A mother’s struggle: what is happening to my spine and joints during pregnancy?

It’s no secret that the body goes through tremendous changes during pregnancy.  What is not often known is that it takes nearly another nine months for the body to return to normal (kind of)  after having a baby.   Many of these changes set mothers up for back pain during and after pregnancy, and understanding what happens to our bodies can help us to better take care of ourselves.

Back pain is not as benign as we may think. In fact, it is a significant cause of health issues in the United States and worldwide. In a 2010 study of the global burden of disease, low back pain was found to cause more global disability than all of the other 290 conditions studied (Hoy, D, et al. “The Global Burden of Low Back Pain: Estimates from the Global Burden of Disease 2010 Study,” Ann. Rheum. Dis., Mar. 2014). 

Back pain is very common both during and after pregnancy, with half of women experiencing back pain at some point during pregnancy (Ostgaard, H.C., et al. “Prevalence of Back Pain in Pregnancy,” Spine, May 1991, 549-52), and approximately 40% of women experiencing back pain after giving birth (Ostgaard, H.C., et al. “Postpartum Low-Back Pain,” Spine, Jan. 1992, 53-5).

These statistics on pain both in and after pregnancy reveal to us the significance of the issue. In order to know how to deal with it, we have to understand the changes to a woman’s body during pregnancy. 

One of these physiologic changes is as a woman’s body grows to adjust to the growth of the fetus, her abdominal muscles stretch. This often causes a diastasis, or in simpler terms, a split, in the rectus abdominis. The abdominal muscles that are split in this process are critical to the stabilization of the spine, leading to women having less stability in their spines after pregnancy. 

In addition to this stretch, while a woman is pregnant, the ligaments of her lumbar spine and pelvis loosen to allow for safe passage of the baby through the birth canal during birth. This too decreases the intrinsic stability of the spine.  

Further, the S-shaped curve of the back increases in pregnancy, which puts additional pressure on the low back. The pelvic floor muscles become stretched, and in turn, weakened. These muscles function as a crucial floor for the body’s core muscles, and this muscular weakening negatively impacts the strength and stability of the spine overall. 

Finally, there are two important nationwide changes that increase pain in pregnancy– the fact that women are now becoming pregnant at older ages, and the national increase in the rate of pregnancies of multiples (twins, triplets, etc.).  Older age of motherhood means that some women already suffer from back pain before pregnancy, and increased multiples just adds more pressure on the body.  These two factors increase the baseline risk for back pain during and after pregnancy, and place women at increased risk for chronic back pain if their problems are not addressed early.