TOPLINE:

In twin pregnancies, cervical length (CL) assessment during the first trimester might be useful in predicting the risk for spontaneous preterm birth before 34 weeks of gestation; CL measurements below 35 and 30 mm warranted closer follow-up. However, a history of preterm birth remained the strongest independent predictor.

METHODOLOGY:

• Researchers conducted a retrospective multicentre cohort study with a case-control analysis in Poland from 2015 to 2023 to determine whether the CL measurement during the first trimester independently contributes to the prediction of spontaneous preterm birth before 34 weeks of gestation in twin pregnancies.
• They evaluated 2004 women with twin pregnancies (1590 dichorionic and 414 monochorionic) who had two live foetuses at the time of scan at 11-13 weeks of gestation without any major abnormalities.
• Participants were divided into two groups on the basis of timings of delivery: those who delivered at 24 + 0 to 33 + 6 weeks of gestation and those who delivered after 34 weeks of gestation.
• CL measurements were performed using transvaginal ultrasonography according to International Society of Ultrasound in Obstetrics and Gynecology guidelines; CL cutoffs of 30 and 35 mm were evaluated.

TAKEAWAY:

• Spontaneous preterm birth before 34 weeks of gestation was reported in 226 twin pregnancies (11.3%). Women who delivered at 24 + 0 to 33 + 6 weeks of gestation had a higher prevalence of CL measurement below 35 mm (49.6% vs 22.3%) and below 30 mm (16.4% vs 3.9%; P < .001 for both) during the first trimester than those who delivered after 34 weeks of gestation.
• Before 34 weeks of gestation, CL measurements below 35 and 30 mm during the first trimester were associated with approximately 3.4-fold and 4.9-fold higher odds of spontaneous preterm birth, respectively (P < .05 for both).
• Maternal risk factors such as a history of preterm birth and type 1 or 2 diabetes were associated with approximately 19‑fold and 3.5‑fold higher odds of spontaneous preterm birth, respectively (P < .05 for both).
• After multivariable adjustment, a history of preterm birth was the only independent predictor of spontaneous preterm birth before 34 weeks of gestation.

IN PRACTICE:

"The assessment of CL in the first trimester helps to distinguish the group of twins which need a close follow up," the authors wrote.

SOURCE:

This study was led by Magdalena Litwińska, 1st Department of Obstetrics and Gynaecology, Medical University of Warsaw, Warsaw, Poland. It was published online on December 12, 2025, in BMC Pregnancy and Childbirth.

LIMITATIONS:

The study was retrospective and had incomplete data on maternal characteristics. Interobserver variability was not assessed despite measurements being performed by operators at five different centres. CL measurements were performed within a 2-week timeframe and not adjusted for gestational age.

DISCLOSURES:

This study did not receive any external funding. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.