Weight Lifting During Pregnancy: Everything You Need to Know

Here at Dioxyme, we get asked quite regularly “Is weight lifting during pregnancy safe?” and the short answer is yes. Numerous studies have addressed this very question and the findings overwhelmingly suggest that lifting weights during pregnancy can actually be beneficial for both mother and child alike.

However, there are certainly some things that you’ll need to be aware of in order to make sure that you're training safely and effectively during your pregnancy.

That's why in this article, we’ll be going over the importance of things like training experience and exercise selection as they relate to you and your baby’s safety. We'll also be covering some of the benefits you can expect to see from lifting weights while you're pregnant, but before we get into any of that, let's first dispel some popular myths.

Is Weight Lifting During Pregnancy Safe? [Myths Debunked]

There are all kinds of misconceptions out there that discourage women from weight training during pregnancy.  From increasing the risk of miscarriage to upping your baby’s chance of being born underweight, there are plenty of claims about why you shouldn’t be lifting weights while you’ve got a baby on the way.

However, the truth is that many of these commonly held beliefs are not based on medical facts.  In reality, a number of them have actually been thoroughly repudiated in prospective scientific studies.

The overwhelming consensus amongst experts is that regular moderate exercise can be perfectly safe and healthy for women during pregnancy.

Myth #1: Musculoskeletal Related Injuries

One of the most common myths you’re likely to come across is that weight lifting increases your risk of musculoskeletal injury during pregnancy.  The origin of this one seems to lie in the fact that during pregnancy there is an increased concentration of the hormone relaxin.

Relaxin does help make the joints looser however, people extrapolated this fact to mean that exercising with higher relaxin levels increases the risk of injury.  In reality, there just isn't any science to back this claim up.

In fact, numerous studies have found the exact opposite: when the appropriate training guidelines were followed, resistance training actually helped to reduce the amount of self-reported pain and discomfort in those who trained regularly during pregnancy. ^(1)(2)(3)

Research suggests that lifting weights helps to strengthen your connective tissue and increase your lumbar endurance, reducing the risk of injury to your muscles, tendons, bones, and joints.          

Myth #2: Baby Size and Health    

Another popular myth is that weight training later in pregnancy can decrease birth weight and negatively impact your baby’s health.  This concern too is unsubstantiated by any science.

Researchers have specifically evaluated the effects of light to moderate resistance training during the 2nd and 3rd trimesters.  They found that when proper training procedures were followed, prenatal weight lifting had no negative effects on the newborn’s size or overall health. ⁽⁴⁾⁽⁵⁾

Myth #3: Risk of miscarriage

There does appear to be some evidence that strenuous lifting during the very early stages of pregnancy may increase the likelihood of miscarriage but only during implantation, which typically occurs somewhere between 6 -12 days after ovulation.⁽⁶⁾

With that being said, there is no scientific evidence to suggest that exercise in any way increases your odds of having a miscarriage at any other time during pregnancy. ^{(7)(8)(9)(10)} In fact, one systematic review of the relationship between exercise and fetal death concluded “[the findings] suggest that generally speaking exercise is ‘safe’ with respect to miscarriage and perinatal mortality.”⁽¹¹⁾

Myth #4: Body Temperature and Fetal Development

There is a commonly held belief that an elevated temperature caused by exercise can lead to developmental issues in a fetus.  This may stem from rat studies, where researchers found that when rats were exercised in hot environments, there was an increased risk to fetal nervous system development. ⁽¹²⁾ Studies in humans, however, show no such risks to fetal development.

Most research suggests that during pregnancy, your core body temperature shouldn’t rise above 38.9°C.  Findings show that the risk of developmental defects increases for the fetus when the mother's temperature goes beyond this point.  However, studies show that moderate exercise (up to 70% max heart rate) does not increase your body’s core temperature at all. ^(13)(14)

Benefits of Weight Lifting During Pregnancy

Not only can lifting weights be safe during your pregnancy, but it can actually be beneficial.  In fact, there have been numerous studies illustrating the potential benefits prenatal resistance training can have for both you and your baby.

