The effect of maternal bearing-down efforts on arterial umbilical cord pH and length of the second stage of labor.

This study was conducted to compare two types of maternal bearing-down techniques as they relate to the fetal and maternal outcomes of arterial umbilical cord blood pH and length of the second stage of labor. A convenience sample was drawn from the laboring women at a 305-bed medical center who met specific inclusion criteria. Women self-selected to one of two bearing-down groups: spontaneous or Valsalva. Subjects were given specific instructions for the chosen method. The Valsalva group was comprised of 14 subjects, and the spontaneous group was comprised of 16 subjects. The groups were found to be comparable after analysis of several variables. Results of statistical analysis using t-test indicated that, in this small sample, there is no relationship between the second stage bearing-down method and arterial umbilical cord blood pH or length of the second stage of labor. These findings support the conclusions of several studies: using the spontaneous bearing-down method does not have a deleterious effect upon the mother or the fetus. Several recommendations are made for future research based on methodological issues raised during this study.