What it looks like

Teeth chattering hard enough to be heard. Legs jumping on their own. Arms shaking so much that holding a baby feels unsafe. It usually starts within minutes of the birth and settles within an hour or so, though it can come back in waves.

Most women are not cold when it happens, which is the confusing part. The shaking is not always temperature-driven, and feeling perfectly warm does not stop it.

Why it happens

There is no single cause, and no UK national body publishes how often it occurs after a vaginal birth. The recognised contributors are:

The anaesthetic. Shivering is one of the best-documented effects of both regional and general anaesthesia. The Obstetric Anaesthetists' Association publishes shivering as a frequency for caesareans under general anaesthetic: 1 in 3.
Heat loss. Theatres are cool, fluids are cold unless warmed, skin is exposed, and a body that has been working hard loses heat quickly once it stops.
The hormonal and physiological drop after birth. A sudden change in circulating hormones and blood volume as the placenta separates.
Adrenaline. The end of an intense physical event.

The NHS lists shivering among the ordinary side effects of a general anaesthetic in any operation, alongside feeling sick, a sore throat, drowsiness, thirst and confusion, and says side effects "will usually get better within a few minutes or hours".

What the room does about it

More than you might think, and it is written into guidance rather than left to habit. NICE's caesarean guideline has a section headed prevention and management of hypothermia and shivering:

Warm intravenous fluids and blood products used during a caesarean to 37 degrees Celsius using a fluid warming device.
Warm all irrigation fluids used during a caesarean to 38 to 40 degrees Celsius in a thermostatically controlled cabinet.
"Consider forced air warming for women who shiver, feel cold, or have a temperature of less than 36 degrees Celsius during caesarean birth."

Forced air warming is the inflatable blanket with warm air blown through it. If you are shaking on the table and one appears, that is the recommendation being followed.

After a vaginal birth the measures are simpler — blankets, a warm room, dry clothing, and skin-to-skin with your baby, which warms you both. NICE asks that the baby be dried and covered "with a warm, dry blanket or towel while maintaining skin-to-skin contact", and that the baby's temperature is checked and is in the normal range.

Can you still hold your baby?

Usually yes, with help. Shaking arms are a reason for someone to support the baby with you rather than a reason to separate you. NICE's expectation is to "minimise separation" and to avoid moving a baby away in the first hour for routine procedures.

If the shaking is severe enough that you do not feel safe, say so and ask your birth partner to hold the baby skin-to-skin until it passes. NICE explicitly asks that if the woman is not well enough, "encourage her birth companion to have skin-to-skin contact instead". Handing over for ten minutes is not a lost golden hour.

When shivering means something else

Three situations change the picture, and all three are things the staff around you are already watching for.

Infection

Shivering with a fever is different from shivering alone. NICE's intrapartum thresholds are a temperature of 38 degrees Celsius or above on a single reading, or 37.5 degrees or above on two consecutive readings an hour apart. That is why your temperature is taken alongside your pulse and blood pressure after the birth rather than only during labour.

The Obstetric Anaesthetists' Association also notes that fever can follow an epidural: "It can happen in the hours after an epidural and last for a few days. Your healthcare team may offer you antibiotics if it is caused by an infection."

Blood loss

Shaking with a fast pulse, dizziness, feeling faint or heavy bleeding is a different event and needs saying out loud immediately. Nobody will mind being told.

A transfusion reaction

If you are receiving blood, shivering is one of the things being monitored for. The RCOG lists mild effects of a transfusion including "a mild fever, a rash and/or itchiness", and severe ones — "difficulty in breathing, severe headaches and a sudden fall in blood pressure" — as a transfusion reaction, in which case "the transfusion will be stopped immediately". Your blood pressure, temperature and heart rate are checked before and during a transfusion for this reason.

What helps

Warm blankets, a hat if you want one, dry clothes as soon as practical, a warm drink once you are allowed one, and skin-to-skin. Ask for a warming blanket if you are shaking in theatre or recovery — NICE's recommendation means it should be available.

Nothing needs to be taken for it. It stops on its own.

What to say, and when

Tell your midwife you are shaking, even if it seems obvious. It takes one sentence and it prompts a temperature and a pulse, which is exactly the check that separates the ordinary version from the two that are not.

Once you are home, shivering is on the list of symptoms that should prompt contact rather than waiting. Shivering with a temperature, with pain, with foul-smelling discharge or with heavy bleeding needs urgent advice, not a wait-and-see. That combination is the one that matters, and it is worth knowing before you leave the building.

Afterwards

Many women remember the shaking more vividly than the birth itself, partly because nobody warned them and partly because it looks alarming to everyone else in the room. It is one of the more common things people raise at a birth debrief, and the answer is almost always the reassuring one.

Shaking and Shivering After Birth