Objective: To observe the effect of the combination of fluid-increasing decoction, low molecular heparin sodium and aspirin in the treatment of oligohydramnios in pregnancy. Methods: In this study, 114 pregnant women with oligohydramnios during pregnancy admitted to our hospital between May 2019 and March 2022 were selected as objects, and the pregnant women were equally divided into the observation group and the experimental group by random number table method, with 57 cases in each group. The observation group received conventional fluid infusion, low molecular heparin sodium and aspirin, while the experimental group was treated with fluid-increasing decoction on the basis of the observation group. The treatment effect, S/D level, amniotic fluid index, maximum vertical pocket (MVP), coagulation indexes (plasma prothrombin time (PT), plasma activated partial thromboplastin time (APTT), fibrinogen (FIB)), pregnancy outcome and adverse reactions were compared between the two groups. Results: The total effective rate of treatment was obviously better in the experimental group than that in the observation group (P<0.05); the S/D level after treatment in the experimental group was remarkably lower than that in the observation group (P<0.05). The amniotic fluid index and MVP were remarkably higher in the experimental group than in the observation group after treatment (P < 0.05). No significant differences in PT, APTT and FIB were found between the two groups before and after treatment (P > 0.05). The rate of oligohydramnios at delivery, cesarean section rate, neonatal weight status and preterm delivery rate were dramatically better in the experimental group than in the observation group (P < 0.05). Post-partum haemorrhage rate, neonatal asphyxia rate, amniotic fluid contamination rate and incidence of adverse events were not significantly different between the two groups of pregnant women (P > 0.05). Conclusion: The combination of fluid-increasing decoction, low molecular heparin sodium and aspirin is clinically effective and safe in the treatment of pregnant women with oligohydramnios during pregnancy. The combination is effective in reducing the S/D ratio of fetal umbilical blood flow, enhancing the amniotic fluid index and MVP in pregnant women with oligohydramnios during pregnancy, whilst not adversely influencing the coagulation function of the mother, thus contributing to a reduction in the risk of adverse pregnancy outcomes.