Inducing labour, or induction of labour, is artificially stimulating childbirth. In most cases, labour starts naturally.
If a pregnancy isn't proceeding as it should, or if the health of the mother or baby is threatened, doctors and midwives will speed up the process by inducing labour.
Why is labour induced?
There are a number of reasons for inducing labour, from a late delivery to a medical complication in the pregnancy. Your midwife or obstetrician should explain why you are being offered induction, and the risks and benefits.
Your doctor might induce labour if:
- You are one to two weeks past your due date. Your obstetrician should discuss this possibility at your routine 38 week antenatal appointment. After 42 weeks, you and your baby are at greater risk of complications, and the placenta that nourishes your baby in the womb may have diminished so much that it can no longer properly feed your baby. The baby also may breathe in his first bowel movement (called meconium), which can block his airways.
- The membrane that holds the amniotic sac surrounding your baby breaks (your "waters break") and you don't go into labour on your own (once your waters break, you and your baby are at greater risk of infection).
- You have a health condition, such as high blood pressure (pre-eclampsia), gestational diabetes, bleeding, or an infection in your uterus, which puts your health or your baby's health at risk.
- Tests show that your baby is no longer growing or developing at a normal rate, or the baby's heart rate is abnormal.
How is labour induced?
Normally during labour, the lower end of the uterus (cervix) softens. This is called ripening. The cervix thins out (effaces) and opens (dilates). In order for the baby to be born, the cervix must be fully effaced and dilated to allow the baby's head to get through.
Before the doctor will induce labour, he or she will check your cervix and the baby's position to find out whether you are far enough along for induction to work.
Doctors use medications and other methods to efface and dilate the cervix artificially so that the baby can be born. Labour induction techniques include:
- Sweeping the membranes. The midwife or obstetrician will insert a gloved finger into your vagina and move it back and forth to separate the membrane that connects the amniotic sac to the wall of the uterus. This is called "sweeping the membranes" and it causes the body to release hormones called prostaglandins, which ripen the cervix and may lead to contractions. You may feel some cramping and have some spotting after this procedure. A midwife or doctor may carry out this procedure during an internal examination in the clinic or at your home.
- Ripening the cervix. Medications called prostaglandins can dilate your cervix enough to prepare it for labour. Prostaglandins are manmade versions of chemicals in the body that both ripen the cervix and stimulate the uterus to contract. You take prostaglandins either by mouth or via a gel or pessary inserted in the vagina.
- "Breaking your waters". If your cervix is already at least partially dilated, your doctor can "break your waters" (amniotomy) by making a hole in your amniotic sac. Once your amniotic sac has broken, you should start having contractions. You'll need to deliver within about 24 hours to prevent infection.
- Triggering contractions. The drug oxytocin can bring on contractions to induce or move your labour along. Oxytocin is a hormone that triggers and strengthens contractions. It's delivered through an intravenous (IV) tube in your arm. Your doctor will start with a small dose and will gradually increase it until your contractions are strong and frequent enough for the baby to be born.
Apart from sweeping the membranes, which can be done at home or in the clinic, these other methods of inducing labour will be done in a hospital where both you and your baby can be carefully monitored.
Some women go into labour and deliver within a few hours after induction of labour begins. Others take one or two days to begin labour. If you don't go into labour with any of these methods, especially once your waters have broken, you may need to have a caesarean section.