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Introduction: 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. Materials and Methods: 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. Results: 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. Conclusion: 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.

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Introduction: In this study, antimutagenesis effect of ethanolic extract of propolis by Ames test against two mutagenic substances named azide sodium and potassium permanganate in the presence and the absence of microsomal homogenate of mouse liver (S9) has been investigated. Materials and Methods: In this experimental study at first, different concentrations of ethanolic extract of propolis (0.1-5%) for determining minimum inhibitory concentration (MIC) against tester strains were used. Then by Ames test, antimutagenesis effect was assessed in nontoxic extent. In this test, various strains of Salmonella typhymurium (TA100 and TA97) that contained selective mutation in their operon histidine, were used. Mutant strains (His-) were grown on culture media containing minimum salt and glucose in the presence of mutagen substances above. So only those bacteria that were reversed by mutation (His+) could grow and form colonies on culture media. If antimutagen (EEP) and mutagen substances were gathered, reversed mutation would be reduced and the rate of mutation inhibition could be calculated by means of formula. The differences between the averages of revertants per plate of the sample in relation to the mutagens were analyzed using SPSS software and one-way ANOVA. Results: The resulted MIC values clearly showed that ethanolic extract of propolis at 5% concentration has antibacterial activity against Salmonella typhymurium, but in 0.1-4% concentrations, such effects were not seen. Findings also showed that propolis in such concentrations could neutralize mutagenic effects of those substances in a dose dependent manner. Conclusion: Finally we found that ethanolic extract of propolis that contains different kinds of major and important substances like flavonoids, has good antimutagenic effects and the best concentration for obtaining such effect is in 4% which also was confirmed with microsomal results. The mechanism of antibacterial effect of propolis is complex and it has no analogy to any classic antibiotics, but it should be emphasized that bacterial cell division is inhibited by propolis. Some researchers also argue that propolis could inhibit DNA-dependent RNA polymerase.