Do Epidurals Lower Blood Pressure?
Epidurals are the most popular form of pain relief used during labour. As with all medical procedures there are risks and benefits and it is important to know an epidural can create the need for further interventions. But do epidurals lower blood pressure?
The answer is yes. One of the most common side effects of epidurals is a drop in blood pressure (hypotension). While low blood pressure might seem fairly mild, it can have disastrous consequences.
Low blood pressure can cause symptoms such as:
- Dizziness or feeling faint
- Blurred vision
- Lack of concentration
- Unusual thirst
- Cold and clammy skin
- Rapid breathing
- Increased heart rate
Prolonged hypotension can become serious and, if untreated, can lead to shock, heart attack, heart damage, kidney failure, and stroke.
During pregnancy and labour, your baby relies on blood flow to the placenta to ensure adequate oxygen and nutrition are supplied. This is particularly important during labour, when each contraction causes blood flow to the placenta to be reduced momentarily.
After the contraction ends, blood flow is restored and oxygentated blood is available for the baby. If the amount of blood flowing to the uterus is reduced, the baby cannot get enough oxygen. This can cause fetal distress and, if it occurs over a period of time, can cause damage to organs, brain damage and even death.
How Do Epidurals Cause Low Blood Pressure?
Epidurals cause low blood pressure due to the effect of the local anaesthetic used. The anaesthetic blocks the nerves that regulate blood pressure, causing blood to pool rather than be pumped around the body as usual. Because almost all women who have epidurals experience low blood pressure, standard procedure is to administer IV fluids before placing an epidural.
IV fluids can quickly replace lost blood volume and increase blood pressure. The amount of fluid needs to be monitored carefully, as too much fluid can lead to a condition called pulmonary edema. This is when the lungs fill with fluid, and it can lead to respiratory failure.
If you have an epidural, usually you will be placed in a semi reclining position, slightly tilted onto your left side. It’s important to avoid lying flat on your back, as the pressure of uterus and baby can compress the major blood vessels (aorta and vena cava), leading to even lower blood pressure.