Risk Score Predicting Spontaneous Preterm Delivery within 7 Days After Preterm Labor
Nattha Hatsabodesonton¹, Monyada Pleankong¹, Sinart Prommas¹, Buppa Smanchat¹, Kornkarn Bhamarapravatana², Komsun Suwannarurk³
Affiliation : ¹ Department of Obstetrics and Gynecology, Bhumibol Adulyadej Hospital, Royal Thai Air Force, Bangkok, Thailand; ² Department of Preclinical Sciences, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand; ³ Department of Obstetrics and Gynecology, Faculty of Medicine, Thammasat University, Pathum Thani, Thailand
Objective: To investigate risk factors of preterm labor (PTL) as a predictor model for preterm delivery (PTD) within seven days.
Materials and Methods: The present study was a historical cohort study conducted at Bhumibol Adulyadej Hospital, Thailand between January 2018 and December 2023. Participants were singleton pregnant women who attended antenatal care and were diagnosed with PTL with a gestational age (GA) between the 24⁺⁰ and the 36⁺⁶ weeks. Participants that delivered within and outside the seven-day mark were divided into the study and control groups. Risk factors, namely maternal age, education level, family’s income, parity, history of PTD, GA at PTL, pre-pregnancy body mass index (PPBMI), nifedipine usage, preterm pre-labor rupture of membrane (PPROM), urinary tract infection (UTI), and vaginal bleeding were collected and analyzed to create predictive model of PTD within seven days (PD 7).
Results: One thousand fifty-five pregnant women were recruited. The mean age of participants was 28.8 years. Significant factors for PTD including advanced maternal age (AMA), PPBMI, nifedipine usage, multiparity, PPROM, treated UTI, vaginal bleeding and history of PTD were used to generate the predictive model for PD 7. PD 7 scores greater than 26 predicted delivery within seven days with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR)+ and LR– of 72.7%, 78.5%, 77.9%, 73.4%, 3.4, and 0.4, respectively.
Conclusion: AMA, higher GA, multiparity, PPROM, vaginal bleeding, treated UTI, and history of PTD were significant risk factors for PD 7. The PD 7 model demonstrated good predictive performance. The model can be applied as a clinical decision-support tool to guide appropriate corticosteroid administration and timely referral, reducing unnecessary interventions. Incorporation of the PD 7 model into antenatal care practice and hospital protocols may enhance perinatal outcomes and promote standardized management of PTL.
Received 9 June 2025 | Revised 10 October 2025 | Accepted 20 October 2025
DOI: 10.35755/jmedassocthai.2025.12.980-985-03155
Keywords : Prediction; Preterm; Delivery; Risk
