There are a lot of amazing things that occur in the female body during pregnancy.  Things like the uterus growing 500 times its size, from the size of a peach to that of a medium watermelon, to a 50 percent increase in blood volume and 20 percent more red blood cells being produced to growing a completely new organ, the placenta.  Hormonal shifts also occur to prepare the woman’s body to grow a healthy baby and to prepare her body for delivery.  Relaxin is a hormone produced by the ovaries and the placenta.  Relaxin loosens and relaxes muscles, joints and ligaments to support the woman’s body to grow and stretch during pregnancy.   

50% of all pregnant women experience back pain during their pregnancy.  Where does the low back pain, sacroiliac pain and sciatica come from? 

There are several causes and most times it isn’t just one thing but a combination of factors. 

As the baby grows, the changing load distribution in the abdomen can put additional stress on the low back and pelvis joints.  Pressure, traction or stretching of the organs and structures in the lower abdomen and pelvis can cause referred pain and secondary muscle spasm to the low back and pelvis.

The sacroiliac (SI) joints are the joints between the sacrum and the ilium bones in the pelvis.  The SI joint is held together with ligaments.  There aren’t any muscles that crosses the joint posteriorly to give the joint extra stability.  The SI joint relies only on the ligaments for stability.   Just like any joint in the body, there needs to be movement in the SI joint for proper function.  During pregnancy and the increased production of relaxin, the SI ligaments become loose allowing for more movement.  With more movement of the SI joint comes more possibilities for restrictions or subluxations to occur in the SI joint.  When the SI joint becomes subluxated or locked, this causes a sharp stabbing pain in the joint.  Sharp pain when sitting, getting up from a seated position and standing still are textbook signs of SI subluxation.  Walking can give some SI pain relief but not always.  A subluxated SI joint can also mimic sciatica pain radiating down the posterior leg. 

A subluxated SI joint doesn’t always cause pain either.  When the SI joint is locked up, it causes the sacrum to rotate and forces the lumbar spine to compensate.  The lumbar spine can also rotate and cause the muscles in the low back to become tight and tender.   The lumbar spine, sacrum and SI joints all work together and influence each other.  The cause of the low back or pelvic pain can originate in the lumbar spine, sacrum or SI joint.  When one region is subluxated, it can negatively influence the others and become symptomatic.   The potential for these symptoms increases in the second and third trimesters as the baby grows and puts more mechanical stress on the mothers low back, pelvis and internal structures in that region.  

This is why receiving chiropractic care during pregnancy can help the future mother with her low back pain, SI pain or sciatica.  Studies have shown that 84% of women who see a prenatal chiropractor report less back pain than women who don’t.  Regular chiropractic care during pregnancy keeps your structure properly aligned and takes the stress off your musculoskeletal system, which makes you feel better. 

Dr. Keith Giaquinto practices in Naperville, IL.  He treats pregnant women not only for low back pain, SI pain or sciatica but for other pregnancy related issues like heartburn, nausea/morning sickness, insomnia, edema, etc.  Dr. Keith specializes in Internal Health and can support women during their pregnancy from a functional approach. 

Journal Chiropractic Medicine. 2007 Spring; 6(2): 70–74.  PMID: