重复药物流产小鼠后续妊娠生育结局的研究

Study of subsequent pregnancy outcomes after repeated medical abortion in mice

目的研究重复药物流产对小鼠后续妊娠过程和生育结局的影响。方法BALB／c小鼠用米非司酮（RU486）药物重复（2次）药物流产后再连续妊娠／生育3次动物为实验组，以正常自然妊娠／生育4次动物为对照组。结果与对照组比较，重复流产后的累积妊娠率在第12个交配周期以上未受到明显影响，但是，在第4～10个交配周期显著降低（P〈0．01）；第3胎的平均产仔数显著降低（P〈0．05）；实验组随着胎次的增加，仔鼠体质量在相同产次雄性均高于雌性，两组间比较雌性仔鼠接近（P〉O．05），而在雄性仔鼠实验组低于对照组，其中第2胎和第3胎显著降低（均P〈O．05）。结论在重复药物流产的后续妊娠过程中小鼠生育力降低，随着胎次增加产仔率显著下降。

Objective： To study the effect of repeated medical abortion on the outcome of subsequent pregnancies in mice. Methods： A model of mifepristone （RU486）-induced medical abortion in BALB/c mice was used. The mice with repeated （twice） medical abortions and subsequent three times of pregnancy/childbirth were used as study group, and the mice with four times of normal nature pregnancies as control group. Results： Compared with control group,the cumulative pregnancy rate after repeated medical abortion was not different beyond 12 mating cycles, but it was significantly decreased in the 4-12 mating cycles （P〈 0.05）. The average litter size significantly decreased in the third parity （P〈0.05）. With increasing parity, the body mass of male newborn was higher than female newborn in the same parity. A comparative study of body mass showed no obvious difference in female newborn between the two groups （P〉0.05） ,but it was significantly lower in male newborn of study group than that in the control group, especially in the second and third parity （P〈0.05）. Conclusions： The fertility was significantly decreased in the mice with repeated medical abortion and subsequent pregnancy/childbirth. With increasing parity, the litter size significantly decreased.