(257) Aspirated and computed cervical stiffness throughout gestation for patients with and without a pessary

Short cervical length is a risk factor for spontaneous preterm birth (sPTB). This study measured cervical stiffness in patients with a short cervix as an additional assessment to estimate sPTB risk. We also compared the change in cervical stiffness throughout pregnancy for patients with a short cervix with and without a pessary. Lastly, we compared cervical stiffness between patients who delivered preterm versus term.

Study Design:

Single-site ancillary study to a randomized-controlled trial of usual care versus pessary placement among patients with a singleton gestation and a short cervix (≤2 cm). Aspirated cervical stiffness (aCS) was measured at baseline visit 1 (16w-23w6d) using the Pregnolia aspiration device and again at visit 2 (26-30w0d). At both visits, the cervical shape was obtained using transvaginal ultrasound. Computer-aided design and finite element analysis software combined these measurements with aCS to generate computed CS (cCS). Welch’s t-tests compared the baseline aCS and cCS and the difference in visit 2 and baseline aCS and cCS between patients in each treatment group. Lastly, aCS and cCS were compared between patients who delivered term or preterm, regardless of treatment.

Results:

At baseline, there was no difference in aCS between patients randomized to pessary (n=17) or usual care (n=16) (aCS=78mbar ± 40 vs 76mbar ± 39, p >0.05). At visit 2, patients randomized to pessary (n=10) had an increase in aCS and cCS compared to baseline value, while the patients randomized to usual care (n=8) had a decrease. However, this result was not statistically significant (aCS=7mbar ± 40 vs -18mbar ± 28 p >0.05; cCS=8kPa ± 67 vs -13kPa ± 23, p >0.05). Regardless of the treatment group, patients who delivered before 37 weeks (n=17) had lower cCS than those who delivered at term (n=18) (cCS =18kPa ± 16 vs 38kPa ± 33, p< 0.05).

Conclusion:

There was no significant difference in cervical stiffness between patients who received a pessary and those who did not. When not accounting for the treatment arms, patients with lower cervical stiffness delivered preterm.