Objective:To analyze the predictive value of six hormonal changes in pregnant women with scarred uterus for the occurrence of oligohydramnios in their second pregnancy.Methods:A retrospective study was conducted to select the clinical data of 54 pregnant women with hypohydramnios in scarred uterus who were admitted to the First People’s Hospital of Suzhou from May. 2021 to Mar. 2023. They were included in the oligohydramnios group, and another 54 patients with normal amniotic fluid in scar uterus re-pregnancy during the same period were selected and included in the normal amniotic fluid group. Both groups of postpartum women underwent six hormone tests, including follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E 2), progesterone (P), testosterone (T), and prolactin (PRL). Two sets of baseline data were collected and binary logistic analysis was used to investigate the relationship between six hormones and oligohydramnios in women with scarred uterus during re-pregnancy. Receiver operating characteristic curve (ROC) was adopted to evaluate the six hormonal factors in predicting oligohydramnios in pregnant women with scar uterus during re pregnancy. The restricted cubic spline method combining spline function and logistic regression were used to analyze the dose-response relationship between six hormones and oligohydramnios in scar pregnant women during re-pregnancy. Results:The proportion of multiple pregnant women in the oligoamnios group [20.37% (11/54) ] was higher than that in the normal amniotic fluid group [5.56% (3/54) ] ( P < 0.05). The levels of FSH, E 2, P and PRL in oligohydramnios group were lower than those in normal amniotic fluid group [ (8.11±1.83) IU/L, (125.61±61.43) p /L, (16.33±3.15) mmol /L, (315.15±87.63) mIU/L],[ (9.87±2.05) IU/L, (148.52±50.57) pg/L, (20.14±4.07) mmol/L, (366.18±99.36) mIU/L] ( P<0.05) ; The levels of LH and T in oligohydramnios group [ (18.65±7.16) IU/L, (1.75±0.19) mmol/L] were compared with those in normal amniotic fluid group [ (20.67±8.53) IU/L, (1.73±0.11) mmol/L] and there was no significant difference between the two groups ( P<0.05). The results of binary logistic regression analysis showed that multiple pregnancy ( OR=11.507, 95% CI: 2.174-60.902, P=0.004) was a risk factor for recurrent oligohydramnios in women with scarred uterus. The high expression of FSH ( OR=0. 620, 95% CI: 0.224-0.845, P=0.001), E 2 ( OR=0.988, 95% CI: 0.978-0.998, P=0.021), and P ( OR=0.750, 95% CI: 0.645-0.873, P<0.001) was a protective factor for oligohydramnios in pregnant women with scar uterus during re-pregnancy. The ROC curve was plotted, and the results showed that AUC of FSH, P, and combined detection for predicting oligohydramnios in pregnant women with scarred uterus during re-pregnancy were 0.754, 0.768, and 0.870, respectively. The correlation between serum levels of FSH, E 2, and P and the occurrence of oligohydramnios in pregnant women with scarred uterus during re-pregnancy showed a linear dose-response relationship ( P<0.05). The levels of serum FSH, E 2, and P were negatively correlated with the occurrence of oligohydramnios in pregnant women with scar uterus. Especially when FSH<9.255 IU/L, E 2<158.465 pg/L, P<19.000 mmol/L, the occurrence of oligohydramnios in pregnant women with scar uterus increased with the decrease of FSH, E 2, and P levels. Conclusion:The six hormonal changes in pregnant women with scar uterus are closely related to the occurrence of oligohydramnios during re-pregnancy, and can effectively predict the risk of oligohydramnios during re-pregnancy.