If your cervix
is stenotic, you can accumulate "fluid" in your endometrial cavity
which may be mucus, not blood?
Bleeding will usually not occur if your cervix is closed
The fact that " no thickening" of your endometrium
was noted on sonogram
is reassuring and means you probably do not have " hematometra" and that the "fluid" may resolve spontaneously in weeks to months.