1. Support Healthy Fetal Development

Mothers who participated in resistance exercise 3-5 times per week, on average, had babies that were both longer and leaner -- a high percentage of lean mass is very healthy for your baby. ⁽¹⁵⁾

In addition, those born to mothers who developed gestational diabetes had a lower incidence of macrosomia. ⁽¹⁶⁾ On top of that, moms that lifted weights during pregnancy also, on average, had children who showed greater neurocognitive development during childhood.⁽¹⁷⁾

2.  Reduced Incidence of Gestational Diabetes

Mothers who develop gestational diabetes during pregnancy are also at an increased risk of having diabetes later in life. In addition, their offspring have an increased likelihood of developing obesity and diabetes as well.

However, performing resistance exercises during pregnancy has been shown to decrease the risk of gestational diabetes by as much as 60%. ⁽¹⁸⁾  In addition, for those who do develop it, their need for insulin is significantly reduced. ⁽¹⁹⁾

3.  Reduced Incidence of Preeclampsia

Preeclampsia is the development of elevated blood pressure, swelling (edema) in the legs, and protein spilling into the urine.  It is the #2 leading cause of maternal death in the U.S.

Several studies have shown that exercise decreases the risk of preeclampsia and perhaps may also help to lessen its severity.  In addition, the intensity of exercise has a direct correlation with the risk -- the more vigorous the exercise, the lower the risk in general.

4.  Decreased Lower Back Pain

Three out of four women will experience significant lower back pain during pregnancy.  This is due to a variety of factors, including an expanding abdomen and changing center of gravity, as well as changes in the ligaments of the spine.

During pregnancy, many women can become incapacitated by their pain.  However, core-focused resistance exercises have been shown to significantly relieve lower back pain.

Your core is responsible for keeping your torso (including your belly) stabilized and supported. However, as your belly expands, your lower back often becomes overworked.  

For many women, lower back pain stems from the fact that their core muscles just aren't strong enough to manage the additional stress.  But training your core strengthens those muscles, helping your body to handle the extra demands that pregnancy can place on your lower back.     

5. Make The Labor Process Easier

Labor is a physically intensive process that can ultimately last for hours on end.  However, studies show that women who exercise are significantly more likely to have shorter labors in comparison to sedentary individuals.⁽²⁰⁾

Research also shows that women who weight trained during pregnancy, on average, required fewer interventions like C-sections and inductions during delivery.  

This may be due to the fact that weight training (and other forms of exercise) help to increase the ability of your placenta to transport oxygen and nutrients to your baby. ⁽²¹⁾ Ultimately, a fetus with more oxygen and nutrients may be able to better handle stressors during the labor process, reducing the need for intervention.

6.  Maintain Strength and Lean Body Mass.

During pregnancy, women may be at an increased risk of losing muscle.  However, in combination with an adequate supply of protein and supplements like BCAAs (which also support healthy fetal development), resistance exercise can help prevent this.   

The loss of lean muscle mass can ultimately increase your risk of musculoskeletal injury both during and after pregnancy.  However, lifting weights while you’re pregnant can help you to maintain your strength and preserve your lean body mass.  

7. Enhanced Weight Management

In the first trimester, your body will retain more water and your blood volume will also go up.  In combination with an increased metabolic rate requiring around 300 extra calories a day, this will lead to 8-10 pounds of weight gain for most women during their first trimester. ⁽²²⁾ As your weight and caloric intake go up, the risk of gaining excess body fat also increases.

However, weight training can be an effective means of combating excess fat gain while you’re pregnant.  For instance, one study found that women who regularly exercised during pregnancy on average gained about 20% less weight compared to sedentary individuals.⁽²³⁾

Lifting weights helps to increases the amount of fat oxidation that occurs in your muscles.  Fat oxidation is the process where your muscles use free fatty acids to generate energy. So, not only does lifting weight help to preserve your muscles, but it also helps encourage your body to burn excess body fat.  

