Effects of leonurine hydrochloride on medically induced incomplete abortion in early pregnancy rats.

OBJECTIVES: To determine the effect of leonurine hydrochloride (LH) on abnormal bleeding induced by medical abortion.

STUDY DESIGN: Rats had incomplete abortions induced in early pregnancy using mifepristone in combination with misoprostol. After abortion, rats were treated with LH for 7 days, and the duration and volume of uterine bleeding were observed. Approximately 30min after the last treatment, the animals were killed and the uterine shape was observed. The sinistro-uteri were suspended in organ baths to record the contraction curves, including the frequency and tension for 10min; the dextro-uteri were fixed with formaldehyde for pathologic evaluation. In addition, blood samples were collected from the femoral artery for the measurement of estradiol (E₂) and progesterone (P) levels by radioimmunoassay.

RESULTS: In in vivo experiments, compared with the model group, LH treatment markedly reduced the volume of bleeding and intrauterine residual, and significantly shortened the duration of bleeding. From the contraction curve, LH notably reinforced the frequency and tension of uterine contractions. LH remarkably elevated the serum estradiol level in rats, but had no obvious effect on progesterone level.

CONCLUSIONS: LH has an inhibitory effect on bleeding caused by incomplete abortion; the mechanism may be related to up-regulation of the E₂ level, leading to an increase in uterine contractions and evacuation of intrauterine residuum.