This is the last entry in BUMP Life’s 4 part series on prenatal fitness.  If you have missed any of our past posts on the most frequently asked prenatal fitness questions, check them out here:

4 Top Prenatal Fitness Questions

  1.  Can I get my heart rate over 140bpm
  2.  Can I do ab work while I am pregnant?
  3.  I woke up last night on my back, should I be worried?

And on to our last frequently asked question:

My joints feel loosey-goosey, should I avoid working out?

Ahhh, Relaxin, you are the culprit.

There is a laundry list of symptoms and sensations you may experience while you are pregnant; nausea, unstable joints, swelling, light headedness, back pain and many more and most can be traced right back to the effects of the hormone, Relaxin.

This topic is near and dear to my heart.  When I became fascinated with prenatal fitness many, many years ago, it was Relaxin that fascinated me the most.

Relaxin does exactly what it says it does- it relaxes.   

Its main job is to relax the connective tissue in the rib cage so your ribs can expand to accommodate the growing baby.  It also relaxes the pelvic joints to allow for delivery.  It does not, however, limit its self to just these joints.  It relaxes the ankle joint and the pinky finger joint and the joints in the spinal column.  It also relaxes muscle fibers and various sphincters in the body.

SO relaxin is responsible, in part, to everything from morning sickness, to heartburn, to that increased chance you’ll twist your ankle stepping off the curb.

So what does this mean for working out?


Relaxin effects working out in 3 main ways.  But in short– working out will help mitigate the less desirable effects of relaxin. SO KEEP WORKING OUT!


Injury Prevention-

Strong muscles will help prevent injuries during pregnancy

Relaxin cause the connective tissue around the joints to be a little looser.  This makes sense, so the rib cage can expand the pelvic bones can separate.  But it also makes you a little more susceptible to spraining an ankle or experiencing wrist pain.

Take care not to over-tax weak joints.  Moves with quick direction changes or lots of lateral movement (think fast paced tennis match) are more likely to cause an injury.

In your daily life, slow down a bit and take more caution on unstable surfaces where tripping hazards (rocks, curbs, kids toys) may cause you to loose your footing or balance.

Strong muscles will help support less stable joints. Going into your pregnancy strong is ideal, but weight training during pregnancy will insure the muscles surrounding your joints are strong and able to support your body, even when your joints are not.

Underfil Issues and Dizziness


Exercise improves circulation, which may decrease nausea

In the first trimester, relaxin shows its effects by relaxing the muscle fibers.  When the muscles do not provide as tight a ‘casing’ for the blood vessels that pass through them, the blood vessels also expand.  With larger blood vessels, there is now not enough blood to fill up the increase space, leading to an underfill issue.  Gravity causes the blood to pool in the lower extremities (hello swollen ankles) and makes it harder on your body to pump blood quickly all the way up to your head, therefore leading to feelings of dizziness, lightheadness and nausea.

The good news is, your body gets to work quickly producing more blood.  By the end of your first trimester, your blood volume has increased by 30-50 percent!  Once the blood volume has a chance to catch up, many of the dizzy spells subside.

During the first trimester, take caution when standing up quickly and especially when going from a head down position like downward dog or blow-drying your hair.  And try a gentle walk even if you feel nauseous, exercise improves circulation and getting some blood to your brain might help the symptoms of morning sickness.

Postural Concerns

 It is never to early in your pregnancy to start practicing proper posture, even though it really becomes a concern in later trimesters when increase weight adds to compromised joints.  Increased size of your belly has a tendency to pull your body forward, causing an excessive curve in your lower back (and increase back pain).  Weakened spinal joints and increase weight of your breast can cause your shoulders to round forward (leading to more back pain).

Start as early as you can practicing proper posture.  Don’t slouch.  Keep your shoulders pulled back and engage your abs, think about hugging your baby closer to your body.  This will help improve your posture, prevent back and neck pain and actually make you look smaller.

Check out these pregnant pictures of a friend of mine.  How far along does she look in each photo?


Did you guess 36 weeks….in BOTH??  The first photo shows good posture and the second photo shows bad posture.  Enough said.

Thank you so much for tuning in to this series on Prenatal Fitness.

My bottom line points about exercising during your pregnancy are;

  1. Do it, it is good for you and good for your baby
  2. Be reasonable, find exercises that you like and feels good.  Don’t feel like you have to keep up with your old routine or what some celebrity is doing if it doesn’t feel right to you.
  3. Be smart, fitness during pregnancy is safe and important, but that doesn’t mean you don’t need to know what you are doing.  Find someone who can help you put a safe, effective, appropriate routine together to avoid injury and make sure you can stick with it.  (check out BUMP life for more suggestions)

Stay tune for more articles on specific exercises to do during pregnancy and afterwards.