Predicting sPTB remains a significant challenge in modern obstetrics. Moreover, a recent systematic review examined spontaneous preterm birth prediction models specifically for asymptomatic low-risk singleton pregnancies. Initially, researchers screened over 16,000 records to find eligible studies. Subsequently, they included three prospective cohort studies that met their strict criteria. Notably, these studies featured sample sizes ranging between 135 and 1,107 patients, with sPTB rates of 4.4% to 11.5%.

Furthermore, all models used logistic regression to determine risk. However, substantial heterogeneity existed across the study predictors and outcomes. Consequently, researchers summarized the findings narratively rather than through a meta-analysis. Specifically, one model combined uterocervical angle (UCA) ≥99° and cervical length (CL) ≤33.8 mm. Additionally, another approach utilized the UCA/CL ratio with a specific cutoff. Moreover, a third model integrated biochemical markers, such as glutamate-acetate-D-lactate, with fetal fibronectin and cervical length.

Current Evidence on Spontaneous Preterm Birth Prediction

Although some models achieved a high area under the curve (AUC), the overall quality of evidence was poor. Indeed, all included studies exhibited a high risk of bias, particularly in the analysis domain. Furthermore, none of the models underwent internal or external validation. Therefore, clinicians cannot yet apply these tools in daily practice. The review concludes that current evidence is insufficient to support routine clinical use in low-risk populations.

Thus, future research must focus on multicenter studies using standardized predictors. Similarly, transparent reporting is vital for improving the reliability of future tools. Finally, robust validation is essential before any clinical implementation occurs to ensure patient safety and effective management.

Frequently Asked Questions

Which predictors are commonly used in sPTB models?

Cervical length (CL) is a consistent predictor across most studies. Additionally, newer models incorporate the uterocervical angle (UCA), quantitative fetal fibronectin, and specific cervicovaginal fluid metabolites like glutamate and acetate.

Are these prediction models ready for clinical use in India?

No, current evidence is insufficient. Most existing models have a high risk of bias and lack external validation. Therefore, clinicians should rely on established national guidelines rather than these developmental models for low-risk pregnancies.

What did the review conclude about the quality of the studies?

The review found marked heterogeneity and high risk of bias across all included studies. Specifically, the lack of standardized reporting and validation protocols limits the comparability and clinical applicability of the findings.

Disclaimer: This content is for informational and educational purposes only and does not constitute medical advice. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

Hanumaiah G et al. Prediction models for spontaneous preterm birth in asymptomatic low-risk singleton pregnancies: a systematic review. J Matern Fetal Neonatal Med. 2026 Dec undefined. doi: 10.1080/14767058.2026.2646356. PMID: 41866245.

Huy NVQ et al. Uterocervical angle and cervical length measurements for spontaneous preterm birth prediction in low-risk singleton pregnant women: a prospective cohort study. Arch Gynecol Obstet. 2024 Sep;310(3):1445-1453. doi: 10.1007/s00404-024-07646-4.

Stafford IA et al. A combination of cervicovaginal fluid glutamate, acetate and D-lactate identified asymptomatic low-risk women destined to deliver preterm: a prospective cohort study. Sci Rep. 2022 Feb 28;12(1):3298. doi: 10.1038/s41598-022-07367-3.