Common pregnancy injuries: causes of pain for mothers-to-be

Orthopedic injuries exacerbated when mothers are expecting

PREGNANCY IS ASSOCIATED WITH A WIDE VARIETY of physiological, hormonal and anatomical changes that prepare the body for sustaining the developing fetus and preparing for labor and delivery. These changes begin after conception and affect every aspect of the body. For most women these adaptive changes return to their former state a few weeks after the pregnancy with minimal residual effects. 

Adaptations take place in every organ system including pulmonary, cardiac, renal, endocrine and hematological systems. We will focus on the effects these organ systems have on musculoskeletal pain and identify the common orthopedic conditions experienced in the pregnant patient population.  

Common musculoskeletal causes of pain during pregnancy

The most frequent musculoskeletal complaints during pregnancy were found in research to be low-back pain, hand-wrist and hip pain. Musculoskeletal pain and symptoms were also found to be experienced most in the third trimester compared with the first and second trimesters, with the exception of elbow, shoulder and neck pain.¹ 

Soft tissue swelling is commonly experienced during the last eight weeks of pregnancy. The woman’s fluid status increases during pregnancy. Blood volume increases, as does intracellular and extracellular fluid. Fluids accumulate more during the day and dependent swelling is a common occurrence. Hormonal fluctuations, fluid accumulation with a tendency to edema, nerve hypersensitivity and glucose level fluctuations are also factors that predispose pregnant women to compressive neuropathies.²  

Since fluid cannot be compressed, an accumulation of fluid in an anatomical area with limited space can result in nerve compression syndromes. One common nerve compression syndrome seen during pregnancy is carpal tunnel syndrome (CTS). This syndrome commonly occurs during the last trimester of pregnancy. Pregnancy-related CTS is the most frequent mononeuropathy during pregnancy. The incidence of CTS in pregnant women is more common than in women who are not pregnant. The telltale clinical signs of CTS are numbness and tingling in the thumb, index and middle fingers. Weakness of thumb opposition often results in hand dysfunction. The accompanying symptoms wake women up at night and interfere with restful sleep. 

Although not as common, the ulnar nerve can become compressed in the canal of Guyon’s with a similar mechanism to median nerve entrapment. Common patient presentation is numbness and tingling of the fourth and fifth fingers and possible weakness of the interosseous muscles. 

A common site of nerve compression in the lower extremity occurs at the tarsal tunnel in the ankle. The posterior tibial nerve vein and artery travel with the flexor tendons to the foot under a dense fibrous tissue located posterior to the medial malleolus. Common symptoms of tibial nerve compression include numbness and tingling in the medial aspect of the foot with possible weakness of the flexor muscles to the toes. 

Another condition frequently occurring in the lower extremity is leg muscle cramps. Leg muscle cramps are typically experienced at night time and during the third trimester. 

Common symptoms from uncommon causes

Serdar reported that 34% of pregnant women experienced hip pain.¹ Many pregnant women experience hip pain in their second or third trimester. It may result from the increase in mechanical load to hip joints in later stages of the pregnancy.  

However, some specific disorders should also be assessed. In a pregnant woman presenting with hip pain, pubic pain, transient osteoporosis of the hip or avascular necrosis of the femoral head must be included in the differential diagnosis. It has been hypothesized that higher adrenal cortical activity combined with the increased mechanical stress of weight gain may contribute to its etiology. Symphysitis, osteitis pubis and pubic stress fractures are also clinical possibilities in expectant patients with hip pain. 

During pregnancy, it’s common for women to experience foot problems they may have never experienced before. Over-pronation and edema often develop during pregnancy. Natural weight gain puts added load on the knees and ankles, which can lead to heel pain, arch pain and anterior foot pain. Custom orthotics that support all three arches of the feet and accommodating, well-fitted footwear can go a long way in easing foot pain, relieving lower extremity fatigue and normalizing lower extremity mechanics. 

Mechanism of back pain during pregnancy

Anterior translation of the cervical spine and extension of the occiput on the atlas can occur and be related to muscle spasms and suboccipital headaches resulting in cephalgia. Also, increased thoracic kyphosis, anterior translation of the head and the increased weight of the breast tissue may cause cervicothoracic pain, radiculopathy, thoracic outlet syndrome and myofascial pain.³ 

Low-back pain is a common complaint during pregnancy and labor. It has been reported that approximately 50% of all pregnant women experience back pain during their pregnancy and 50-75% of women experience back pain during labor.⁴ Low-back pain is due to a variety of contributing factors. An altered center of gravity due to a steadily growing fetus, uterus and breast tissue are key factors that contribute to the physical demands of pregnancy. The additional weight gain of 25-35 lbs. greatly increases the stress to the low back and sacroiliac joints.  

Lumbosacral pain may be secondary to sacroiliac strain. The pelvis rotates about a fulcrum located at the second sacral segment. Typically, the strong sacroiliac ligaments resist this forward rotation, but as the center of gravity shifts, anteriorly pelvic rotation increases, causing an increase in lumbar lordosis. Simultaneously, the ligaments become increasingly relaxed due to an increase in circulating progesterone, estrogen and relaxin throughout pregnancy. This occurs more so during the third trimester. The increased ligament laxity facilitates increased movement, decreased spinal stabilization and additional strain on the ligaments and their attachments to the ilium.  

As lumbar lordosis increases during the later stages of pregnancy, extra stress is placed on the intervertebral disks and facet joints. An increase in lumbar lordosis also increases the activity of the iliopsoas muscles. The piriformis muscle remains in a contracted state to maintain the external rotation of the legs, which creates a wide base of support to compensate for the developing decreasing balance due to the shift in the center of gravity. As the body continues to adapt, the sagittal curvature of the rest of the spinal column increases as well.³ 

Direct pressure of the fetus on the lumbosacral nerve roots may also be a cause of pain.⁵ Physically strenuous work and previous low back pain are factors that may also be associated with an increased risk of developing low-back pain and sacroiliac dysfunction during pregnancy.⁶ All of these factors contribute to back pain experienced by pregnant patients, leading many to seek chiropractic care.

MANUEL DUARTE, DABCO, DABCSP, DACBA, MSAc, MS, is an international lecturer, author and researcher. He is a graduate of Long Island University and the National University of Health Sciences (NUHS), and a professor emeritus at NUHS. He is the previous owner of Body Fitness Physical Medicine and Sports Injury Clinic.

References 

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