What are the stages of labour? Why do i need to know this?

10 things to know about stages of labour

1. Labour is divided into 3 stages – 1^st, second and 3^rd.
2. The 1^st stage is until the neck of the womb, or cervix,is fully dilated (10cm).
3. The 1^st stage is then divided into 2 phases – the latent slow phase, until 4cm, followed by the faster, active phase. 
4. The 2^nd stage is from the cervix being fully dilated until the baby being born
5. The 2^nd stage is also divided into 2 phases – the passive phase, which is before you are ready to push and the active phase, which is when you are actively pushing.
6. The 3^rd stage is the delivery of the placenta.
7. The length of the latent phase of labour can last for ages, be very stop-start and be quite frustrating for some women. It does not mean that anything is wrong, it is just the body learning.
8. The length of the active first phase is on average 8 hours in first labours, but it can be more than double this (up to to 18 hours). It is quicker in second labours. We usually expect the cervix to dilate at around 0.5-1cm per hour but it can be much quicker.
9. The length of the second stage can also varies, but it is usual for women to push first babies out within 2 hours, and second babies within 1 hour. 
10. The placenta will usually deliver within 30 minutes of the baby, unless you did not have the injection, in which case it may take up to 1 hour.

Why is it important to understand the stages of labour?

Labour is the process of having a baby, and it is divided into three stages. The first two stages are whilst the cervix, or neck of the womb is opening until when the baby is born. The third stage is the delivery of the placenta.

It is helpful to understand what the first two stages are as this will help you understand what midwives and doctors say during labour, and it is also helpful to understand if induction of labour is discussed with you.

What is dilation of the cervix?

During labour, the muscle of the womb, or uterus, contracts and gradually these contractions cause the neck of the womb, or cervix to open up. The cervix starts of long and closed. If you were to look at the cervix, end on, it looks a bit like a doughnut without a proper hole in the middle, just a dimple. In most women during pregnancy, the cervix will be about 3-4cm long before labour starts. The first stage of labour is from when the contractions start, and the neck of the womb starts to change, until the cervix is fully dilated. Once the cervix is fully dilated, it means there is no cervix left and it is open enough to left the baby’s head through. The second stage of labour is the part of labour from when the cervix is fully dilated until the baby is born.

You will hear doctors and midwives during labour describe the dilation of the cervix in centimetres. This is not measured with a ruler, it is just an estimate from doing an examination with usually two gloved fingers, so it is not exact, it is just approximate. This means when two different people do an examination at the same time, they will sometimes come up with a different amount of dilation, just because of variation between how people estimate it. Neither is wrong or right, it is just that both are estimates. The estimates would not usually be that different from each other though, usually by only 1cm or so. It is also usual to hear doctors and midwives describing the length of the cervix. This is because the cervix has to shorten as well as dilate. By the time the cervix is around 4cm dilated, it will usually have lost most of its length by then. You may hear this described as being ‘fully effaced’.

What is the first stage of labour?

The first stage of labour is also divided into two different phases. These are the latent phase and the active phase.

The latent phase is the very first part of labour when the cervix changes from being long and closed, up until about 4cm. This stage of labour can be quite stop and start, with irregular contractions. It can also go on for a long time, with no fixed or expected length, especially if it is your first baby. It can even go on for days. When you hear people say they were in labour for a period of days, this is most likely to have been a long latent phase. A long latent phase does not necessarily mean anything is wrong, it is just the body learning what it needs to do. 

The second part of the first stage is the active phase of labour. This is from 4cm to full dilation. It is estimated that full dilation is the same as the cervix being 10cm dilated. This part of labour is when the contractions become stronger and more regular. The speed of this part of labour can vary, and it can be a longer in first labours. It lasts on average, in first labours, around 8 hours, but can last up to 18 hours.  It is common for the speed of the dilation to be faster up until around 8 cm and then sometimes go a bit slower for the last 2 cm. Usually, it would be expected for the cervix to dilate between 0.5 and 1cm per hour, approximately, although in some people it can be much faster. In second and subsequent labours, the length, on average is around 5 hours, and is unlikely to last longer than 12 hours.

What is the second stage of labour?

The second stage of labour is from when the cervix is fully dilated until the baby is born. This is also divided into two phases, a passive phase and an active phase. The passive phase is when the cervix is fully dilated but you are not actively pushing, and the active phase is when you are pushing. If you have an epidural for pain relief in labour, especially in first labours, the passive second stage can last upto 2 hours. During this time, the baby is moving slowly down the birth canal, and often rotating into the best position for delivery. The duration of pushing can vary, and is usually slower in first labours. If the baby has not been born after 2 hours of pushing in a first labour or 1 hour in a second labour, it would be usual to ask for a doctor to review and find out why the baby has not been born yet.

What is the third stage of labour?

After the baby is born, then the placenta is delivered. You will be offered an injection, given just as the baby is being born, to help with delivery of the placenta and to reduce the bleeding. Some women choose not to have this injection, in which case it can take longer for the placenta to deliver. The placenta usually delivers quite easily, and the midwife will gently pull on the cord and it slips out. Usually the placenta delivers within about 30 minutes of the baby being born. If you have not had the injection, then it can take up to 1 hour.