Trend of labor progression in multiparous women in Fasa, 2005

Labor refers to the chain of physiologic events that allows a fetus to undertake its journey from the uterus to the outside world. Friedman (1954) describes a sigmoid pattern for labor. This study is carried out to identify the trend of labor progression in multiparous women. The present cohort study was conducted on 336 multiparous women. In order to assess labor stages, dilatation per unit of time was evaluated in each participant. Participants were divided into four groups: non intervention, induced, sedated, and both intervention groups. The related parameters were evaluated in all groups. Data was analyzed using one way analysis of variance, one sample t-test and mixed model regression models in reverse method for drawing the curve. In all groups, with the increasing expansion of cervix the rate of cervix dilatation was increased. A significant relationship was observed between expansion speed rate in active phase of the first stage and the third stage, with induction of labor (p<0.05). But there was no relationship between the second stage and induction. The mean time of active phase and the second stage in this study was significantly higher than women of Freidman study (3.56 hours in contrast to 2.2 hours and 25 minute in contrast to 18 minute, respectively)(p<0.001). Also in the present study the deceleration phase was not seen. Now the pattern of labor progression differs from Freidman's curve in 1950 and has not the sigmoid shape, and the most important factor affecting latent phase is the dilatation of cervix at the time of admission. So determining a standard curve, without bias, is very difficult, and statistical methods should be used to decrease the effect of confounding factors of participants.