The Impact of Prenatal Yoga on Hip Mobility and Delivery Outcomes

Yoga has been shown to decrease lumbar pain, improve maternal mental health, and improve delivery outcomes. While there are many well-established benefits of yoga, the mechanism by which yoga elicits these improvements is unclear. One potential mechanism that has not been studied is through improvements in hip mobility. PURPOSE: The purpose of this study was to test the effect of prenatal yoga on hip mobility. The secondary aim was to determine the relationship between hip mobility and pregnancy outcomes. METHODS: Hip mobility via hip internal and external range of motion and hip flexor muscle length was measured in pregnant females randomly assigned to an experimental or control group. The intervention was a 6-week prenatal yoga program, and all participants were measured pre and post the 6-week time frame. Anxiety and depression were assessed via the State Trait Anxiety Inventory Survey and Perinatal/Postnatal Depression Scale Survey, respectively. After delivery, participants completed a survey on birth outcomes. Data analysis included two-sample t-tests on change scores of objective measures, independent samples t-tests on birth outcomes, and Pearson product correlation coefficients to assess the relationship between hip mobility and pregnancy outcomes. RESULTS: The yoga intervention did not have an impact on hip mobility (right hip flexion, p=0.601; left hip flexion, p=0.629), even when controlling for maternal parity. There was a trending negative correlation between hip mobility and gestation age at delivery (r=-0.385, p=0.085). After six weeks of yoga, the intervention group showed an improvement in anxiety (although not statistically significant) with a mean anxiety score of 36.8 (SD = 7.00). In contrast, the control group’s score increased slightly to 37.9 (SD = 11.49). After six weeks of yoga, the intervention group’s depression score decreased to 6.1 (SD = 5.74) whereas the control group’s score rose to 6.9 (SD = 3.70); however, these data also did not achieve statistical significance. CONCLUSION: The prenatal yoga intervention did not change hip mobility or mental health scores to a statistically or clinically meaningful level; however, these data suggest that a larger sample size is needed, and the positive impact of prenatal yoga is worthy of future study.