Local cold stress to the soles induces retroplacental hemorrhage in rats

The aim of this study was to investigate the effect of local cold stress to the soles on placental histology in rats. Pregnant rats were subjected to a cold provocation (0 degreesC, 12 degreesC) and room temperature (23 degre esC) for 15 and 30 minutes. During cold stimulation and at the control temp erature, uterine blood now and uterine contraction were measured simultaneo usly. Histological studies of the placentas of these rats were also perform ed. Cold stress at 0 degreesC and 12 degreesC significantly decreased uteri ne blood flow (P < .005, P < .02) compared with controls (23 degreesC). The decrease in uterine blood flow was greater at 0 degreesC than at 12 degree sC stress. Cold-induced stress (0 degreesC) also evoked an isometric tensio n with increased frequency and amplitude in the rat uterus (P < .003, P < . 0002) compared with controls (23 degreesC). Stimulation at 12 degreesC did not induce any uterine contractions. Placental histology of rats stressed a t 0 degreesC revealed hemorrhages into the decidua basalis. These findings suggest that local cold stress decreases uterine blood flow and increases u terine contraction, resulting in retroplacental hemorrhage in rats. This mo del may account for human abruptio placentae.