Abstract: Objectives To study the effects of dopamine and phenylephrine for treatment of hypotension during cesarean
section under combined spinal epidural anesthesia (CSEA) on the stereology of the placenta. Methods Forty puerperants
undergoing cesarean section under CSEA were randomly divided into dopamine group and phenylephrine group.
Ropivacaine (16 mg) was administered immediately after spinal anethesia. Blood pressure was maintained near the baseline by
adjusting the drug infusion rate. Fetal blood gas, Apgar score, and placental villus microvascular stereological changes were
observed during the operation. Results The microvascular density was significantly lower in dopamine group than in
phenylephrine group (P<0.05). Phenylephrine group showed significantly lower umbilical artery blood pH than dopamine
group (P<0.05). The Apgar score and blood pressure were comparable between the two groups (P>0.05). Compared to the
baseline, both of the two groups showed significantly lowered heart rate during the operation (P<0.01). Conclusion Dopamine
is associated with the risk of fetal acidosis. Phenylephrine is helpful for preventing hypotension by increasing placental blood
flow and improving oxygen supply to ensure maternal and fetal safety during cesarean section.