What it is and how it is placed

The NHS: "an epidural is a type of local anaesthetic. It numbs the nerves that carry the pain impulses from the birth canal to the brain. It should not make you sick or drowsy."

The sequence, as the NHS and the HSE both describe it: a drip is run into a vein in your arm first; you sit curled forward or lie on your side; the anaesthetist cleans your back with antiseptic, numbs a small area with local anaesthetic, then introduces a needle and passes a very thin tube through it near the nerves carrying pain from the uterus. The needle comes out, the tube stays. Medicines — usually a mixture of local anaesthetic and an opioid — go through the tube.

Timing: the NHS says "it takes about 10 minutes to set up the epidural, and another 10 to 15 minutes for it to work." ACOG gives a comparable figure — "pain relief should begin within 10 to 20 minutes after the medication has been started." Top-ups can be given by your midwife, or you may be able to give them yourself through a machine.

Where you can have one

This is the constraint that shapes birth plans. NICE requires women to be told that an epidural "is available only in obstetric units so transfer will be necessary if she is in another setting." The NHS says the same from the staffing side: "an anaesthetist is the only person who can give an epidural, so it will not be available at home. If you think you might want one, check whether anaesthetists are always available at your hospital."

That last sentence is a genuinely useful question to ask on a hospital tour, and so is whether "mobile" epidurals are offered. The NHS notes that walking with an epidural also requires the baby's heart rate to be monitored remotely by telemetry, "and many hospitals do not have the equipment to do this."

How well it works

Better than anything else available, but not perfectly. The NHS: "in most cases, an epidural gives complete pain relief", while also stating that "an epidural can provide very good pain relief, but it's not always completely effective in labour." NICE requires that women are told it "provides more effective pain relief than opioids" and, in the same breath, that "it may not always be fully effective and may need to be adjusted or replaced."

The Obstetric Anaesthetists' Association puts numbers on the gap. Out of 100 people who had an epidural during labour, "about 10 needed additional pain relief, as well as the epidural", and "about 5 had to have the epidural re-sited". If yours is not working well, the options are more anaesthetic through the tube, a change of position, re-siting the catheter, or a different type of anaesthetic — so say so rather than waiting.

Side effects that are common enough to expect

Heavy legs. The NHS: "an epidural may make your legs feel heavy, depending on the local anaesthetic used." NICE says you can mobilise with assistance if a midwife trained in epidural care confirms you have sufficient leg strength and sensation, "but their legs may feel heavier than usual."
Difficulty passing urine. A catheter may be put into the bladder. The HSE notes it "stays in place for up to 8 hours after the birth."
A drop in blood pressure. The NHS calls this rare "because the fluid given through the drip in your arm helps to maintain good blood pressure." NICE requires blood pressure to be measured every 5 minutes for 15 minutes when the epidural is established or topped up with a larger bolus.
Itching, nausea and shivering, which ACOG attributes largely to the opioid component. Itching can be treated with another medicine.
Fever. Listed by both ACOG and the OAA.
A sore back for a day or two. The NHS is explicit that this is short-lived: "epidurals do not cause long-term backache." NICE states the same, and so does the OAA.

Headache, and the rare risks with numbers

The NHS: "you may get a headache after an epidural. This happens in about 1 in 100 cases and can be treated." NICE warns that "complications during insertion of the epidural may cause a severe postnatal headache." The OAA notes it can start between one day and one week afterwards, and may be mild and settle with over-the-counter pain relief or severe and need hospital treatment.

The OAA's 2025 risk leaflet gives figures for the rarer outcomes, per number of people who had an epidural:

Local anaesthetic toxicity, which can cause seizures or cardiac arrest: about 1 in 1,000.
Temporary nerve damage — a weak, numb or tingly leg, buttock or foot, normally recovering by itself over days or weeks: 8 in 20,000.
Permanent nerve damage: about 1 in 20,000.
Meningitis: 1 in 50,000.
Infection in or around the spine: 2 in 200,000.
Blood clot around the spine: 1 to 2 in 200,000.
Paralysis: 2 in 500,000.

The NHS separately notes tingles or pins and needles down one leg after having a baby in about 1 in 2,000 cases, adding that this "is more likely to be the result of childbirth itself rather than the epidural."

The disagreement worth knowing about

Two reputable UK sources currently say different things about instrumental birth, and you may meet both.

NICE's 2023 guidance requires women to be told that an epidural "is associated with a longer second stage of labour and an increased chance of birth with forceps or ventouse". The NHS repeats this: "epidurals can prolong the second stage of labour... this means that forceps or a ventouse may be needed to help deliver the baby."

The Obstetric Anaesthetists' Association's leaflet, first published in September 2025, states that "according to the latest evidence" epidurals "do not make the use of ventouse or forceps more likely". It also says they do not make a caesarean birth more likely, do not make the baby drowsy or cause long-term harm, and do not cause back pain after childbirth.

Both sources agree on caesarean risk and on backache; they differ on instrumental birth, and the difference reflects how recently each read the evidence. Worth asking your anaesthetist directly.

NICE also describes a mitigation the NHS explains well: with an epidural, waiting longer before pushing "reduces the chance you'll need an instrumental delivery". NICE allows delayed pushing of up to 2 hours after full dilatation for a first baby and 1 hour for subsequent births.

What else changes once it is in

NICE: continuous cardiotocography for at least 30 minutes while the epidural is established and after each larger top-up; hourly assessment of the level of block; and a review by the anaesthetist "if the woman is not pain-free 30 minutes after each administration". You should adopt any position you find comfortable, including upright — with one exception, "except lying flat on their back". The epidural is continued "until after completion of the third stage of labour and any necessary perineal repair."

ACOG lists serious complications as "very rare", naming breathing problems if the anaesthetic reaches the spinal fluid, numbness or rapid heartbeat if it enters a vein, and injury to the spinal cord or nerves. On the baby: "the overall risks for your baby are low", with opioid effects that are short term, and it adds a point rarely made — "unrelieved pain during labor and delivery also has side effects, including changes in your breathing and an increase in stress hormones that can affect your baby."

Epidural in Labour