Back pain is a leading cause of pain and disability worldwide, with an estimated financial burden of over $84 billion in the United States alone. Physical, environmental, and psychosocial factors are strongly connected to chronic back pain associated with disability. In addition, the female sex has been consistently associated with an elevated risk of around 13%. A U.S. National Institutes of Health task force has recommended research to characterize its impact by severity, pain interference with activities, and functional status. However, research on the association between childbirth and chronic back pain has yet to be thoroughly evaluated.
Observational studies (where researchers observe what happens to people over time using different sources of information without officially enrolling them in a research study) indicate that 36-72% of pregnant women have acute back pain, with a significant proportion continuing to experience recurring back pain afterwards. Therefore, chronic back pain associated with pregnancy is a significant problem that can affect women for a lifetime. Factors like weight gain, muscular redistribution, ligamentous relaxation (decreased functioning of ligaments) and change in center of gravity may contribute to this increased risk. Most studies of back pain after birth are limited to a few months up to 2-3 years after delivery. Few of these studies have evaluated the correlation between short term back pain immediately after birth and the prevalence, severity, and functional impact of back pain later on.
Researchers Seeking Answers
Researchers in a recent study hypothesized that the occurrence of functionally significant back pain is higher in women who have given birth compared to those who haven’t after taking into account other factors that may create a difference between the two groups. Additionally, a history of childbirth is associated with more severe back pain and short term back pain after birth. If a significant part of the difference between men and women in terms of back pain can be attributed to childbirth, then peripartum periods could be a good opportunity for intervention and helping women. To further research this gap, the researchers tested the hypothesis that pregnancy and childbirth are associated with an increased likelihood of long-term functionally significant back pain.
Health Outcomes Studied
The primary hypothesis was that a history of pregnancy and childbirth would be associated with higher occurrence of functionally significant back pain after taking into account other patient characteristics. The primary outcome was the occurrence of functionally significant back pain for anyone that had given birth. Three secondary outcomes were also assessed: (1) back pain severity before childbirth, (2) occurrence of back pain measuring acute severe back pain within 5 days of delivery, and (3) back pain severity measuring acute severe backpain within 5 days of delivery among women who reported later life back pain. The use of anesthesia for labor and delivery, time of resolution of postpartum back pain, and patient characteristics were also assessed in these secondary outcomes.
Results
Pregnancy and childbirth were associated with an increased occurrence of functionally significant back pain compared to those who had not given birth, even after taking into account age, weight, ethnicity, race, employment and income. Significant predictors for debilitating back pain included pregnancy and childbirth, greater weight, and non-Asian race identification. Age was not associated with the prevalence of back pain.
Women who had given birth reported slightly more severe back pain compared to those who had not given birth. Race, ethnicity and family income were associated with back pain severity, which differed significantly between White and non-White women, as well as Hispanic and non-Hispanic women. Family income level was also associated with pain severity; those who reported a family income of less than $20,000/year reported the most severe back pain. After taking into account other factors to explain the differences, only having given birth and non-white race remained as predictors for back pain severity.
The researchers’ primary hypothesis that a history of pregnancy and childbirth is associated with an increased prevalence and severity of functionally significant back pain among chronic pain patients was supported by their findings. They also found that the association between functional limitation and pregnancy and childbirth remained significant after taking into account a women’s age and race identification. This contributes to current literature by providing evidence that pregnancy is associated with a risk of functionally significant back pain, even decades after giving birth. The findings are supported by previous studies which have demonstrated an association between the number of previous pregnancies and persistent back pain, as well as a study which reported that 68% of women who had back pain during pregnancy reported low back pain later in life.
Their data suggest that a history of childbirth may account for up to 10% of the excess risk in women compared to men for chronic back pain. To reduce this excess, future outcome studies should be conducted on the impact of various non-pharmacological treatment methodologies, such as pain psychology, specifically directed at women at risk.
