During pregnancy a whole host of changes occur at every level and in every system of mom’s body - nervous, endocrine, immune, musculoskeletal, and lymphatic. And the biggest changes our patients notice are those in the pelvis. In this post we will discuss the anatomy of your pelvic girdle, changes to your pelvic girdle that occur during pregnancy and why chiropractic care is a critical piece of the prenatal puzzle for so many women.

PELVIC GIRDLE ANATOMY

The adage “structure informs function” rings true for every region of the body and the pelvic girdle is no exception. Let’s cover a few of the anatomical basics. You may have heard of the “pelvic ring” which refers to the bony structures of the left and right os coxae (fused bones known as the ilium, ischium and pubic symphysis) and the sacrum, the triangularly shaped bone that forms the foundation of the entire spine. And you may be familiar with the “pelvic inlet” and “pelvic outlet”, the upper and lower openings that form the funnel-like shape the pelvis is known for. But there is so much more to a baby’s first cradle than the bony structures. So let’s dive deeper into all of the structures that form the “pelvic girdle” so you can understand your pelvis. 

The pelvic girdle has distinct posterior (back) and anterior (front) elements. And changes to one affect the other. The posterior and the anterior elements of the pelvic girdle include:

• The bony pelvic ring for a safe and secure cradle for baby during the prenatal period⁣

• Muscular structures important for movement, support and visceral functions⁣

• Supporting ligaments that stabilize the bony structures of the pelvic ring⁣

• A network of nerves responsible for initiating physiologic, hormonal and immune adaptations during the prenatal period required for pregnancy to progress properly⁣

The muscles involved in the pelvic girdle can be divided into three groups with different functions:

1. Postural support with the spine and trunk

2. Movement of the hip and thighs

3. Support of the pelvic floor and urogenital & gastrointestinal functions

Pelvic girdle stability provided by surrounding ligaments is vital during pregnancy because of a hormone called relaxin. Relaxin loosens and relaxes the body’s muscles, ligaments and joints to allow the body to stretch so the uterus can expand during pregnancy. 

The network of nerves that originate from the lumbar spine and sacral region control all of the organs, muscles, ligaments, arteries, veins of the pelvic girdle. As you would imagine, proper function of these nerves is integral to keeping mom and baby healthy and progressing.

HOW PREGNANCY CHANGES EVERYTHING

As your baby grows, the uterus grows to accommodate them. This stretches everything attached to and surrounding the uterus.

Of the muscular structures in the pelvic girdle there are two of note we will discuss: the iliopsoas muscle and the piriformis muscle. The iliopsoas muscle originates from the lower part of the spine and the inner area of the ilium and attaches to the leg bone. It is responsible for stabilizing and moving the trunk and hip flexion, e.g. bringing the thighs to the chest. Stabilization of the trunk is essential during pregnancy as prenatal posture is notorious for the common pregnancy complaints:

• Neck pain

• Carpal tunnel syndrome

• Headaches

• Lower back pain

• Rib pain

• Pelvic girdle pain

The piriformis muscle is one of the deepest pelvic muscles and its function is hip abduction, e.g. moving the thigh away from midline, and externally rotating the leg. Hip abduction is important during the birth process to make room for your baby. The piriformis muscle has also been implicated in what is called piriformis syndrome where the large sciatic nerve is entrapped that cause issues like:

• Pain in the buttock and hip area

• Pain when getting out of bed

• Inability to sit for a prolonged time

• Pain in the buttocks that is worsened by hip movements

Of the supporting ligaments on the posterior pelvic girdle, the sacrotuberous ligaments on both the left and right connect the sides of the sacrum and the ischial tuberosities or the “sit bones.” Sacrotuberous ligaments are made of strong fibrous connective tissue and they provide stability to the pelvis especially with the rising level of relaxin. On the anterior pelvic girdle are the round ligaments of the uterus which aid in anchoring the uterus and and contribute to maintaining the anteverted (having a forward inclination) position of the uterus during pregnancy. The round ligament contains important uterine vessels, nerves and lymphatics. During pregnancy the growing uterus puts stress on the round ligament which can cause spasms of the round ligament. This can cause round ligament pain felt in the groin region.

Both anterior and posterior joints of the pelvic girdle, i.e. the pubic symphysis joint and the sacroiliac joints are particularly affected during pregnancy due to the shift in the center of gravity and altered biomechanics, noticeable during activities of daily living like walking, exercising, sleeping, laying, getting out of the car, etc. 

Stress to these joints, the muscles and the ligaments of the pelvic girdle create tension and stress to the network of nerves, altering its ability to coordinate the proper function of all it controls. This stress is called subluxation. Subluxation often creates a cycle of stress and dysfunction that often leads to other issues, not just in that original area of stress.

PRENATAL CHIROPRACTIC CARE FOR A BETTER PREGNANCY

Prenatal chiropractic care focuses on reducing the stress on pelvic girdle so mom’s body is more neurologically, physiologically and mentally connected to both her health and baby’s needs. We use INSiGHT scans as a part of our 3-Step Clinical Process to determine where mom’s body has built up stress. Because they only read output, i.e. nothing is being inputted into the patient’s body, it is safe and non-invasive for mom and baby.

All of the doctors at Sprout Family Chiropractic are also Webster Certified by the International Chiropractic Pediatric Association (ICPA) which means they have extra post-graduate training and certification in caring for pregnant mom’s at every stage of pregnancy. The Webster Technique we use to care for pregnant moms specifically addresses all of the structures we discussed. Prenatal chiropractic care improves mom’s health which has lasting effects on baby’s health.

If you or someone you know is looking for a prenatal chiropractor, schedule an appointment with us today!

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References

Wobser AM, Adkins Z, Wobser RW. Anatomy, Abdomen and Pelvis, Bones (Ilium, Ischium, and Pubis) [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519524/

Hicks BL, Lam JC, Varacallo M. Piriformis Syndrome. [Updated 2022 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448172/

https://my.clevelandclinic.org/health/body/24305-relaxin#function

https://my.clevelandclinic.org/health/symptoms/21642-round-ligament-pain

Fiat F, Merghes PE, Scurtu AD, Almajan Guta B, Dehelean CA, Varan N, Bernad E. The Main Changes in Pregnancy-Therapeutic Approach to Musculoskeletal Pain. Medicina (Kaunas). 2022 Aug 17;58(8):1115. doi: 10.3390/medicina58081115. PMID: 36013582; PMCID: PMC9414568.