Development and Internal Validation of Prediction Model on Delivery within 7 Days for Spontaneous Late Preterm Labor: A Retrospective Cohort Study

Main Article Content

Rapeepat Noknu
Sorawat Sangkeaw
Khodeeyoh Kasoh
Sunittha Sanguanchua

Abstract

Objective: To develop and internally validate a predictive model for estimating the likelihood of delivery within 7 days of the onset of spontaneous late preterm labor.


Methods: We conducted a retrospective cohort study involving singleton pregnancies with late preterm labor (gestational age 34-36+6 weeks) from October 1, 2018, to September 30, 2023. Predictors were selected based on expert consensus and stepwise backward elimination. The model was developed using multivariable logistic regression, with performance assessed through calibration (slope and plot), discrimination (AUROC), and overall prediction (Brier score). Internal validation was performed using 10-fold cross-validation.


Results: The study included 371 pregnancies: 254 delivered within 7 days and 117 later. The optimal model, based on the selected performance metrics, was the multivariable logistic regression model. It demonstrated robust discrimination and overall predictive accuracy, with an AUROC of 0.860 (95% CI, 0.756 to 0.942) and a Brier score of 0.144 (95% CI, 0.100 to 0.206). Calibration metrics included a calibration-in-the-large of -0.002 (95% CI, -0.076 to 0.063) and a calibration slope of 6.102 (95% CI, 2.596 to 12.208). Key predictors identified by the model were maternal age, gestational age at labor onset, coexisting infections, hypertension, cervical dilation, cervical effacement, uterine contractions, nulliparity, and coexisting diabetes


Conclusion: The model accurately predicts delivery within 7 days of spontaneous late preterm labor, demonstrating high predictive performance in the studied cohort. This supports clinical decision-making and potentially optimizes the timely use of dexamethasone interventions.

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Noknu, R.; Sangkeaw, S. .; Kasoh, K. .; Sanguanchua, S. Development and Internal Validation of Prediction Model on Delivery within 7 Days for Spontaneous Late Preterm Labor: A Retrospective Cohort Study. Thai J Obstet Gynaecol 2025.
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References

American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins-Obstetrics. Practice Bulletin no. 171: Management of preterm labor. Obstet Gynecol 2016 Oct;128(4):155-164.

Royal Thai College of Obstetricians and Gynaecologists. Management of Preterm Labor and Preterm Prelabor Rupture of Membranes. RTCOG Clinical Practice Guideline. OB 66-033. RTCOG 2023:9-36.

Cunningham FG, Leveno KJ, Dashe JS, Hoffman BL, Spong CY, Casey BM. Williams Obstetrics. 26th ed. New York: McGraw-Hill, 2022:615-623.

American College of Obstetricians and Gynecologists. Committee opinion No. 713: antenatal corticosteroid therapy for fetal maturation. Obstet Gynecol 2017;130(2):102-109.

Gyamfi-Bannerman C, Thom EA, Blackwell SC, Tita ATN, Reddy UM, Saade GR, et al. Antenatal betamethasone for women at risk for late preterm delivery. N Engl J Med 2016;374(14):1311-1320.

Roberts D, Brown J, Medley N, Dalziel S. Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth. Cochrane Database Syst Rev 2006;(3)

Hackney ND, Olson-Chen C, Thornburg LL. What do we know about the natural outcomes of preterm labor? A systematic review and meta-analysis of women without tocolysis in preterm labor. Paediatr Perinat Epidemiol 2013;27(5):452-460.

Humbeck C, Jonassen S, Bringewatt A, Pervan M, Rody A, Bossung V. Timing of antenatal steroid administration for imminent preterm birth: results of a prospective observational study in Germany. Arch Gynecol Obstet 2023;308(3):839-847.

Ninan K, Liyanage SK, Murphy KE, Asztalos EV, McDonald SD. Evaluation of long-term outcomes associated with preterm exposure to antenatal corticosteroids: a systematic review and meta-analysis. JAMA Pediatr 2022;176(6)

McKinzie A, Yang Z, Teal E, Daggy JK, Tepper RS, Quinney SK, et al. Are newborn outcomes different for term babies who were exposed to antenatal corticosteroids? Am J Obstet Gynecol 2021;225(5):536.e1-536.e7.

Räikkönen K, Gissler M, Kajantie E. Associations between maternal antenatal corticosteroid treatment and mental and behavioral disorders in children. JAMA 2020;323(19):1924-1933.

Stock SJ, Horne M, Bruijn M, White H, Heggie R, Wotherspoon L, et al. A prognostic model, including quantitative fetal fibronectin, to predict preterm labor: the QUIDS meta-analysis and prospective cohort study. Health Technol Assess 2021;25(52):1-186.

Glover AV, Battarbee AN, Gyamfi-Bannerman C, Boggess KA, Sandoval G, Blackwell SC, et al. Association between features of spontaneous late preterm labor and late preterm birth. Am J Perinatol 2020;37(4):357-364.

Wong TTC, Yong X, Tung JSZ, Lee BJY, Chan JMX, Du R, et al. Prediction of labor onset in women who present with symptoms of preterm labor using cervical length. BMC Pregnancy Childbirth 2021;21(1):359.

Leow SM, Di Quinzio MKW, Ng ZL, Grant C, Amitay T, Wei Y, et al. Preterm birth prediction in asymptomatic women at mid-gestation using a panel of novel protein biomarkers: the Prediction of PreTerm Labor (PPeTaL) study. Am J Obstet Gynecol MFM 2020;2(3):1-16.

Stock SJ, Horne M, Bruijn M, White H, Boyd KA, Heggie R, et al. Development and validation of a risk prediction model of preterm birth for women with preterm labour symptoms (the QUIDS study): A prospective cohort study and individual participant data meta-analysis. PLOS Med 2021;18:e1003686.

Riley RD, Ensor J, Snell KIE, Harrell FE, Martin GP, Reitsma JB, et al. Calculating the sample size required for developing a clinical prediction model. BMJ 2020;368:m441.

Van Calster B, McLernon DJ, Van Smeden M, Wynants L, Steyerberg EW, on behalf of Topic Group ‘Evaluating diagnostic tests and prediction models’ of the STRATOS initiative. Calibration: the Achilles heel of predictive analytics. BMC Med 2019;17:230.