The Effect of Lower Extremity Asymmetries on Low Back and Lower Extremity Pain with Pregnancy

Abstract

Approximately 50% of pregnant women experience low back and lower extremity pain during pregnancy, many of which continue to experience pain postpartum. It is known that many women experience changes in foot size, arch height and lower extremity alignment. However, the mechanism by which these changes are related to pain is relatively unknown, specifically in regard to asymmetric changes in alignment. Therefore, the purpose of this study was to assess alignment during pregnancy in order to determine if asymmetries occurring in women during pregnancy are related to low back, hip, knee, and foot pain. Methods: Ten women in their third trimester of pregnancy and nine nulliparous controls were recruited to participate. Biomechanical measures of foot length, foot width, arch index, arch height index, arch rigidity index, arch drop, and rearfoot angle were taken bilaterally to assess asymmetry. Pelvic asymmetries were assessed in the frontal and sagittal plane. Musculoskeletal pain was assessed using a Visual Analogue Scale. Pregnant women were placed into a 'pregnant pain' group (n=5) and a 'pregnant no pain' group (n=5) based on results of this scale. Results/Conclusion: A relationship between lower extremity asymmetries and pain during pregnancy does exist. Specifically, negative correlations were found between arch index asymmetry and low back pain (p=0.005), foot length asymmetry and lower leg pain (p=0.008), and pelvic obliquity and lower leg pain (p=0.020). Significant positive correlations were found between foot width asymmetry and knee pain (p=0.028), as well as arch drop asymmetry and upper leg (p=0.024), knee (p=0.005), and lower leg pain (p=0.019). This study was successful in identifying a few target areas for clinicians to treat pain, but requires a much larger sample size in order to establish differences between pregnant women who experience no pain and pregnant women who do experience pain. Because low-back and lower extremity pain is extremely prevalent in post-partum women, it is important to conduct further research in order to determine both whether these asymmetries are related to pain post-partum, and if treating these asymmetries is preventative of pain post-partum.

The Effect of Added Weight on Foot Anthropometry in Pregnant Women and Nulligravida Women

“…More than half of women report leg and foot pain during a pregnancy (9), with the incidence of pain increasing with the number of pregnancies (31). Pregnancy leads to long-term changes to foot structure and function, and these changes may be related to the incidence of pain (10,14,32). Thus, prevention of these physical changes to foot anthropometry may be of clinical concern.…”

The Effect of Asymmetry on Pregnancy-Related Pain in the Postpartum Period

“…In a study on pelvic alignment in pregnant women, Harrison (29) reported that nonpregnant controls tended to have greater pelvic obliquity than the pregnant group over the three trimesters, but the analysis could not decipher which groups were significantly different. Casto (15) found no trend or significance for pelvic asymmetry between pregnant women in pain and those not in pain. Casto (15) also measured iliac crest height in a seated position to remove leg length discrepancy, and found no significance between pregnant women in pain, pregnant women not in pain, and nulliparous controls for the even and uneven iliac crest heights.…”

“…Postpartum subjects with pain greater than three out of ten were placed in the postpartum pain group (15). Postpartum subjects with no pain or less than three out of ten on the VAS were placed in the postpartum no pain group.…”

“…Left-right arch rigidity index (ARI) asymmetry was correlated to pain in the upper knee and leg pain, and arch index asymmetry was correlated with overall lower extremity pain during pregnancy (29). Casto (15) reported a trend towards a higher ARI asymmetry in pregnant women, but cautioned that measurements may be affected by swelling during pregnancy.…”

“…Although several studies have examined the alignment of the lower extremities and its relationship to pain in pregnant women (4,14,15), there are limited data on the relationship of the asymmetries and pain from pregnancy relating to chronic pain postpartum. A careful review yielded only one study that examined the relationship between peripheral joint laxity and postpartum back pain (16).…”