The effect of an intrauterine foreign body on the sodium and potassium concentrations of the uterine fluid of the rat

Abstract The presence of an intrauterine silk thread, in one uterine horn of the rat, does not significantly change the uterine fluid potassium concentration at estrus or at diestrus; it does, however, prevent the increase of the uterine fluid potassium concentration which is normally found at the time of implantation on day 6 of pregnancy. The mean uterine fluid K + was 41.2 meq/L in the uterine fluid of the control horn and 26.3 meq/L in the uterine horn with the foreign body on day 6 of pregnancy. This difference is highly significant (p It is suggested that the abnormally low uterine fluid potassium concentration may be toxic to the blastocysts and may also prevent implantation of any surviving blastocysts by raising the membrane potential of the endometrium.