Linda-S

Indications

Oxytocin is a hormone medicine used around childbirth. It is used to start (induce) labour or to strengthen weak contractions when there is a medical reason, to help the womb contract after the baby and placenta are delivered, and to prevent and treat heavy bleeding after birth (postpartum haemorrhage). It may also be used in the management of an incomplete or missed miscarriage, alongside other treatment. It is used only in a hospital or health facility.

How It Works

Oxytocin is a man-made copy of a natural hormone released by the pituitary gland in the brain. It makes the muscle of the womb contract more strongly and more often. After birth, these contractions squeeze the blood vessels in the womb and reduce bleeding. It also helps milk flow from the breast.

Dosage and Administration

Oxytocin is given only by a doctor, midwife or nurse, as an injection into a muscle or a vein, or as a slow drip (infusion) into a vein. For starting or strengthening labour, the drip rate is started low and adjusted by the care team as prescribed, while contractions and the baby's heartbeat are watched closely. After the birth of the baby, a single injection into a muscle (commonly 10 IU) is often given to help the womb contract and prevent heavy bleeding; further doses are given as prescribed.

Interactions

Prostaglandin medicines used to ripen the cervix or start labour (such as Misoprostol or Dinoprostone) strengthen its effect; they are not given at the same time, and the team leaves a safe gap between them. Some anaesthetic gases can weaken its effect and affect heart rhythm. Medicines that narrow blood vessels, used with certain anaesthetics, can cause a dangerous rise in blood pressure. Medicines that affect heart rhythm (QT prolongation) need extra care.

Contraindications

• When a vaginal birth is not advisable, for example placenta praevia (placenta over the cervix), the baby lying in an abnormal position, or the umbilical cord coming first.
• When the baby's head is too big for the pelvis, or there is a mechanical blockage to delivery.
• Signs that the baby is in distress before delivery is close.
• Very strong or very frequent contractions already present.
• Severe pre-eclampsia or severe heart disease (unless the specialist decides otherwise).
• Allergy to oxytocin.

Side Effects

Possible effects include nausea, vomiting, headache, flushing, a fast or irregular heartbeat, and low blood pressure if a large dose is given quickly into a vein. Contractions that are too strong or too frequent can reduce the baby's oxygen supply and, rarely, cause the womb to tear. Long infusions with a lot of fluid can cause water overload with low blood sodium (headache, confusion, drowsiness, fits).

Tell the doctor or midwife immediately if you have severe constant belly pain, heavy bleeding, chest pain, difficulty breathing, swelling of the face or a rash, a severe headache, confusion or fits.

Pregnancy and Lactation

Oxytocin is used only at the end of pregnancy for labour or after delivery, or in miscarriage management, under close medical supervision. Only tiny amounts pass into breast milk and they are broken down in the baby's stomach, so breastfeeding can continue.

Precautions and Warnings

Mother and baby are monitored throughout. Extra care is needed after a previous caesarean section or other womb surgery, after many previous births, with twins or a very large womb, and in heart disease, high blood pressure or kidney problems. Fluid intake and output are checked during long infusions.

Overdose

Too much oxytocin can cause very strong or continuous contractions, distress to the baby, tearing of the womb, heavy bleeding and water overload. The team stops the drip at once and gives emergency treatment.

Therapeutic Class

Oxytocic (hormone that makes the womb contract), posterior pituitary hormone.

Storage

Store in a refrigerator at 2 to 8°C, protected from light; do not freeze. Some products may be kept at room temperature for a limited time, as the leaflet says. Keep out of the reach of children.