The effect of impairment of blood supply to the rat uterus.

Over the last decades much attention has been directed to establishing the cause of altered fetal growth and habitual abortion. Great emphasis has been placed on placental blood flow, but relatively few studies have been published on the effect of impaired uterine blood supply. This study examined the effect of impaired uterine blood flow using the white rat, with its bilateral uterine horns. Three groups of rats with bilateral, left unilateral, or right unilateral artery ligation were compared with a control group for number and weight of fetuses at term. The results showed that the impaired rats produced significantly fewer fetuses than controls (means: 8.59 vs. 11.21, respectively; P less than .001) and those fetuses had lower mean birth weights than controls (5.295 g vs. 5.800 g, respectively; P less than .05). While conception was possible even in rats with impaired uterine blood flow, the differences at term suggest that impairment of the maternal blood flow may contribute toward intrauterine growth retardation and habitual abortion. The clinical significance of these findings and suggestions for future research are discussed.