Hi.
Thanks for your query.
Noted the history IBS in mother, you being pregnant and started with rectal itching, and leakage of fecal matter.
This indiccates rather that you may be suffering from
anal fissure with least pain and can have hemorrhoids also due to
pregnancy.
The leakage may be due to the same factors.
There is no reason of flare up of IBS unless you are stressed and have anxiety.
Since you are pregnant, all the routine treatment and tests have to thought of before doing.
I would advise you the following:
Get the stool, blood and urine tested .
Ultrasonography of the abdomen is very safe procedure.
Per-
rectal examination and proctoscopy may be done with care but
colonoscopy avoided.
Probiotics, activated charcoal can be taken and rest of the treatment as per the findings