comparison of efficiency and some complications of hd and levonorgestrel tables as an emergency contraceptive method

background: this study aimed to define and compare the efficiency and complication between hd and levonorgestrel tablets as an emergency contraceptive method. methods: in this double blind clinical trial, the subjects included 68 women aged 15-45 years with regular menstruation cycles referred to isfahan health centers within the first 72 hours after their unprotected coitus between may to sep 2006. the subjects were selected by convenient sampling and randomly divided into two groups: one taking hd tablets and the other levonorgestrel. the data were collected by 3 questionnaires including demographic, productivity, coitus characteristics, efficiency and some complications such as nausea, vomiting, headache, dizziness and analytic statistical tests ran through spss software. results: levonorgestrel had 100% efficiency in contraception (the difference was significant between two groups). there was no significant difference between changes in menstruation cycle and headache but there were differences considering nausea, vomiting and the times of vomiting within 24 hours after taking the second dose of the tablets; but it wasn't significant during the last six hours. generally, in group of levonorgestrel side effects such as spotting, high amount or severe menstrual bleeding, occurrence and the times of vomiting, nausea severity, headache and dizziness were all witnessed less. discussion: consumption of 0.75 mg levonorgestrel twice as an emergency contraceptive method has higher efficiency in prevention of unwanted pregnancies and lower side effects compared to hd tablets. it is suggested to plan and take necessary actions to produce and distribute these tablets as an emergency contraceptive method in iran.