Abstract: Objective To analyze the efficacy of aspirin combined with low molecular weight heparin calcium in the treatment of fetal growth restriction and its impact on umbilical artery blood flow parameters and delivery outcomes, in order to improve fetal intrauterine restriction and maternal and fetal delivery outcomes. Methods 70 pregnant women with fetal growth restriction admitted to Youyang Hospital of Chongqing Youyang County People's Hospital (starting from May 2020 to May 2021) were selected for this clinical practice study. The patients were divided into groups using a single and double number method, with 35 cases per group.The treatment drug in the study group was aspirin combined with low molecular weight heparin calcium, while the control group was low molecular weight heparin calcium. The comparison was made before and after treatment The levels of umbilical artery blood flow parameters including pulsatile index (PI), resistance index (RI), peak systolic/diastolic(S/D), developmental indicators such as head circumference, femoral length, body weight, biparietal diameter, total effective rate of treatment, and incidence of adverse maternal and fetal delivery outcomes) in the last two groups of fetuses. Results After treatment, the levels of fetal umbilical artery blood flow parameters (including PI, RI, S/D) in the study group were significantly lower than those in the control group. The levels of developmental indicators such as fetal head circumference, abdominal circumference, femoral length, and femoral length in the study group were significantly higher than those in the control group. The total effective rate of treatment in the study group was significantly higher than that in the control group, and the incidence of adverse delivery outcomes in the study group was significantly lower than that in the control group. The comparison between the two groups was statistically significant (P<0.05). Conclusion The use of aspirin combined with low molecular weight heparin calcium in the treatment of fetal growth restriction can achieve good therapeutic effects. It can not only effectively improve fetal umbilical artery blood flow parameters and promote good fetal growth and development, but also reduce the incidence of adverse delivery outcomes for mothers and infants, there by improving the prognosis of mothers and infants. It is worth clinical application and promotion.

Key words: aspirin, low molecular weight heparin calcium, fetal growth restriction, umbilical artery blood flow parameters, delivery outcome