Running and Pregnancy Series: Running and Nursing

By on July 28, 2014

Are you a mom who has a recent newborn and is nursing and running?

Returning to running and nursing is a challenge but do-able with good planning, flexibility and realistic expectations. As I am a nursing mom and runner, I began to wonder about nursing and the impact it had on stress fractures and overall short and long term bone health. Research shows that 200 mg calcium/day from the mom will go into breast milk and that this does cause some loss of bone mass at some sights temporarily as long as nursing is continued. But this changes back to normal in most women once nursing is done and resistive and aerobic exercise helps lessen the impact during nursing. Studies also show that a baby’s milk calcium composition is not changed by the mother’ calcium intake or lack of. So that means that baby will take mom’s calcium if there is not enough to go around. In addition, if an individual is both lactating and oligo-amenorrheaic (periods are infrequent), both have been shown to add to decreased bone mass density. Fortunately studies do show that lactation-associated osteoporosis (PLO) is a rare disease entity after lactation is ended. However, no time period was listed in the studies abstracts on when to detect if this is occurring.

What this means for mom:

1. If you have a history of stress fractures already pre-pregnancy and have considered or gone through pregnancy recently, you might already be at a higher risk for developing them while nursing. This depends on the reason-decreased calcium/caloric intake, overtraining, and abnormal menstrual cycle (female triad) all can play a part in this

2. During pregnancy, a baby will leech calcium from the body’s stores and levels may decrease due to this. Both Paula Radcliffe and Kara Goucher had stress fractures during or right after their recent pregnancies. (Radcliffe’s was not reported to occur while pushing baby out during the delivery, but a tailbone fracture can occur in this manner too).

3. Nursing will add to the gamet and as long as you are nursing you will likely be at a higher risk. Once you have discontinued nursing, stores will usually go up given time. (How much time was not stated but the recommended waiting period between pregnancies is ~18 months). But if you jump into another pregnancy with tandem nursing or don’t give your body time to build up again, you may be starting behind the curve in this area. Another thing to consider is whether your cycle has returned normally as hormones will often interplay with this.

4. Possible recommendations are to: take your prenatal vitamin as instructed by your doctor and continue it during nursing and possibly after. Consult your MD and an RD to discuss if more calcium, Vitamin D or other measures are needed. Seek out expert medical advice if you are in the following categories: have had previous problems with stress fractures, pregnancies closer than 18 months, engage in strenuous exercise, are planning to tandem nurse or are finishing nursing close to your next pregnancy, have dietary issues where food is not absorbed well, or have a family history/genetics that may increase the risk for osteoporosis or related issues.

Gremion G1, Rizzoli R, Slosman D, Theintz G, Bonjour JP. Oligo-amenorrheic long-distance runners may lose more bone in spine than in femur. Med Sci Sports Exerc. 2001 Jan;33(1):15-21.

Hirata G1, Chaki O. [Bone loss in lactating women and post-pregnancy osteoporosis]. Clin Calcium. 2011 Sep;21(9):1347-52.

Lin JT1, Lutz GE.   Postpartum sacral fracture presenting as lumbar radiculopathy: a case report. Arch Phys Med Rehabil. 2004 Aug;85(8):1358-61

Lovelady C1. Balancing exercise and food intake with lactation to promote post-partum weight loss. Proc Nutr Soc. 2011 May;70(2):181-4.

Lovelady CA1, Bopp MJ, Colleran HL, Mackie HK, Wideman L. Effect of exercise training on loss of bone mineral density during lactation.  Med Sci Sports Exerc. 2009 Oct;41(10):1902-7.


  1. Amy
    September 18, 2017

    Leave a Reply

    This article was extremely interesting to me because I seem to be okay running a lot soon after pregnancy but as I continue to nurse, I become more prone to femur fractures. I am only hoping that my bones will strengthen back up after I stop nursing. However, my doctor and some studies say that the body doesn’t absorb much calcium through supplements. In addition, higher fracture rates have been found to occur in countries where they eat a lot of dairy and even take supplements. These same countries eat a lot of meat. So I’m wondering if I need to totally change my diet to make sure I get enough calcium. I also wonder how much running I can do before it’s too much. This may be a trial and error process.

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