] 

"This recommendation was removed from the policies in 1994, yet some healthcare providers still give this advice to their pregnant patients," explains Dr. Leboeuf.  Research even shows that the increase in blood volume experienced during pregnancy can strengthen heart muscles, a benefit that continues postpartum. [5] 

What to do: Trust your body’s signals, rather than focusing on your heart rate during workouts. Focus on the intensity of your exercise by aiming for exercise that feels like a challenge yet allows you to speak in full sentences. It should feel like an intensity of 5-8 on a scale of 1-10, where 10 is your maximum effort.*  

*Ongoing research is investigating the safety of very high-intensity exercise during pregnancy, and these guidelines will likely be updated to reflect the results.  

Myth: Exercising during pregnancy can hurt the baby. 

In 2020, researchers in Poland found that 39% of mothers were told to stop exercising during pregnancy because it could increase the risk of miscarriage, preterm birth, and low birth weight. [5, 8] 

Many women significantly reduce their physical activity or avoid exercise during pregnancy altogether because of this fear. [8] 

The truth is that research does not support the claim that exercising during pregnancy is related to having a miscarriage. [5, 8, 9] 

It's important to note that almost 25% of women will experience a miscarriage. Women have been wrongfully blamed and shamed for contributing to their loss by exercising, without evidence that that's the case. Given how common this experience is, women’s mental and physical well-being should always be prioritized. [5] 

Beyond being safe, exercise during pregnancy offers health benefits for both mom and baby.

Regular activity may help reduce the risk of preterm birth, potentially through exercise’s ability to limit depressive symptoms in a mother. [10, 11, 12]  

While research shows that women who engage in vigorous exercise throughout pregnancy may give birth to babies that weigh slightly less (typically 200-400 grams or about half a pound), this does not mean they are not within the normal, healthy weight range. This small difference has not been linked to low birth weight (weighing less than 5 lbs 8 ounces) or impaired development. [10] 

Exercise, particularly strength training, can help prevent or reduce pain experienced during pregnancy. More than 60% of pregnant women experience low back pain, which can be alleviated by strengthening the abdomen and postural muscles. [14] 

What to do: Pregnant women should aim for 150 minutes of moderate-intensity exercise per week across at least 3 days, though daily movement is encouraged. Additionally, strength training of the hip adductors, pelvic floor, and abdominals can help with urinary incontinence and pelvic floor dysfunction. [13, 14, 15] 

Myth: Exercise during pregnancy can increase a mother’s risk of complications during birth.  

Beyond concerns about the baby's safety, many previously believed that exercise during pregnancy could increase maternal complications during pregnancy and birth. 

Research shows that the opposite is true — exercising during pregnancy is protective for moms.   

Studies show that multicomponent exercise programs (i.e., a combination of strength and aerobic training) reduce the risk of developing diabetes, hypertension, and preeclampsia during pregnancy. Staying active before giving birth can also increase chances of having a vaginal delivery and decrease postpartum recovery time. [14, 15, 16] 

Beyond physical health, exercise during pregnancy can also protect mental health. Prenatal depression impacts one in seven women. Participating in physical activity during pregnancy can reduce prenatal depression risk by 67% compared to inactive pregnancies. [5, 17] 

Inactivity during pregnancy may actually worsen a mother’s health. Dr. Leboeuf points out, “Telling a woman who finds a lot of enjoyment in participation in aerobic activity that it is unsafe could contribute to negative emotions or fear towards movement that is not evidence-based.”   

What to do: Focus on the activities that bring you joy and incorporate them into your daily routine. Centering your movement around activities you enjoy, whether that’s walking, yoga, or swimming, can help you to stay consistent, especially as you get further along in your pregnancy. Always work with a healthcare provider on modifications to stay active while minimizing risk.  

Myth: You shouldn’t start exercising during pregnancy if you weren’t active before.

Women who were previously inactive have often been discouraged from starting exercise during pregnancy. This stems from the misconception that pregnancy isn't the time to make lifestyle changes, especially if it can increase injury risk.

There is ample, strong research to the contrary.   

Women who began to exercise during pregnancy reduced the odds of developing gestational diabetes by 57% compared to those who remained inactive. The benefits of exercise discussed above stand true in women who were inactive before their pregnancy. [18]

What to do: If you’re new to exercise, start with lower intensity activities like yoga or walking, and gradually increase the intensity and duration of your workouts over time. Working your way up can help you stick with a routine and ensure that you’re approaching exercise safely. [19]