Association of open fetal MMC repair post-operative cervical length and gestational age at delivery

To determine whether post-operative cervical length is associated with duration of pregnancy following prenatal myelomeningocele repair. This was an IRB approved retrospective cohort study. We analyzed the immediate and post-operative day one cervical length independently as well as the change in cervical length between time points. The presence or absence of a prominent echolucency along the length of the endocervical canal on post-operative ultrasound was also assessed as a potential marker for prematurity (Image). We developed linear regression models to examine the associations between variables of interest and gestational age at delivery. After excluding 12 patients for inadequate transvaginal ultrasound imaging to asses cervical length, a total of 65 patients were available for analysis. For this cohort the mean (sd) and median (IQR) gestational age at delivery was 32.1 weeks (3.3 weeks) and 32.4 weeks (29.9-34.4 weeks). Mean (sd) and median (IQR) cervical length immediately post-operative was 4.13 cm (0.6 cm) and 4.2 cm (3.6 cm-4.5 cm) respectively and for post-operative day one 4.23 cm (0.6 cm) and 4.2 cm (3.8 cm-4.7 cm) respectively. For every increase of 1 cm above 3.63 cm on the immediate post-operative measurement, gestational age at delivery increased by 2.2 weeks (p=0.0008). A similar observation was noted on post-operative day one measurements (Figures). Out of 65 patients, 14 (22%) demonstrated endocervical canal echolucency. Compared to patients who did not have this finding, endocervical canal echolucency was associated with a reduction in gestational age at delivery by 2.4 weeks (30.1 weeks vs 32.6 weeks) (p=0.01). No association was found between interval change in cervical length and gestational age at delivery. For prenatal myelomeningiocele repair both immediate post-operative and post-operative day one transvaginal cervical length are significantly associated with gestational age at delivery. The finding of post-operative endocervical canal echolucency is a marker for increased risk for premature delivery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)