The medication misoprostol is used to facilitate the entry into the uterus of hysteroscopy surgery equipment and this research aims to compare the results of the use of this drug in two different doses trying to find the optimal one.

To perform this work we will use the misoprostol and will perform a questionnaire that will be asked during hospitalization, before, during and the 12hours after the surgery.

The patients who meet the inclusion criteria after signing the Informed Consent Form will be allocated into two groups getting misoprostol 200mcg or misoprostol 800mcg.

Background: Hysteroscopy represents a minimally invasive procedure that has been increasing its adoption in the treatment of many cervical canal and uterine cavity disorders. However, difficulties related to the introduction of the equipment through the cervix are frequent. Although several studies suggest advantages in the cervical preparation with misoprostol, reducing the resistance of the uterine cervix, systematic reviews are unison to indicate the need for clarification on the ideal dose.

Aim: Compare the intra and postoperative results of patients submitted to cervical dilatation for surgical hysteroscopy with previous use of misoprostol at doses of 200mcg or 800mcg for uterine cervix preparation at Recife school hospitals.

Methods: Randomized, quadruple-blind clinical trial with patients who underwent cervical dilatation prior to surgical hysteroscopy at Recife school hospitals, Pernambuco. Patients included will be allocated randomly into two groups. The first group will use misoprostol in the dosage of 200mcg and the second, will use the dosage of 800mcg. Administration, via the vaginal route, will occur 12 hours before performing the operative hysteroscopy. The following variables will be studied: cervical canal width, cervical length, degree of difficulty, duration and failure of cervical dilation, side effects, surgical complications and patient's satisfaction. For statistical analysis, chi-square tests of association, Fisher's exact and Mann-Whitney tests will be used to compare the groups, with an alpha error of less than 5% being considered significant.

Ethical aspects: This study will comply with Resolution 466/12 of the National Health Council and was submitted to and approved by the Professor Fernando Figueira Integral Medicine Institute Research Ethics Committee, beginning only after this approval. All participants will only be included if they voluntarily agree to participate by signing the Free and Informed Consent Form.

There are no conflicts of interest.

Inclusion Criteria:

• Patients with indication for operative hysteroscopic.

Exclusion Criteria:

• Patient with contraindications to the use of prostaglandins such as asthma, glaucoma, renal failure, severe heart disease or drug allergy;
• Situations that impede the vaginal administration of medication such as major genital prolapse and virginity;
• Situations that prevent hysteroscopy as major uterine bleeding, diagnosis or suspected topical pregnancy and genital infection such as vaginosis and cervicitis;
• Situations that may influence cervical canal width such as a history of isthmo-cervical incompetence or major cervical surgery like conization or trachelotomy; presence of any structure like uterine fibroid or endometrial polyp inside the cervical canal or though the cervical os; patients on systemic or vaginal estrogen replacement therapy or who have recently used gonadotropin hormone-releasing hormone analogues.