[Does post operative sonographic position of preventive cervical cerclage affect gestational age at birth?]

OBJECTIVE: To evaluate whether the position of preventive cerclage determined by immediate postoperative transvaginal cervical ultrasound is predictive of preterm birth.

METHODS: A single-center retrospective study conducted between 1 August 2007 and 31 December 2015 in a maternity type III who included women carrying out for a single pregnancy and who receive a McDonald preventive cerclage. Measurements of internal os-stitch, stitch-external os and the total length of the cervix were performed during immediate postoperative transvaginal cervical ultrasound. The position of the cerclage has been defined by the internal os-stitch/cervical length and stitch-external os/cervical length ratios. Measures were compared according to gestational age at delivery (before and after 32weeks and before and after 37weeks).

RESULTS: During the study period, 379 single pregnancies that received a McDonald preventive cerclage were included. The mean gestational age at delivery was 37.6±3.6 SA. The rate of preterm birth before 32weeks was 6.5% (n=25) and before 37weeks was 16.6% (n=63). There was no significant difference in the internal ost-stitch/cervical length ratios and the stitch-external ost/cervical length ratio between women who delivered before and after 32weeks or for those who delivered before and after 37weeks. The areas under the ROC curves for the various parameters studied were all less than or equal to 0.6.

CONCLUSIONS: The position of cerclage determined by transvaginal cervical ultrasound in immediate post operative does not seem predictive of the risk of premature birth.