The effects of hydrotherapy on anxiety, pain, neuroendocrine responses, and contraction dynamics during labor.

BACKGROUND: Hydrotherapy (immersion or bathing) is used worldwide to promote relaxation and decrease parturient anxiety and pain in labor, but the psychophysiological effects of this intervention remain obscure. DESIGN: A pretest-posttest design with repeated measures was used to examine the effects of hydrotherapy on maternal anxiety and pain, neuroendocrine responses, plasma volume shift (PVS), and uterine contractions (CXs) during labor. Correlations among variables were examined at three time points (preimmersion and twice during hydrotherapy). METHODS: Eleven term women (mean age 24.5 years) in spontaneous labor were immersed to the xiphoid in 37 degrees C water for 1 hr. Blood samples and measures of anxiety and pain were obtained under dry baseline conditions and repeated at 15 and 45 min of hydrotherapy. Uterine contractions were monitored telemetrically. RESULTS: Hydrotherapy was associated with decreases in anxiety, vasopressin (V), and oxytocin (O) levels at 15 and 45 min (all ps < .05). There were no significant differences between preimmersion and immersion pain or cortisol (C) levels. Pain decreased more for women with high baseline pain than for women with low baseline levels at 15 and 45 min. Cortisol levels decreased twice as much at 15 min of hydrotherapy for women with high baseline pain as for those with low baseline pain. beta-endorphin (betaE) levels increased at 15 min but did not differ between baseline and 45 min. During immersion, CX frequency decreased. A positive PVS at 15 min was correlated with contraction duration. CONCLUSIONS: Hydrotherapy during labor affects neuroendocrine responses that modify psychophysiological processes.