Examining the Evidence
Does self-administered misoprostol prime the cervix for hysteroscopy?
YES in a premenopausal woman. However, the ideal dosage is yet to be determined.
In this randomized, placebo-controlled trial by Oppegaard and colleagues, when 1,000 μg of vaginal misoprostol was self-administered by premenopausal women at least 12 hours before operative hysteroscopy, significant cervical ripening occurred, with increased cervical dilatation and less difficulty with dilatation, compared with women given placebo.
The drug was ineffective in postmenopausal women.
Operative hysteroscopy is a common, minimally invasive procedure used to treat a number of gynecologic pathologies.1 The procedure requires that the cervical canal be dilated enough to allow passage of the hysteroscope.
Misoprostol is a prostaglandin E1 analog. It also is an effective cervical-ripening and labor-induction agent used during pregnancy in the second and third trimesters.2,3 Earlier studies suggested that misoprostol may be promising as a cervical-ripening agent before hysteroscopy in premenopausal women, although further research is needed to determine the ideal dosage, route, and timing of administration.1,4-6 Most of the studies demonstrating benefit with misoprostol before hysteroscopy have involved intravaginal dosages of 200 to 400 μg given 8 to 12 hours before the procedure.1,4-6
Misoprostol enabled greater dilatation in more women
Oppegaard and colleagues found greater mean cervical dilatation with misoprostol in premenopausal women than with placebo (6.4±2.4 mm, compared with 4.8±2.2 mm), more women achieving at least 5-mm cervical dilatation (88% versus 65%), and fewer women being difficult to dilate for hysteroscopy (20% versus 32%). As in previous studies, they also found misoprostol to be an ineffective cervical-ripening agent in postmenopausal women.
Strengths of this study
Because this study was randomized and placebo-controlled, bias in the evaluation of outcomes was minimized. The sample size was based on a sequential trial design, which ensures adequate power to answer the question of interest using as few women as possible.
The medication was self-administered and therefore more convenient than physician administration. In addition, women were questioned afterward to determine the acceptability of the self-administered medication, and 83% of premenopausal subjects found self-administration fairly or completely acceptable.
Oppegaard and colleagues recommend that 1,000 μg of vaginal misoprostol be offered to nulliparous premenopausal women before operative hysteroscopy, but they do not present data specific to nulliparous women.
Moreover, the use of 1,000 μg of misoprostol is higher than in most previous studies, and Oppegaard and colleagues do not compare different dosages. The use of a higher dosage (1,000 μg) may be expected to cause more side effects. Indeed, researchers found a higher incidence of vaginal bleeding with misoprostol, compared with placebo (21% versus 3%), and 42% of women receiving misoprostol experienced mild or moderate abdominal pain, with 7% reporting severe abdominal pain.
WHAT THIS EVIDENCE MEANS FOR CLINICAL PRACTICE
The use of self-administered vaginal misoprostol 12 hours before operative hysteroscopy in premenopausal women increases cervical dilatation and reduces the difficulty of dilatation. Oppegaard and colleagues used 1,000 μg of misoprostol, although earlier studies suggested benefit with 200 μg to 400 μg.
Although the route and timing of misoprostol for cervical ripening before hysteroscopy appears evident from the literature (vaginal administration 12 hours before the procedure), the ideal dosage is still unclear. Furthermore, misoprostol carries potential side effects, including vaginal bleeding and abdominal pain.—JOAN M.G. CRANE, MD, MSC
1. Crane JM, Healey S. Use of misoprostol before hysteroscopy: a systematic review. J Obstet Gynaecol Can. 2006;28:373-379.
2. Alfirevic Z, Weeks A. Oral misoprostol for induction of labour. Cochrane Database Syst Rev. 2006;(2):CD001338.-
3. Hofmeyr G, Gülmezoglu A. Vaginal misoprostol for cervical ripening and induction of labour. Cochrane Database Syst Rev. 2003;(1):CD000941.-
4. Barcaite E, Bartusevicius A, Railaite DR, Nadisauskiene R. Vaginal misoprostol for cervical priming before hysteroscopy in perimenopausal and postmenopausal women. Int J Gynaecol Obstet. 2005;91:141-145.
5. Darwish AM, Ahmad AM, Mohammad AM. Cervical priming prior to operative hysteroscopy: a randomized comparison of laminaria versus misoprostol. Hum Reprod. 2004;19:2391-2394.
6. Preutthipan S, Herabutya Y. A randomized comparison of vaginal misoprostol and dinoprostone for cervical priming in nulliparous women before operative hysteroscopy. Fertil Steril. 2006;86:990-994.