The effect of the immersion bath on pain and length of labor

The immersion bath has been used by many health care professionals as a relief method for the pain and discomfort experienced during labor, using a non-pharmacological approach. The objectives of this experimental, controlled, randomized study, are to evaluate the effect of the immersion bath on the pain magnitude in the first stage of labor; to analyze the influence of the immersion bath on the length of the first stage of labor and on the frequency and length of the uterine contractions during labor. The data were collected, from October 2002 to June 2003, in the Normal Birth Center of the Amparo Maternal (a philanthropic maternity hospital) located in the southern region of São Paulo city. The sample was composed of 108 women, 54 in the control group and 54 in the experimental group. The birthing women were evaluated three times: during the initial evaluation, at six centimeters dilatation and then one hour later. In each one of these evaluations cervical dilatation, uterine activity and pain magnitude (verified by the numeric scale and behavioral pain scale) were evaluated. Labor length was calculated in minutes, from the time of six centimeters dilatation to total dilatation. The groups did not present statistical differences related to race, maternal age, gestational age, gestation, labor preparation, marital status, educational level, type of amniotic rupture, aspect of the amniotic fluid, ocitocine use, perineal condition, amniorrexis length, cervical dilatation at the time of ocitocine use, labor length, expulsive period length, ambient temperature, temperature of birthing woman, newborn weight and Apgar scores in the first and fifth minute. With regard to the results, the immersion bath did not present any influence on labor length, which was similar between the groups (p=0.885). Regarding pain magnitude, in the third evaluation the experimental group presented lower scores compared to the control group (p < 0.001) on the numeric scale and on the behavioral pain scale. There was no statistical difference in the frequency of uterine contractions after the immersion bath, among the birthing women of the two groups. However, the contraction length was statistically shorter in the experimental group (experimental 41.9 versus control 44.6). The conclusion was that the immersion bath can be used to offer comfort for women during labor, as long as it offers relief of pain to the women without interfering in the labor progression and without jeopardizing the mother or the baby.