Magnetic resonance imaging of the human cervix: a study of the effects of prostaglandins in the first trimester

BACKGROUND: To establish that magnetic resonance imaging (MRI) ean provide an objective measurement of the biophysical state of the cervix and to meas ure the response of the cervix to prostaglandins in the first trimester of pregnancy. METHODS: A comparative study, with each patient serving as her o wn control, was carried out on 10 primigravid women with 49-84 days amenorr hoea undergoing surgical termination of pregnancy. Each woman had two MRI s cans of the uterus and cervix. The first scan was performed prior to admini stration of prostaglandins and the second scan 2.5-3 h following an 800 mug dose of misoprostol given vaginally. Cervical change was assessed by measu rement of cervical length, transverse diameter of the cervix, diameter of t he internal os and cervical stromal signal intensity. RESULTS: A significan t difference in cervical length (P = 0.012), transverse diameter (P = 0.001 ) and diameter of the internal os (P = 0.008) was detected following the ad ministration of misoprostol. In five women a significant change in one or b oth components of the cervical stromal signal was detectable and in five wo men no change could be demonstrated. CONCLUSION: MRI is capable of detectin g changes in the physical parameters of the cervix following administration of prostaglandin. However, the changes detected in the stroma] signal inte nsity are less consistent. The potential of MRI as a clinical tool to monit or cervical changes in a variety of clinical situations warrants further in vestigation.