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

Abstract

Background: To establish that magnetic resonance imaging (MRI) can provide an objective measurement of the biophysical state of the cervix and to measure the response of the cervix to prostaglandins in the first trimester of pregnancy. Methods: A comparative study, with each patient serving as her own control, was carried out on 10 primigravid women with 49-84 days amenorrhoea undergoing surgical termination of pregnancy. Each woman had two MRI scans of the uterus and cervix. The first scan was performed prior to administration of prostaglandins and the second scan 2.5-3 h following an 800 μg dose of misoprostol given vaginally. Cervical change was assessed by measurement of cervical length, transverse diameter of the cervix, diameter of the internal os and cervical stromal signal intensity. Results: A significant 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 administration of misoprostol. In five women a significant change in one or both components of the cervical stromal signal was detectable and in five women no change could be demonstrated. Conclusion: MRI is capable of detecting changes in the physical parameters of the cervix following administration of prostaglandin. However, the changes detected in the stromal signal intensity are less consistent. The potential of MRI as a clinical tool to monitor cervical changes in a variety of clinical situations warrants further investigation.