Pretty much all of the pregnancy exercise guidelines I’ve read very explicitly state that a woman should not engage in heavy weight lifting during pregnancy. I’ve seen some amazingly arbitrary numbers tossed out there, such as one well-known website that suggests pregnant women not bench press more than 40 pounds. What?! Oh, of course: obviously, all pregnant women have the same level of strength; therefore a one-size-fits-all recommendation is completely appropriate. Sigh.
Personally, I believe that weight training during pregnancy is of critical importance for the maintenance of core strength, bone density and joint integrity, and for the prevention of muscle atrophy (shrinkage). Doesn’t it make intuitive sense that a program of moderately heavy deadlifting might actually help develop the lower back strength necessary to support a growing baby, or that a squatting program will greatly assist a woman to more comfortably labour in the squatting position? And after the birth — lifting baby, putting baby down, carrying baby for long periods of time, lifting strollers in and out of the car, bending over to pick up toys — the applications are endless.
If you’ve been following my blog thus far, you will know that early into the second trimester, I am still lifting relatively heavy weights — in some cases (depending on the lift and on how I’m feeling that day) as much as 95 percent of my pre-pregnancy one rep max. I intend to continue to lift throughout my pregnancy, making ongoing modifications as my body changes.
Now, this is not to say that there aren’t some fundamental considerations for weight lifting during pregnancy, but I think it’s important to remember that an experienced lifter (e.g. someone who has been doing CrossFit for a couple of years) is going to have much different limitations than the “biceps curls with pink rubber weights” set, which is why a one-size-fits-all approach simply doesn’t work.
Below, I will outline some of the factors to take into consideration when pursuing a lifting program during pregnancy. I do not believe in setting absolute limits; rather, I support the idea of using common sense and self-awareness to determine one’s own individual limitations on any given day. In other words, use these guidelines to know what to be aware of, but use your intuition to tell you when to pull back or stop.
1. Lying on your back. Somewhere between the twelfth week and the start of the third trimester (most sources say around 12-16 weeks), the uterus becomes large enough that when you lie flat on your back, it can exert pressure on the vena cava — the vein that returns blood from your lower body to your heart — which reduces blood flow and may cause acute hypotension (lowering of blood pressure). Lying on your back for too long is believed to interfere with the flow of blood and nutrients to the placenta, with the implication that this could be harmful to the developing fetus (note that there is no clinical proof whatsoever of this being dangerous, and that even the American College of Obstetricians and Gynaecologists only cautions against extended periods of supine lying). If you feel good and your stomach is not yet very large, bench presses may still be an appropriate exercise for you after the first trimester, as long as you keep your sets relatively short and make sure to sit upright or stand in between sets. Push-ups make a great pregnancy alternative to the bench press. If your belly gets in the way, dumbells or yoga blocks placed under your hands can help to raise you up a few inches. Weighted push-ups using a weight vest or some bumper plates placed on your mid back can provide an extra challenge that approximates heavy bench presses.
2. Valsalva manoeuvre. A valsalva manoeuvre is a forced exhalation against a closed airway. It is useful in equalizing pressure in the ears, and in the achievement of heavy one rep maximum lifts 🙂 It also causes a sudden spike in blood pressure, and may result in dizziness. Valsalva manoeuvres are not recommended during pregnancy. Instead of holding your breath during lifts, try using a regular pattern of exhaling during the concentric (resistance) phase and inhaling during the eccentric (negative) phase. The main implication here is that you will probably have to reduce your weights from pre-pregnancy levels in order to accommodate a continuous breathing pattern.
3. Balance. During pregnancy, your body is growing, your centre of gravity is constantly shifting, and hormonal changes may interfere with mental concentration. This results in many pregnant women becoming rather clumsy and prone to falling… and the last thing you want to do during pregnancy is lose your balance and fall over with a heavy, loaded bar! Balance is an important consideration in the overhead squat, as well as the ballistic lifts: the snatch, the clean and the jerk. As your pregnancy progresses, you might even start to find that balance becomes an issue in front and back squats — especially if your technique pre-pregnancy was less than perfect. Don’t be afraid to reduce your weights to whatever level is necessary to ensure your safety — even if this means using a training bar or wooden dowel for overhead squats, cleans, snatches and jerks, and switching from weighted front/back squats to air squats (body weight only). Eventually, you many find that you feel uncomfortable or unsafe performing ballistic lifts, and if that’s the case, simply discontinue them for the remainder of the pregancy.
4. Hormones. Beginning as early as two weeks after conception, and possibly lasting as long as three to five months post-pregnancy, the hormone relaxin works to slacken supportive tissues in a woman’s body. This allows the body to stretch to accommodate the growing fetus, and also allows the joints of the pelvic girdle to ease in anticipation of labour and delivery. While this is obviously a desirable effect, it does have implications on a woman’s prenatal exercise capabilities. Because relaxin causes a softening of ligaments (especially those supporting the joints), pregnant women must use caution in conducting ballistic movements and movements that exercise the full range of motion of a joint. In early pregnancy, you will want to start to scale back the weights of your cleans, jerks and snatches, and in later pregnancy, depending on how your joints are feeling, you may even want to avoid them altogether. You will also want to avoid doing max load squats (especially below parallel), since your knees and hip joints will not be as stable as they were pre-pregnancy, and relaxin reduces the amount of elastic energy available to propel you back up from the bottom of the squat.
5. Physiology. As your belly grows, you might find it difficult to perform standard deadlifts, cleans and snatches. Using a sumo (wide) stance for deadlifts, and using dumbells or kettlebells for cleans and snatches can help you safely continue to perform these lifts while accommodating your growing belly.
6. Lower back strain. Deadlifts, done consciously, with an appropriate amount of weight and with proper form, do not cause back strain. Leaning over to pick up a pencil off the floor might hurt you if you’re not being careful, but a properly executed deadlift is a safe movement. A couple of lifts that might be aggravating if you are experiencing pregnancy-related lower back pain, however, are the overhead press (shoulder press, push press and push or split jerk) and the clean, especially if you have a tendency to lean backwards and let your hips shift forwards when straining to execute or catch heavier lifts. This can be easily remediated by reducing the weight to one which you can perform comfortably and safely, and by focusing on keeping your hips back and your spine in a neutral position.
In summary, lifting during pregnancy is a safe and essential activity, that when executed with careful attention and proper form, can help to reduce pregnancy aches and pains, and may even ease the process of labour and delivery. But pregnancy is not a time for egos, nor a time to be setting personal records (save that for a few months post-delivery, when your body will experience its biggest surge in human growth hormone since puberty!). Your pregnancy lifting program needs to be guided by a combination of common sense, intuition, impeccable technique and ongoing modification. And unless you are a strong, confident and experienced lifter, I would highly recommend enlisting the guidance of an expert trainer, who can both ensure correct form and assist you with the necessary modifications as your pregnancy progresses.