When making decisions on maternity care options, a woman is faced with a plethora of possibilities. From the time a woman discovers she is pregnant, the choices can sometimes feel like more of a burden than an opportunity, as it can take serious time and effort to study all the risks and benefits to every option in maternity care. Research shows that women who are informed and confident about their birth choices tend to have fewer interventions and fewer complications compared to women who have done little to no preparation for their birth. At 42 weeks, we are trying to take the effort out of the task of researching and to present concise and thorough guides to some of the more frequently asked questions about common maternity care options in pregnancy, labour and childbirth. Today, 42 weeks looks at: Induction.
What is induction?
An induction of labour is when a doctor or midwife uses various methods to artificially initiate or accelerate labour. such as:
- a membrane stretch and sweep
- a pessary or gel
- artificial rupture of membranes (ARM)
- a hormone drip
A membrane stretch and sweep is when a doctor or midwife sweeps their finger around the opening of the cervix to stimulate labour. A sweep is when the doctor or midwife carefully separates the membranes that surround the baby from their cervical attachment. It is not recommended to perform a stretch and sweep before 40+ weeks and if the cervix is unfavourable . This method of induction is not always effective in starting spontaneous labour so it may be offered again or it may lead to the choice of having a pessary (or gel) containing prostaglandin inserted into the vagina to help ripen the cervix and stimulate contractions.
A pessary or gel containing prostaglandin may be offered if a membrane stretch and sweep is not effective at initiating spontaneous labour. This method of induction is when a tampon shaped pessary or tablet or gel is inserted vaginally in an attempt to ripen the cervix and to stimulate contractions. This is one of the most commonly recommended ways to induce labour.
The artificial rupture of membranes, also known as ARM or breaking the waters, is often used to accelerate labour after other induction methods have initiated contractions or after spontaneous labour has begun. Note: waters do not always break, as is often shown on film and tv, to signify the beginning of labour. Many women reach full dilation before they have a Spontaneous Rupture of Membranes (SROM) with some even birthing the baby in ‘the caul’ (the amniotic sac).
A hormone drip containing synthetic oxytocin (Syntocinon®) should only be offered if the membrane sweep or prostaglandins have not been effective in starting labour. It is also offered to women who may have been induced by membrane sweep or prostaglandins but whose contractions and cervical dilation have slowed completely or appear to have stopped. It is not recommended for use until at least 6 hours after receiving prostaglandin gel or 12 hours after removal of the prostaglandin pessary.
Whether to consent to induction of labour, or not, is a choice that at least 1 out of 3 women will have to make in her maternity care in Ireland. If an induction is clinically indicated, in the case of fetal and maternal risk such as: pre-eclampsia, fetal growth restriction, diabetes or problems with the placenta – then a woman may have less difficulty in agreeing with her maternity care provider that it is in her and her baby’s best interest to undergo an induction to minimise risk. Induction for serious medical conditions can be life saving.
For most other pregnant women, an induction may be suggested because there is a belief that the baby is too big or too small (known respectively as ‘large for dates’ or ‘small for dates’) OR clinical policy states that a woman must be induced after a certain number of days over their 40 week Estimated Due Date (EDD). The consensus on the window of normal gestation is that it can be anywhere from 37 to 42 weeks; however, some hospital policies will suggest induction of labour from 40 weeks, or earlier, depending on the perceived complication. In these cases the research shows that taking a ‘wait and see’ approach more often leads to spontaneous onset of labour, less interventions and a healthy outcome for both mother and baby. The difficulty is knowing when to consent to an induction or when to ‘wait and see’.
The following list of advantages and disadvantages to the various methods of induction of labour may be helpful in balancing the risks and making a choice whether to consent to the procedure, or to ‘wait and see’:
Membrane Stretch and Sweep
- does not involve medication and generally safe when there are no other complications
- if it results in spontaneous labour, it may mean avoiding further interventions with other methods of induction such as oxytocin or prostaglandin
- can be performed at hospital or at home
- some women report pain and discomfort during a sweep
- can cause some bleeding and irregular contractions
- often has to repeated 2 to 3 times before other methods of induction are used
Prostaglandin Pessary or Gel
- increases the likelihood of vaginal birth within 24 hours
- reduces the need for oxytocin augmentation in labour
- risk of uterine hyperstimulation (with the pessary, not with gel)
- may cause changes in fetal heart rate
Artificial Rupture of Membranes
- can be done in hospital or at home
- may shorten labour
- evidence does not support routinely breaking the waters for women in normally progressing spontaneous labour
- there is little evidence that a shorter labour has benefits for the mother or the baby
Hormone Drip with Synthetic Oxytocin
- can shorten labour
- is less likely to cause hyperstimulation than prostaglandins but can be controlled (by reducing the dosage or by switching off the drip altogether) if it does cause lead to tonic contractions
- uterine hyperstimulation leading to much more frequent and painful contractions
- increased rate of other interventions such as electronic fetal monitoring or CTG trace, epidural analgesia, instrumental delivery and c-section
- increased risk of ‘overdosage’ leading to fetal distress
Note: One of the main reasons for an oxytocin drip is slow progression of labour, sometimes referred to as dystocia or ‘failure to progress’. This is controversial as there are no definitive studies that accurately describe the length of ‘normal’ labour. Recent research does not support the original clinical indication for oxytocin augmentation of labour, namely that it was believed the need for operative delivery (either c-section, forceps or ventouse) is reduced by administering oxytocin drip. This is not supported by Cochrane Reviews
Complementary or Natural Methods of Induction include (there is no supported evidence of the following in the medical literature – See Mozurkewich et al.):
- acupuncture and reflexology
- castor oil
- nipple stimulation
- sexual intercourse
If you would like more information on informed decision making or would like to access AIMS Irelands private and confidential support services please see http://www.aimsireland.com or firstname.lastname@example.org If you have a positive induction story you would like to include in our ‘birth stories’ section of 42 weeks, please mail us at email@example.com
The following research links were used to compile the information in this article:
Bugg et al. Oxytocin versus no treatment or delayed treatment for slow progress in the first stage of spontaneous labour. Cochrane Pregnancy and Childbirth Group – Intervention Review. July 6, 2011. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007123.pub2/full
Kelly et al. Vaginal prostaglandin (PGE2 and PGF2a) for induction of labour at term. Cochrane Summaries. May 16, 2012. http://summaries.cochrane.org/CD003101/vaginal-prostaglandin-pge2-and-pgf2a-for-induction-of-labour-at-term
Mozurkewich et al. Methods of induction of labour: Systematic review. BMC Pregnancy and Childbirth 2011, 11:84. http://www.biomedcentral.com/content/pdf/1471-2393-11-84.pdf
National Collaborating Centre for Women’s and Children’s Health. Induction of labour. 2nd edition. London: RCOG Press; 2008. http://www.nice.org.uk/nicemedia/live/12012/41260/41260.pdf
Smyth et al. Amniotomy for shortening spontaneous labour. Cochrane Summaries. June 18, 2013. http://summaries.cochrane.org/CD006167/amniotomy-for-shortening-spontaneous-labour