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Prematurity

Poster Session 2

(530) Comparison of the normal mid-trimester cervical length between singleton and twin gestations.

Tuesday, February 13, 2024
3:30 PM – 5:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Foundation Awardee
Objective:

Limited information exists in the literature establishing a normal cervical length (CL) among asymptomatic twin pregnancies in the mid-trimester. It is unclear if the same standard normal values should be used in twins as is used for singletons. We aim to compare these two populations.


Study Design:

This is a retrospective cohort study at an academic medical center reviewing all pregnancies over a 5-year period where mid-trimester transvaginal CL data between 15-28 weeks were available among asymptomatic twin gestations. All CLs were performed by Registered Diagnostic Medical Sonographers at a single site. Previous literature has described the mean mid-trimester CL among singleton gestations to be 39.2±6.0mm, with the 10th percentile between 16-22 weeks and 22-24 weeks in singleton gestations described as less than 30mm and 25mm, respectively. In our twin cohort, the mean CL between 19 weeks through 20 weeks and 6 days, as well as the 10th percentile at 16-22 weeks and 22-24 weeks was calculated. Following a D’Agostino-Pearson normality test, these values were compared to the corresponding values in singletons using paired t-tests. Subgroup analyses were performed for those who delivered preterm and term and compared to all-comers above using ANOVA.


Results:

179 twin gestations with at least one documented mid-trimester CL were analyzed. The mean CL among asymptomatic twin gestations between 19 weeks through 20 weeks and 6 days was 40.1±0.8mm, compared to the mean of 39.2±6.0mm among singletons (p< 0.001). There was no difference among those who delivered term and preterm, with values of 40.2±0.8mm and 40.1±0.8mm, respectively (p=0.999). The 10th percentile CL at 16 weeks through 21 weeks and 6 days and 22 weeks through 23 weeks and 6 days among asymptomatic twins was 32mm (n=275) and 25mm (n=193), respectively.


Conclusion:

The thresholds for a normal mid-trimester CL among asymptomatic patients is similar between singleton and twin gestations.