OC20.06: Serial cervical‐length in uncomplicated triplets as a screening for spontaneous preterm birth <32 weeks

To describe the performance of serial CL measurements as a predictor of spontaneous preterm birth (sPTB) < 32 weeks gestation in “uncomplicated” triplet pregnancies. Retrospective chart review of triplets followed in a single University Hospital in Argentina from 2011 to 2024. Inclusioncriteria were triplets with ≥ 2 CL measurement between 18 and 29 +6 weeks with available data of the delivery. Exclusion criteria included iatrogenic delivery <32 weeks, cerclage, fetal death, structural anomalies, polyhydramnios, Twin–twin transfusion syndrome (TTTS), TAPS, and TRAP. The screening was considered positive if any CL measurement was <25 mm. We report sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), positive and negative LR and area under the ROC curve (AUC). Among 90 triplets followed in our unit during the study period, 46 were excluded due to pregnancy complications or incomplete follow-up. We included 44 patients: 23 (52.3%) were trichorionic, 16 (36.4%) dichorionic triamniotic and 5 (11.3%) monochorionic triamniotic. During the follow-up, 13/44 patients (29.5%) had a short cervix and delivered at a mean gestational age of 30.0 + 2.9 weeks, while the remaining 31/44 patients (70.5%) had a CL>25mm and delivered at 33.5 + 1.27 weeks (p < 0.00001). The performance of serial CL measurements showed a sensitivity 88.9% (95% CI, 51.8-99.7), a specificity 85.7% (95% CI, 69.7-95.2), PPV 61.5% (95% CI, 31.6-86.1), NPV 96.8% (95% CI, 83.3-99.9), LR+ 6.22 (95% CI, 2.68-14.47), a LR- 0.13 (95% CI, 0.02-0.83) and AUC 0.87 (95% CI, 0.75-1.00). In this limited series, the performance of serial CL measurements in uncomplicated triplets showed a good performance. More studies are needed to establish the real value of this strategy and to define if it has a role in clinical practice.