My wife gave birth under spinal epidural anesthesia. 3 days later she developed mild loss of feeling on two toe (left foot only). is it a side effect?

Unrelated to spinal: I have delivered thousands of babies to women with spinals or epidurals, and I have never seen a case of nerve damage. It can happen but is exceedingly rare. Also, if it were to happen, it would be a much larger affected area, such as an entire lower extremity. I think there must be a more distal cause. like ill-fitted shoes. Women's shoe size can go up after birth, so I would check that.

Couple thoughts: Unlikely due to injection, but could be due to positioning at time of labor and delivery or later. Tell your doctor about this, and have him/her examine. Should depart over next few weeks, but if persistent , would recommend EMG testing.

Numbness in toes: Numbness in the toes most certainly could be a side effect of an epidural, but should not last very long after the injection/anesthesia. The numbness could be related to the injection, or she may have another pathology, such as a Neuroma, a nerve impingement near the toes. If the problem persists, see a local Podiatrist for evaluation and treatment.