The first thing we should mention is that an "epidural" is not always the same combination of medications. In fact, every anesthetist uses his own cocktail of drugs, and the dose can vary according to your needs and wishes. Besides the most well known regular epidural, it is also possible to choose a "walking epidural" or Combined Spinal-Epidural (CSE). This allows women in labor to be more mobile. So, on to the possible side effects. Perhaps the most common side effect is a sudden drop in maternal blood pressure. You will be checked regularly to ensure you and your baby are safe, and if your blood pressure does go down dramatically, you will be given additional medication to treat it, as it could reduce blood flow to your baby while you are in labor.
A leakage of spinal fluid can cause headaches in some women who have an epidural. You could feel sore where the needle is placed, feel ringing in your ears, shiver, have trouble peeing, and feel nauseous. Epidurals can also cause breathing problems for some women. In addition, because you will be required to mostly stay put in the same position during labor after a regular epidural, your labor could progress slower, or even stop completely. This could lead to further interventions like Pitocin to augment labor, or even a cesarean section. Women who have an epidural may feel numb and groggy for a while after labor too, along with possible headaches. This should clear up relatively soon after giving birth.