In 2013, a study led by Kendi L. Hensel, Christina F. Pacchia, and Michael L. Smith at the obstetric clinics of UNTHealth has shed light on the potential benefits of Osteopathic Manipulative Treatment (OMT) for pregnant women, particularly in the third trimester.

As pregnancy progresses, women experience significant physiological changes, including increased blood volume and cardiac output. These changes can challenge hemodynamic control, especially during positional shifts that affect venous return to the heart. OMT, a hands-on therapy aimed at improving the function of somatic structures linked to the nervous and circulatory systems, was hypothesized to enhance both autonomic and hemodynamic control in this context.

The study involved 100 pregnant women at 30 weeks gestation, randomly assigned to one of three groups: OMT, placebo ultrasound, or time control. Data from 90 participants were analyzed (25 in the OMT group, 31 in the placebo group, and 34 in the time control group). The researchers measured blood pressure and heart rate during a 5-minute head-up tilt followed by a 4-minute session of intermittent heel raising.

Results indicated no significant differences in blood pressure, heart rate, or heart rate variability between the groups during the tilt, both before and after treatment (p>0.36), nor in heart rate variability between treatment groups (p>0.55). However, a noteworthy finding emerged during the heel-raising exercise: blood pressure significantly increased (p=0.02) and heart rate decreased (p<0.01) following OMT, compared to placebo or time control.

These findings suggest that OMT can acutely enhance hemodynamic control during activities engaging the skeletal muscle pump, likely due to the alleviation of structural restrictions affecting venous return. This improvement holds promising implications for the management of hemodynamic changes during pregnancy, offering a potential therapeutic approach for expectant mothers.

Reference: Hensel, K. L., Pacchia, C. F., & Smith, M. L. (2013). Acute improvement in hemodynamic control after osteopathic manipulative treatment in the third trimester of pregnancy. Complementary therapies in medicine, 21(6), 618-626.