Does Relaxin Cause Pain During Pregnancy?

preparing for postpartum physical recovery

In the past, we’ve discussed the sacroiliac joint, also known as the SI joint, and its role in pelvic pain and dysfunction. To read our full blog on the subject, click here.  As a brief refresher, the sacroiliac joint is where the sacrum and ilium—the triangular bone at the end of the spine and the pelvis—join together. This space is located just beneath the two dimples in your lower back. The SI joint and its ligaments are frequently overlooked as a source of pelvic pain and dysfunction during pregnancy.

What is Relaxin?

The SI joint is supported and reinforced by strong ligaments. These ligaments also help form the pelvic girdle, a bowl-shaped area of the pelvis that protects and supports urinary, reproductive, and some digestive organs and connects the spine with the legs. The function of the ligaments is to keep the sacroiliac joint from moving too much or incorrectly and keep the pelvic girdle functioning and moving correctly too. During pregnancy, a hormone called relaxin is produced. As its name suggests, relaxin is an essential hormone that relaxes the SI joint, its ligaments, and ligaments of the pelvic girdle, to make room for the growing baby. During pregnancy, the uterus and pelvis also enlarge from the release of other pregnancy hormones, which further stretch the core pelvic muscles and SI joint.

Relaxed pelvic ligaments and lengthened SI joints help ease the process of childbirth but can also have painful effects on pregnant women. Due to postural and musculoskeletal imbalances in some women, relaxin can wreak havoc for the mom-to-be by causing excess strain in the supporting ligaments. About half of all pregnant women experience lower back or pelvic pain due to relaxin causing their joints to move more than usual. We are used to our bodies functioning with “locked” pelvises and SI joints, meaning they are in a stable position while we move and transition between lying down, sitting, and standing. Relaxin causes the joints of the lower back and pelvis to become “unlocked” and less stable as we perform these movements. SI joint-related pelvic pain often manifests in pregnant women as a concentrated pain on one side of the buttocks, back, and/or pelvis and may switch sides and radiate down through the legs and hips, causing weakness. Pelvic pain commonly begins by the 18th week of pregnancy and may intensify as the pregnancy progresses and, in some cases, may become a chronic problem after giving birth.

What Can I Do About SI Joint-Related Pain?

Relaxin and its effects may help to ease your baby through the pelvis during childbirth. However, it’s important to make sure that the not-so-helpful effects of relaxin are addressed after giving birth as the SI joint and its ligaments may be left in an unnatural position and condition. To restore strength and functionality to the sacroiliac joint, musculoskeletal imbalances need to be corrected and the pelvic floor may need some attention and fine-tuning. This is where a pelvic floor physical therapist, like those at Rebalance Physical Therapy, can help! A Rebalance therapist will perform a hands-on exam to evaluate musculoskeletal imbalances and will work to improve the strength and mobility of your pelvic floor and sacroiliac joint. Your physical therapist will create an exercise plan that focuses on strengthening the pelvic girdle and stabilizing your trunk. They will also use pain-relieving techniques, such as myofascial release to ease muscular tension, that complement your exercises. Additionally, the clinician will suggest ways to avoid or minimize pain during your daily movements and activities, such as avoiding sleeping on your back after the 19th week of pregnancy and transitioning safely from a sitting to standing position, to keep your pelvic joints in proper alignment and reduce strain.

Are you pregnant or recently given birth and are worried that your sacroiliac joint may be “relaxin'” just a bit too much? Contact Rebalance Physical Therapy to put your mind at ease and realign your SI and pelvic joints post-pregnancy.

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