8. Improved Mental Health

Pregnancy causes dramatic hormonal changes to happen in your body, which amongst other things, can affect your mood.  In fact, the risk of developing depression doubles with pregnancy. ⁽²⁴⁾

Physical activity during pregnancy has been directly correlated with maternal mood and risk of depression. Women who routinely perform moderate amounts of exercise, on average, have lower risks of anxiety and are less likely to experience symptoms of depression during pregnancy.⁽²⁵⁾

This is at least partially due to the effects of exercise on chemicals in your brain known as neurotransmitters.  Exercise helps to reduce excitatory chemicals like glutamate and increase the production of relaxing chemicals like dopamine, helping to improve your state of mind.      

9. Enhanced Body Image

The effect of having your body morph before your eyes can have a negative impact on your body image.

Though some women may come to love how they look while they’re pregnant, others may experience difficulties embracing their changing appearance. ⁽²⁶⁾

Researchers have evaluated the perception of body image in women who minimally exercised and those who trained frequently.

Those committed to frequent exercise throughout their pregnancy demonstrated significantly better perceptions of body image.⁽²⁷⁾

Other researchers have found weight training to be an effective means of improving body image satisfaction in addition to alleviating depressive symptoms in pregnant women. ^(28)(29)(30)

10. Reduce Pregnancy-Related Discomfort

During pregnancy, many women also develop a variety of physical aches and pains.  Several studies, however, show that prenatal weight training is effective for alleviating some of the pain and discomfort many women report experiencing during pregnancy.  ^(31)(32)

In particular, lifting weights can help to reduce swelling in your extremities, which can be a major source of discomfort throughout your pregnancy.  It can also help to strengthen your connective tissue, further reducing the risk or things like sprains and strains.

11.  Decreased Risk of Urinary Incontinence

The hormonal changes that come along with pregnancy can change the lining of the bladder and urethra.

This can lead to a leakage of urine with increased pressure such as coughing and sneezing. Almost 50% of women reported stress incontinence during pregnancy and it may also continue postpartum. ⁽³³⁾

However, research shows that weight lifting in pregnancy can decrease the risk and incidence of urinary incontinence.

Is Lifting Weights During Pregnancy Right For Everyone?

While the benefits may be plentiful, weight training during your pregnancy should be discussed with your obstetrician.  There are a number of health conditions that can potentially make lifting weights dangerous for you and your baby. Such conditions include (but aren't limited to):

• Chronic Bronchitis
• Poorly controlled diabetes
• Morbid obesity
• Intrauterine growth restriction
• Poorly controlled hypertension
• Poorly controlled medical conditions

⫸You Need Previous Training Experienceto Lift Weights During Pregnancy

One of the most important factors to consider in terms of whether or not weight lifting is going to be right for you while you’re pregnant is your level of training experience.  

In order for weight training to be safe and effective during pregnancy, you need to have trained in the exercises previously.  Pregnancy is not the time to commence a workout program if you have never done it before.  

While it may be unfortunate, weight training is not ideal for anyone who has no training experience prior to their pregnancy.  Because your body isn’t accustomed to the kind of stress it will be exposed to during weight training, your risk of musculoskeletal injury greatly increases.

Furthermore, exposing your muscles to challenges they’re not used to can also potentially deplete your baby’s supply of oxygen and nutrients, which may, in turn, increase the likelihood of developmental issues occurring.

How To Lift Weights During Pregnancy Safely and Effectively

If you’ve previously trained and plan on lifting during pregnancy, you may still want to considerworking with a professional with prenatal weight training experience.  

No matter whether you decide to go at it alone or with the assistance of an expert, you’ll still want to consult with your obstetrician before you start a workout routine, no matter how much training experience you have.  

