The stages of labour

Labour is divided into three distinct parts:

Stage 1:  The first part starts when contractions are regular and strong and ends when the cervix (the neck of the uterus, or womb) is open to the point that it cannot be felt on examination, also known as 10cm or fully dilated.

Stage 2: The second part of childbirth begins with full dilatation and ends with the birth of the baby. At this stage the umbilical cord is clamped and cut.

Stage 3: The third stage of labour starts after delivery of the baby and ends with delivery of the placenta and membranes (the pregnancy sac).

The hormone oxytocin, released during and following birth, causes the uterus to contract. During the third stage, contractions cause the placenta to detach from the uterine wall. Some women feel the need to bear down gently at this stage to aid the expulsion of the placenta, but this is a very gentle sensation, not painful and very different to delivering a baby. If you have a caesarean section, the third stage is performed by removing the placenta during the operation.

The time spent waiting for the placenta to deliver is also the first time you will be meeting and getting to know your baby. This is a very special time; professionals are sensitive to this and will try their best to minimise any disruptions or intervention.

Usually, you will have discussions with your midwife about the different options for the third stage before you go into labour. These can be noted in your birth plan. You can choose between two main approaches to “managing” the third stage of labour: physiological management and active management.

A physiological, or natural, third stage

This is when the placenta is allowed to deliver without intervention from health professionals. Drugs are not given routinely and the midwife or doctor does not apply traction (pull) to the umbilical cord (which is attached to the placenta) to hasten delivery. A physiological third stage may take longer to complete than an active third stage, but most are completed in 20 minutes.

As breastfeeding can increase the release of oxytocin, breastfeeding during a physiological third stage can help the placenta deliver.

Things to know about a physiological third stage:

• About 5% of women find that they get nausea and vomiting during the third stage.
• There is a 3% risk of significant bleeding (volume of blood lost is more than one litre).
• There is a 4% risk of needing a blood transfusion.

Sometimes during a physiological third stage bleeding is more than expected and it may be recommended that you switch to an active third stage before blood loss becomes significant.

An active, or managed, third stage

Active management of the third stage happens when drugs are administered routinely to reduce the length of the third stage and minimise blood loss. The drugs used are an artificial version of the hormone oxytocin, usually given as an injection into your bottom or thigh, after the delivery of the baby. They act to increase and aid the action of the body’s natural oxytocin. These can make you feel more nauseous than you would do otherwise. The doctor or midwife will also gently pull on the umbilical cord (controlled cord traction) after the placenta has separated to help it to deliver faster.

You may be advised to have an active third stage if you have risk factors for postpartum haemorrhage (PPH) including a big baby >4kg, a BMI >35, twins, you have previously had three babies or more or a previous PPH. Additionally, if your labour was prolonged, you had a temperature in labour or had an instrumental delivery, then you will also be recommended an active third stage.

Things to know about an active third stage of labour:

• It is shorter than a physiological third stage.
• About 10% of women get nausea and vomiting.
• The risk of significant bleeding is 1.3%. This is lower than a physiological 3^rd
• There is a 1.4% risk of needing a blood transfusion.

Which type of third stage should you choose?

The choice is yours and it is important you feel comfortable making the decision. The National Institute of Clinical Excellence (NICE) who set the standards and guidance for the care of pregnant women in labour, recommends that all women have an active third stage to reduce the risk of PPH. If you are low risk for a PPH, a physiological third stage can also be a good choice and you will be supported either way.

Timing of umbilical cord clamping

The baby’s umbilical cord is normally clamped and cut fairly soon following birth. The timing of cord clamping is important because blood continues to pass between the baby and the placenta following the birth if the cord is not cut – research evidence suggests that blood flow between the placenta and the baby can continue for several minutes after the baby is born. This continued passage of blood (sometimes called placental transfusion) can influence the baby’s blood volume immediately following birth, and this can influence iron stores for several months. The aim is to always allow at least one minute after delivery before the cord is cut, even in an active third stage. Often during a physiological third stage the cord is not clamped and cut for several minutes, until the pulsations have stopped signifying that the blood flow has stopped.

Some maternity units have a policy about when cords should be clamped and cut, so you may want to ask your midwife about this.

What if the placenta fails to deliver?

A placenta is ‘retained’ if:

• Active 3^rd stage: the placenta has not delivered within 30 minutes of baby’s birth
• Physiological 3^rd stage: the placenta has not delivered within 60 minutes of baby

Some factors increase the chance of a retained placenta – for example, if you have had a retained placenta before, if the first or second stage of labour is long, if you have a full bladder, if you have had a caesarean section before, if your baby is preterm or stillborn, or if you are over 30 years old.

There are three main reasons why a placenta doesn’t deliver:

1. the placenta is trapped behind a tightly closed cervix
2. contractions are not strong enough to detach the placenta from the uterine wall properly or
3. the placenta is abnormally attached to the uterine wall.

 

More time may be allowed for the placenta to deliver if bleeding is minimal, but the chance of increased bleeding rises if the placenta is retained, so your midwife or doctor may suggest interventions to try and help the placenta deliver around this time.

These interventions are often all that is needed, but sometimes a woman may need to have her placenta removed in the operating theatre. In this case an existing labour epidural or spinal anaesthetic will most likely be offered and the retained placenta is removed vaginally by hand (manual removal of the placenta). Antibiotics will be given, as infection risk is increased when a placenta is removed manually.

• The third stage of labour begins when the baby is born and ends with the delivery of the placenta.
• You can choose to have either a physiological or an active third stage of labour.
• A physiological third stage is when the placenta is allowed to deliver without intervention from health professionals.
• Released during and following birth, the hormone oxytocin causes the uterus to contract, helping deliver the placenta.
• An active third stage is when drugs are administered to reduce the length of the third stage. The drugs increase the strength of the contractions, which helps detach the placenta from the uterine wall.
• A physiological third stage can last longer than an active third stage, but most don’t last longer than 20 minutes.
• The amount of bleeding is also greater during a physiological stage than it is during an active third stage, but in many cases the amount of blood loss is not severe and most women are able to have a safe physiological third stage.
• There are some circumstances under which a midwife or doctor may recommend an active third stage over a physiological third stage. For instance, if they’ve given birth to a large baby, have had several previous babies, are obese, or have retained their placenta, then they are at a higher risk of heavier bleeding, and an active third stage is thought to be safer.
• Because blood continues to flow between the placenta and the baby for several minutes after birth, influencing the baby’s blood volume and iron stores for several months, the timing of the cord clamping and cutting is important. The cord tends to be cut sooner after birth in an active third stage than it is in a physiological third stage.
• If the placenta fails to deliver within 30-60 minutes of the birth, it is ‘retained’. Different interventions can help deliver the placenta, but sometimes it may need to be removed by hand, a procedure known as the manual removal of the placenta.

Further information

Sheldon W R, Durocher J, Winikoff B, Blum J, Trussell J (2013). How effective are the components of active management of the third stage of labor? BMC Pregnancy and Childbirth 13(1): 46.

Farrar D, Airey R, Law G, Tuffnell D, Cattle B, Duley L (2011). Measuring placental transfusion for term births: weighing babies with cord intact. BJOG 118: 70-75.

Farrar D, Tuffnell D, Airey R, Duley L (2010). Care during the third stage of labour: A postal survey of UK midwives and obstetricians. BMC Pregnancy and Childbirth 10(1): 23.