A hormone given by injection to induce or strengthen labour
Oxytocin
A hormone given by injection to start or strengthen labour and to control bleeding after birth.
What is Oxytocin?
Oxytocin is a hormone given by injection in maternity care to start (induce) labour, to strengthen contractions that are not progressing, and to help the womb contract to control bleeding after birth. The most important safety concern is that contractions can become too strong or too frequent, which can distress the baby and, rarely, lead to the womb tearing (rupture), so it is given in hospital with close monitoring of the contractions and the baby's heart rate. With prolonged use it can also cause the body to hold on to water, which can lower the blood's sodium level. It is always used under careful midwifery and medical supervision.
Education and reference only. This is a plain-language guide to Oxytocin — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Oxytocin is a hormone that the body makes naturally, which causes the womb to contract during labour and helps milk let-down for breastfeeding. As a medicine, a manufactured form is given by injection in hospital to start labour when there is a medical reason to do so, to strengthen contractions when labour is slow, and to help the womb contract firmly after the baby is born to reduce bleeding. It is given by a drip into a vein or as an injection by the maternity team, always with monitoring, and is not something used at home.
How it works
Oxytocin makes the muscle of the womb contract. During labour, giving it can start contractions or make existing ones stronger and more regular, helping labour progress. After the baby is born, it makes the womb clamp down firmly, which squeezes shut the blood vessels where the placenta was attached and so reduces bleeding. Because the strength and frequency of contractions depend on how much is given, the maternity team adjusts the drip carefully and watches the contractions and the baby's heartbeat closely to keep contractions effective but not excessive.
Company & origin
Originated / developed by: Specialist manufacturer (hospital use).
A hormone medicine used in UK maternity care to start or strengthen labour and to reduce bleeding after birth.
Practical use
How to take Oxytocin
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given by the maternity team as a drip into a vein or an injection in hospital, not taken at home.
- Your contractions and the baby's heart rate are monitored continuously while you receive it.
- The drip is adjusted carefully to keep contractions effective without becoming too strong or too frequent.
- Tell the team about any previous womb surgery, such as a caesarean, as this affects how it is used.
- The fluids you are given are watched, as prolonged use can make the body hold on to water.
Weighing it up
Advantages & disadvantages of Oxytocin
Advantages
- Helps start or strengthen labour when there is a medical reason to do so.
- Helps the womb contract firmly after birth to control and reduce bleeding.
- Allows the team to adjust the strength of contractions carefully with monitoring.
Disadvantages
- Contractions can become too strong or too frequent, which can distress the baby.
- Rarely, very strong contractions can lead to the womb tearing, especially after previous womb surgery.
- With prolonged use it can cause the body to retain water and lower the blood's sodium level.
Practical use
Good to know
The key safety point with oxytocin is getting the strength of contractions right. If contractions become too strong or too frequent, the baby may not get enough oxygen between them and can become distressed, and very rarely the womb itself can tear (rupture), which is more of a concern in women who have had previous womb surgery such as a caesarean. For this reason it is always given in hospital, the drip is adjusted carefully, and both the contractions and the baby's heart rate are monitored continuously. With prolonged use and large volumes of fluid, oxytocin can cause the body to retain water and lower the blood's sodium level, so fluids are watched. It is also used after birth to help the womb contract and reduce bleeding. All of this is managed by the midwifery and medical team, who explain what to expect.
Who should not take it / use with caution
- It is not used when contractions or the way the baby is lying make a normal birth unsafe, as judged by the maternity team.
- It is used with particular caution in women who have had previous womb surgery, such as a caesarean.
- People who have had a serious allergic reaction to it should not be given it.
Monitoring
- Continuous monitoring of contractions and the baby's heart rate during labour.
- Watching the amount of fluid given, as prolonged use can lower blood sodium.
- Checking blood loss and how firmly the womb contracts after birth.
Side effects
- Contractions that are too strong or too frequent, which can affect the baby.
- Nausea or vomiting in some women.
- With prolonged use, the body holding on to water and a low blood sodium level.
- Rarely, more serious effects such as the womb tearing, which monitoring is designed to prevent.
Key interactions
- It is used carefully alongside other medicines that affect the womb, such as prostaglandins used to ripen the cervix.
- Certain anaesthetic medicines can affect blood pressure when combined with it, which the team manages.
- The team reviews all your medicines as part of planning your care.
Available as: A solution given as a drip into a vein or by injection, in hospital.
Answers
Oxytocin: frequently asked questions
What is oxytocin used for?
It is a hormone given by injection to start or strengthen labour when there is a medical reason, and to help the womb contract after birth to control bleeding.
What is the main risk during labour?
Contractions can become too strong or too frequent, which can distress the baby and, very rarely, lead to the womb tearing, so it is given with close monitoring.
Why is it only given in hospital?
It needs continuous monitoring of your contractions and the baby's heart rate so the drip can be adjusted carefully, which is why it is always given by the maternity team in hospital.
Why does previous womb surgery matter?
Very strong contractions carry a higher risk of the womb tearing in women who have had surgery such as a caesarean, so it is used with particular caution in that situation.
Can it cause problems with prolonged use?
With prolonged use and large amounts of fluid it can cause the body to hold on to water and lower the blood's sodium level, so fluids are watched closely.
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.