Centile charts of cervical elastography (E-Cervix™) parameters in asymptomatic twin pregnancies in the midtrimester

Objective: To describe the distribution of E-Cervix™ cervical elastography parameters and to construct centile charts in twin pregnancies during the midtrimester, and to explore their association with preterm birth (PB). Methods: This retrospective observational study included 52 asymptomatic dichorionic diamniotic twin pregnancies undergoing transvaginal ultrasound assessment during the midtrimester. Cervical length (CL) and cervical elastography parameters, including hardness ratio (HR), internal os strain (IOS), external os strain (EOS), and elasticity contrast index (ECI) were recorded. Empirical centile values were derived from observed data. PB rates < 37 weeks were evaluated using centile categories, and associations were explored using odds ratios with 95 % confidence intervals. Results: Overall, 23/52 women (44.2 %) delivered before 37 weeks of gestation. HR values at or below the 10th percentile had a higher rate of PB (100.0 % vs 35.0 %; odds ratio 23.76, 95 % CI 1.25 to 452.52, p = 0.004). Similarly, IOS values at or above the 90th percentile showed increased risk of PB (100.0 % vs 37.8 %; odds ratio 21.07, 95 % CI 1.10 to 402.55, p = 0.006), as were higher EOS values (odds ratio 7.95, 95 % CI 1.42 to 44.60, p = 0.019). ECI was higher in women who delivered preterm compared with those delivering ≥ 37 weeks (4.17 vs 3.40, p = 0.029), whereas CL did not differ between groups. Conclusion: Midtrimester cervical elastography parameters show wide variability and can be described using empirical centile charts. Extreme elastographic values, particularly low HR and high strain measurements, were associated with PB, suggesting that cervical elastography may provide complementary information to conventional cervical length assessment.