Toxemia can also produce fetal distress that would necesitate a Csection. Meconium is a symptom of fetal distress also, can be caused by several things. They're not the same thing, but the symptoms from different problems can over lap.
Does this sound as confused as I think it does?
Pinz
(former La Leche League Leader)
I think that summed up the difference well.
Toxemia: potential CAUSE of fetal distress.
Meconium (in amniotic fluid): potential SIGN of fetal distress.