Induction of Labour
Induction of labour is the deliberate start of labour by means of artificial methods, before spontaneous, natural onset of labour. This method is used commonly in private practice in South Africa and is second only to Caesarean Sections. Inducing labour should have a sound reason for doing so.
Indications for Inductions
If an induction is done for the baby, it should be asked whether it is safer for the baby outside the uterus than inside. If it is done for maternal reasons, it should be done because continuing the pregnancy will endanger the life of the mother.
Maternal Indications
- Uncontrolled high blood pressure
- Intra uterine foetal death
- Premature rupture of membranes (depends on duration)
- Cancer, where chemotherapy or radiotherapy is indicated
Baby Indications
- Intrauterine growth retardation, where the foetus is not growing due to placental insufficiency
- Post-maturity – if the foetus is moving well, most care providers will induce by 10 days after the due date, although induction can wait until 42 weeks
Contra-indications (when it should not be done)
- Previous caesarean sections (depending on reason for previous Caesar)
- Cephalopelvic disproportion, where baby is too big for the pelvis and no engagement (baby has not moved into pelvis) has occurred after 40 weeks gestation
- Foetal distress
- Malpresentations, as in breech baby or transverse lie
- Placenta praevia, where placenta is lying in front of the cervix (birth canal)
- Congenital abnormalities of the uterus or cervix
- Active herpes infection
- Multiple pregnancies
- Mother is tired of waiting
Factors affecting the success or failure of an induction
The closer to 40 weeks gestation or thereafter, the higher the chances of success.
The sensitivity of the uterus to stimulus and the amount of Braxton-Hicks contractions occurring. Whether it is a first baby or not is also important, as first pregnancies are less likely to respond well to induction than second or third pregnancies.
The technique of induction and the state of the cervix. For a successful induction the cervix should be at least 1-2cm open, 1cm or less long, baby’s head must be in the pelvis, the cervix must be softening and come forward to the central or anterior position. This is called the Bishop score and should be assessed before any induction is performed.
Methods of Inducing
Surgical induction can be done if the induction is not urgent. This is done by stretching the cervix and stripping off the membranes from the lower segment, called a stretch and sweep. Breaking of the membranes also classifies as a surgical induction. After the stretch and sweep the mother can wait a few days for the onset of labour, but after artificially rupturing the membranes labour needs to commence within 6-12 hours or risk infection.
Medical induction is generally done if the cervix is not ripe or favourable for an induction. The ideal is to ripen it before with prostaglandin gel or tablet, placed in the back of the vagina behind the cervix. A percentage of women will go into spontaneous labour after this. If not, the cervix should be re-evaluated after four to eight hours and the procedure repeated until the cervix starts to become favourable, and this should not exceed 24 hours. Unsupervised administration can lead to over stimulation of the uterus and is not easily reversed.
If the cervix is favourable, prostaglandins or oxytocinon (artificial oxytocin hormone, in SA Syntocinon, in USA Pitocin) can be used. This is administered through a drip. It is started at a slow rate and increased every half an hour until good strong contractions occur, three strong contractions in every 10 minutes, or until the maximum dosage is reached. Contractions stimulated intravenously by oxytocinon are usually physiological. The amount administered can be closely controlled and if over stimulation of the uterus occurs, the infusion is discontinued and the effect of the oxytocinon stops within two to three minutes. Enemas and hot baths can possibly sensitise the uterus to go into labour, although the effectiveness of this method is doubtful.
Why it’s only for emergencies
In any method of induction the chances for an operative delivery (caesarean section, forceps or vacuum delivery) is higher due to dystocia (see below) and foetal distress. The incidence of opting for pain relief like Pethidine, Aterax or an epidural is also increased, because of the artificial introduction of hormones which does not allow the mothers natural hormones to kick in when they are supposed to. This results in more painful and rapid contractions for the mother.
What is dystocia?
Dystocia refers to a difficult or prolonged labour, and can either be cervical or uterine based. With cervical dystocia normal uterine contractions occur and the cervix normally effaces or thins out, but does not dilate adequately. Cervical dystocia generally occurs as a result of previous scarring and lesions, or cervical cancer. Uterine dystocia happens when a constriction ring or spasm forms in the uterus and prevents the foetus from descending. It occurs in one in 10 000 labours.
Did you know?
An elective or social induction is done solely for convenience of the mother or doctor, and offers no benefit to baby. Social inductions – a highly controversial subject – is under critical scrutiny, since the risks are very real to both mother and foetus, and there is an increased incidence of unnecessary caesarean section after failed induction of labour.
Inductions are also done to allow doctors to practice ‘daylight obstetrics” says Dr. Marsden Wagner, a neonatologist who served for 15 years as a director of women’s and children’s health in industrialized countries for the World Health Organization. “It means that as a doctor, I can come in at 9 a.m., give you the pill, and by 6 p.m. I’ve delivered a baby and home having dinner.”
Tips to avoid labour induction
- Recognise that, according to almost all experts, a normal pregnancy lasts between 38 and 42 weeks. In your mind, add two weeks to your due date in case your pregnancy lasts 42 weeks.
- Understand that many researchers believe that it’s the baby that starts labour. Studies suggest that once the baby is fully mature and ready for life outside the womb, he releases a substance that tells the mother’s body to start the process of labour. In most cases, the best way to know that your baby is ready to be born is to wait for labour to begin on its own.
- Choose a care provider who induces labour only for medical reasons.
- Don’t be induced without a medical reason. Be aware that a large baby is not a medical reason for induction.According to experts, including the American College of Obstetricians and Gynecologists, induction for suspected large babies does not improve outcomes for babies and almost doubles the risk of a cesarean for mothers.
- Stay active and exercise at least 30 minutes most days at a moderate pace. Research indicates that healthy women who exercise regularly throughout pregnancy are less likely to need to be induced or have their labour speeded up.
- Stay well-nourished and drink plenty of fluids. If there’s a concern with the baby being overdue, tests (such as a biophysical profile and amniotic fluid index) may be scheduled to evaluate the baby. Several studies have found links between maternal dehydration and poor results on these. If you are scheduled for these tests, be sure to drink plenty of liquids and eat well in the days before the tests.
- If your water breaks before labour begins, ask your care provider to allow you time to go into labour on your own. Most women begin labour soon after their water breaks, and 90% will be in labour within 2 days of their water breaking. There’s no need to rush labor unless you or your baby are in danger or there are signs of infection. Follow your care provider’s advice for reducing the possibility of infection and ask him or her to do vaginal exams only when medically necessary.
- If labour induction is planned for non-emergency medical reasons or because you are getting close to 42 weeks, discuss alternative ways of inducing labour with your health care provider. To start labor, research suggests the use of acupuncture, nipple stimulation, and “sweeping the membranes,” a procedure in which the care provider uses her fingers gently to separate the bag of waters from the cervix during an internal exam. Many have suggested the use of sexual intercourse to help labor begin, but these methods haven’t been studied in high quality research.
Augmentation of Labour
Augmentation of labour means that labour has spontaneously started and preparations are used to strengthen or ‘boost’ the contractions. This has not proven to be of benefit as it does not shorten the labour period and only makes the labour process more painful and uncomfortable for the mother.
To possibly prevent this from happening, the labouring mother should stay at home until her labour is well established.
