Its not recommended to wait for symptoms to appear if there is indication of surgery.
Fibroids in some cases can cause abortion,depends on size,location and type.
For Pcos,try to work out and lose some weight(if you are overweight),try to take balanced diet.
For
thyroid, regularly take your thyroid medication without fail and avoid some vegetables like cabbage,cauliflower,carrots etc(they can cause goitre)
Consult for further advice