This study aimed to assess the performance of a previously published algorithm for the first-trimester prediction of spontaneous PTB in a cohort of Brazilian women.

This was a retrospective cohort study of women undergoing routine antenatal care. Researchers obtained maternal characteristics and medical history. Researchers inserted the data in the FMF online calculator to estimate the individual risk of PTB.

In total, researchers included 1,323 women. Of those, 23 had a spontaneous PTB before 34 weeks of gestation, 87 had a preterm birth between 34 and 37 weeks, and 1,197  had a term delivery. Smoking and history of spontaneous PTB remained significantly associated with spontaneous PTB in the multivariate logistic regression analysis. The FMF algorithm provided significant PTB prediction <34 weeks of gestation, but the detection rates for fixed false-positive rates of 10% and 20% were low.

Maternal characteristics and history in the first trimester can significantly predict spontaneous delivery before 34 weeks of gestation. Although the predictive algorithm performed similarly to previously published data, the detection rates are low, and research on new biomarkers to improve its performance is needed.