Back pain is a very common complaint in the latter months of pregnancy for some women. Often the pain is described as a grabbing or stabbing sensation in the lower back near the buttock and base of the spine. Occasionally, the pain can manifest itself down one leg as well. The pain can be so severe that it affects all functions of a normal day-to-day life. Often times this pain is misdiagnosed as sciatica, which is due to impingement of the sciatic nerve, and is highly uncommon in a young healthy pregnant woman with no known prior back pain history. More than likely the cause of this debilitating low back pain is due to sacroiliac joint dysfunction. Pregnancy, in itself, actually amplifies this condition due to the specific hormones that are released in the body which have a direct effect on the ligaments in preparation for childbirth.
Anatomy of the SI Joint
The sacroiliac joint, commonly referred to the SI joint in the clinical setting, is one of two joints on either side of the pelvis where the sacrum, or base of the spine, joins with the large bone of the pelvis known as the ileum. The SI joint is very important as a “shock absorber” during weight bearing activities such as walking, standing up from a chair, and going up and down stairs. Typically the SI joint does not move very much, only about a couple of millimeters during certain activities. It’s movement is a very complex combination of sliding, tilting, and rotating. The stability of the joint comes from being held together by several strong ligaments, which limit the motion of the joint yet stretch just enough to provide the necessary amount of play, or movement, in the joint. As a result of the complexity of movement of the SI joint and difficulty in objectively evaluating the movement, the diagnosis and treatment of SI joint problems can be sometimes overlooked as a causative factor in lower back pain in pregnant women.
The SI Joint During Pregnancy
During a woman’s childbearing years and especially during pregnancy, the hormones relaxin, estrogen, and progesterone are released into the body causing changes in the bony pelvis. Changes include widening of the SI joints with an increase in joint play, which serves the purpose of preparing the pelvis for widening during childbirth. The main hormone responsible for this increase in joint laxity is relaxin. Relaxin causes the ligaments surrounding the SI joint to become more lax, which in turn allows for greater movement of the SI joint. While this movement is important for widening the birth canal, if the movement becomes too great (hyper mobile), the joint becomes unstable during everyday activities resulting in low back pain near the base of the spine. Coupled with the postural changes that occur during pregnancy, the pain can become totally disabling for some women during the latter part of their pregnancies.
Symptoms of SI Joint Dysfunction
Symptoms of SI joint dysfunction include a grabbing or stabbing sensation in the lower back near the buttock and base of the spine during weight bearing activities. Sometimes a vague pain can be felt down the thigh as well. Women may find they have trouble standing up from a chair or getting out of their car. The pain can also be felt while walking, especially so if climbing a hill or walking on an uneven surface. Stair climbing can also be very painful and almost impossible at times. During the night, the stabbing sensation can be felt if laying on one side too long or if trying to turn from one side to the other. Sometimes instability of the SI joints can also cause instability of the pubic symphysis, which is the joint in the uniting the right and left pelvic bones in the front of the pelvis. In this case, pain can seem to radiate to this area as well during weight bearing activities.
Treatment of SI Joint Dysfunction
The more pregnancies a woman has, the higher her chances of developing long-term SI joint pain due to the increased release of the hormone relaxin in the body. Thus, early treatment to prevent hypermobility and wear-and-tear of the joint are essential to avoid a chronic back pain problem from developing. A thorough evaluation of the movement of the SI joints must be completed by a licensed health care provider. Normal motion of the SI joint must be restored in order to obtain long-term pain relief. Typically in pregnancy the joint is too lax, so treatment mainly focuses on stabilization of the joint. Treatment can include a series of pelvic muscle stabilization exercises in order to balance the muscles around the joints. Sometimes pool therapy is beneficial because the exercises can be performed in a non-weight bearing environment without the added stresses of the weight of the baby. Stabilization can also be achieved by wearing a sacroiliac belt which wraps around the hips squeezing the SI joints together, thus decreasing the movement of the joints. Many times the pain goes away shortly after giving birth to the baby, because of the decrease in hormone release and the return of the body to a normal gait pattern. However, there are some women who continue to experience problems following the birth of their baby and need to continue treatment for SI joint related pain.
