Objective: Investigation the success rate of Estradiol in combination with Misoprostol in labor induction Design: Noting to Estradiol leads to an increase in Prostaglandin production, and Prostaglandin has a important role in onset of labor, we decided to investigate the effect of Estradiol on induction of labor. Setting and conduct: This study is a prospective clinical trial, double blind and randomization, with control group. The study will be performed in the Hospitals of Mashhad University of Medical Sciences on pregnant women who gestational age is upper 36 weeks and cervix is undesirable , and has indication of the termination of pregnancy will be done. The randomization is done by using closed envelopes by placing the referee for treatment in the envelope. Inclusion criteria included: Gestational age over 36 weeks, singleton pregnancy with a vertex presentation, the absence of contraindications to vaginal delivery, there is no indication for emergency childbirth, no history of liver and kidney disease, no history of fetal distributors, no history of contraindications use Misoprostol (such as the mother's risk of blood coagulation disorders, asthma, glaucoma, etc.).