ObjectiveTo investigate the effect of ritodrine combined with allylestrenol on the success rate of tocolytic therapy in pregnant women with late threatened preterm labor (TPL).MethodsClinical data of 80 pregnant women with late TPL treated in Baofeng County Maternal and Child Health Hospital from May 2022 to May 2025 were retrospectively analyzed. According to different treatment regimens, they were divided into a control group (ritodrine,n＝40) and a study group (ritodrine+allylestrenol,n＝40). The clinical efficacy, safety, and pregnancy-related hormones [estriol (E3), progesterone (P)] were compared between the two groups.ResultsCompared with the control group, the study group showed higher effective rates for uterine contraction inhibition≥2 days ≥7days, a higher tocolysis success rate (all P＜0.05), and a longer average pregnancy prolongation time (P＜0.05). There were no significantly differences in the incidences of maternal adverse reactions and fetal tachycardia, as well as Gesell developmental scale (GDS) scores at 6 months of age and the incidence of respiratory diseases within 6 months in neonates between the two groups (all P＞0.05). Compared with the control group, the study group showed lower E3 and higher P after 72 hours of treatment (all P＜0.05).ConclusionRitodrine combined with allylestrenol in the treatment of late TPL can improve the success rate of tocolysis and regulate pregnancy-related hormones, without increasing the risk of maternal adverse reactions or affecting the long-term development of neonates.