Stay Well Within Your Capabilities

Pregnancy is not the time for making improvements or going for personal records.  Instead, it’s all about maintaining the muscle and strength that you already have.   

In order to keep you and your baby safe, it’s important to stay well within your capabilities on the exercises you’re doing.  Ultimately, that means you may need to lift weights that are lighter than you’re used to.

Focus on higher rep ranges and lighter weights in your training.  Find a weight that you can manageably lift for 10 - 15 reps and make sure that you’re taking adequate rest periods in between your sets.   

You don’t want to be light-headed or completely out of breath after you’ve finished an exercise. That’s a pretty clear sign that you’re pushing too hard.            

Most studies that examined the effects of resistance training during pregnancy were done with light to moderate weights; few studies have used heavy weights. ^(34)(35) Lifting too heavy or too frequently may increase the likelihood of musculoskeletal injury while you’re pregnant.

Extreme lifts may also be dangerous for your baby, however, it's tough to say for sure. Researchers are only beginning to investigate the effects of intensive training like CrossFit during pregnancy. One study in well trained CrossFit athletes did, however, find that women were able to continue heavy lifting up to the third trimester without any adverse health effects. ⁽³⁶⁾

Avoid Exercises Where You're Lying Flat on Your Belly or Back After The 1st Trimester

After the 1st trimester, you should avoid exercises where you’re lying flat on your stomach or back, as they can increase the risk of injury to you and your baby.  

Instead, focus on exercises where you’re seated in an upright or inclined position and don’t use machines that place pressure on your belly.

Stay Away From Exercises that are Strenuous on Your Lower Back

You should also eliminate exercises that place a lot of strain on your lower back after the 1st trimester.  As we’ve already discussed, pregnancy changes your center of gravity and as your belly grows, so does the burden on your back.  

Doing exercises that are extremely taxing on your lower back, in particular, may increase the amount of pain and discomfort you feel both during and following your training.

Exercises to Avoid Later in Pregnancy

• Deadlift
• Clean and press
• Snatch
• Standing overhead press
• Bent over barbell rows
• Flat bench press

Warning Signs to Terminate Training and Consult A Physician

What Kind Of Weight Lifting Routine Should You Do During Your Pregnancy?

Unfortunately, there is no one training program that’s going to be ideal for all pregnant women.   The amount of weight you can lift, as well as the number of sets, reps, and exercises you can do during a single training session, is going to vary depending on your training experience.  

If you have more experience, you may ultimately be able to do a little more compared to someone less seasoned.  However, 3 - 4 days a week of lifting light to moderate weights is generally recognized as a safe range for most healthy women during pregnancy.    

Another reason there's not a one-size-fits-all weight training program for pregnant women is that experience from one exercise to another varies.  If you’ve never done a particular exercise before, pregnancy is not the time to start.

So, with that being said, we’re going to focus on movements that can be done safely during your pregnancy if you’ve previously trained them.  Below is a list of exercises broken down by trimester. We’ve also included recommendations for set and rep ranges for each exercise.  

Like with most exercise programs, we suggest engaging your larger muscle groups first followed by your smaller ones.

First Trimester typical circuit:

Second and Third Trimester typical circuit:

Wrap Up

From reducing the likelihood of intervention during delivery to improving your mental health, lifting weights during your pregnancy can have a number of benefits.  However, there are several factors that will determine whether or not weight lifting during pregnancy is right for you. Ultimately, only those with prior training experience and a clean bill of health are going to be ideal candidates.  

Even if you’re a healthy adult who’s spent plenty of time in the gym, you’ll still need to speak with your obstetrician before starting any kind of weight lifting program.  If you do get the green light from your doctor, it's recommended that you lift conservatively. For many people, that means lifting lighter than you may be used to and avoiding exercises that place you flat on your back or stomach later in your pregnancy.  

• References
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