Cerclage for the short cervix demonstrated by transvaginal ultrasound: current practice and opinion

(1) To elucidate the views of obstetricians with respect to the use of transvaginal ultrasound in general, and, specifically, for determining cervical length, and the conditions under which obstetricians would employ cervical cerclage based on a sonographically revealed shortened cervix; and (2) to determine the possibility of a randomized controlled trial on the use of cervical cerclage in this situation.

A 7-item questionnaire in French and English was designed and pretested. Questionnaires were mailed to 1421 physicians identified in the Canadian Medical Directory as practising obstetricians/gynaecologists in Canada. Returned questionnaires were scanned into an Access database for simple descriptive analyses.

Responses were received from 766 physicians. Of these 766 respondents, 604 physicians indicated they continued to practise obstetrics and supplied information that was usable in the analysis. The majority of the 604 respondents (85.6%) reported that they would recommend transvaginal ultrasound only in pregnant women with 1 or more risk factors for preterm birth. Respondents were most likely to recommend a cerclage, and least unsure of their decision to do so, if the gestational age was less than 23 weeks, the cervical length was less than 1 cm, and additional risk factors for preterm birth were present. As gestational age and cervical length increased, respondents were less likely to recommend cerclage and more unsure of their decision to do so. The pattern of responses was similar for singleton and multiple pregnancies. The McDonald technique was favoured over the Shirodkar technique by 70.4% of the respondents who performed cervical cerclage procedures. Adjunctive antibiotics were used with cerclage by 52.5% and adjunctive tocolytics were employed by 37.4%. The majority (68.8%) of the respondents who performed cervical cerclage procedures stated that they would participate in a randomized controlled trial on the effectiveness of cerclage for a sonographically revealed short cervix.

In the case of a short cervix determined by ultrasound, there is significant uncertainty surrounding the decision whether to place a cerclage and considerable variation in the clinical practice on its placement. In the absence of good evidence to guide clinical practice, a randomized controlled trial is being planned.