Late term pregnancy
Defining a Prolonged Pregnancy
Term pregnancy: 37-42 weeks
Post-dates: Beyond 40 weeks
Post-term: 42+ weeks
Around weeks 39-40 care providers will often discuss with pregnant women and people both induction of labour and expectant management along with the associated benefits and risks.
Genetic and nutritional factors may influence gestation length, and babies play a key role in initiating labour when ready.
Induction of labour has become widespread in medicalised maternity care, significantly changing the duration of pregnancy.
In Australia, most babies are now born before their estimated due date, with very few pregnancies reaching 42+ weeks.
Many inductions are not for 'prolonged pregnancy' but for other reasons such as maternal age, BMI, or gestational diabetes.
It’s important to note that modern maternity systems impose rigid, non-evidence-based timeframes for birth, leading to interventions, including c-sections.
Induction allows care providers to start and/or augment labour for a range of reasons for which it is the hospital’s or care provider’s responsibility to adequately inform of reasons, risks and benefits and ultimately the parent’s choice to decide if they agree and would like to consent.
Hospitals are well-equipped to manage the process of induction as well as any of the complications that may arise.
General Information
The Great Birth Rebellion / Episode 33 - Induction of Labour
Risks of Induction of Labour
Interventions: When labour does not begin spontaneously the likelihood of further interventions is greatly increased, this is often referred to as the cascade of interventions; interventions include the way in which monitoring occurs, the need for IV’s, catheters, assisted birth and c-section to name a few.
Medicated pain relief: This is not an issue for everyone, but some people wish to avoid this. The contraction intensity and pattern of labour that is medically induced is different to spontaneous labour in that the synthetic hormone does not talk to the brain and contribute to the overall hormonal changes and actions of spontaneous labour, the contraction pattern is more intense sooner and there is generally less rest between contractions. This may not be true for everyone, as everyone will respond differently to the medications and procedures.
Fetal distress: When labour begins with the assistance if inductions and/or medications a number of these have increased fetal distress listed as a potential risk.
Instrumental Vaginal Delivery: Induction of labour has been associated with a higher likelihood of requiring instrumental assistance during delivery, such as the use of forceps or vacuum extraction.
Uterine Hyperstimulation: The use of induction agents can lead to excessive uterine contractions, which may cause fetal distress and necessitate emergency interventions.
Babies experience of labour: Babies may not have physically completed their preparation for birth as well as the pattern and intensity of induction is more likely to cause fetal distress.
Maternal Discomfort and Longer Hospital Stay: Induction may result in a longer and more painful labour process, potentially leading to extended hospitalisation.
Breastfeeding Challenges: Some research suggests that induced labour may be linked to lower rates of early breastfeeding success due to potential impacts on neonatal readiness and maternal hormonal responses.
Neonatal Intensive Care Unit (NICU) Admissions: Induced babies, particularly those born at 39-40 weeks, may have a slightly higher chance of requiring NICU care due to respiratory distress or feeding difficulties.
Emotional and Psychological Impact: Induction of labour may contribute to feelings of loss of control, increased anxiety, and dissatisfaction with the birth experience, particularly if expectations are not met.
Failed Induction: Inductions may not always lead to vaginal birth, increasing the likelihood of emergency caesarean section, especially in first-time mothers.
Umbilical Cord Issues: Artificial rupture of membranes (if part of the induction process) can sometimes lead to cord prolapse, which may require emergency intervention.
Longer Labour for First-Time Mothers: Induction may result in a longer and more physically exhausting labour, particularly for those who have not given birth before.
The Great Birth Rebellion Podcast: Part 1 Part 2
Benefits of Induction of Labour
Perinatal Mortality: Inducing labour at or beyond 41 weeks has been associated with a decrease in perinatal deaths. See info in Risks of Expectant Management for the detail on stillbirth below. The risk of stillbirth increases as pregnancy progresses, but understanding absolute risk vs. relative risk is crucial.
Absolute risk refers to the actual chance of an event occurring. For example, at 41 weeks, the absolute risk of stillbirth is 1.7 per 1,000 births, increasing to 3.2 per 1,000 at 42 weeks.
Relative risk compares risks between two groups. A 94% increase in stillbirth risk from 41 to 42 weeks sounds significant, but the actual numbers remain low (1.7 vs. 3.2 per 1,000).
The way stillbirth rates are measured also affects reported figures. Understanding these differences helps ensure clear and accurate discussions about risks. Article / Research
Meconium Aspiration Syndrome: Induction is linked to a reduced risk of the fetus inhaling meconium-stained amniotic fluid, which can cause respiratory complications.
Perineal Trauma: Some studies suggest that well-managed induction in some cases might reduce severe perineal trauma compared to emergency caesarean or instrumental births following prolonged labour.
Caesarean Section: In some studies, induction of labour has been associated with a lower risk of caesarean delivery compared to expectant management. This research compares induction to expectant management in mixed risk populations. More rigorous research challenges this claim. A 2019 review found that inducing labour at 41 weeks, compared to waiting until 42 weeks, was actually linked to a higher risk of c-section. The impact of induction on c-section rates also varies depending on whether it is a woman’s first labour or a subsequent birth, with first-time mothers generally facing a higher risk.
Maternal Anxiety in Some Cases: For women with anxiety about prolonged pregnancy or a history of traumatic birth, planned induction may offer a sense of control and predictability.
Improved Access to Support: Inductions allow parents to plan their birth, ensuring that preferred birth companions, doulas, or healthcare providers are available.
Risks of Expectant Management
Ageing placenta: While placental changes occur, they are likely physiological rather than harmful or indicating a failure on the placenta’s behalf. Article
“Big baby”: Babies grow bigger the longer they gestate, but research suggests interventions due to size concerns contribute more to complications than the baby’s actual size. Article
Meconium-stained fluid: As the pregnancy progresses and the baby’s bowels mature it is more likely that they will pass meconium before and during birth but this is not necessarily problematic. The main concern is Meconium Aspiration Syndrome which can lead to respiratory issues and infection though the risk of this is low; there is a bigger clinical picture that needs to be drawn including how thin or thick the meconium is for example, not all cases pose the same levels of risk. Article
Perinatal Mortality: Continuing the pregnancy beyond 41 weeks is associated with a higher risk of stillbirth and neonatal death, the data needs to be looked at in detail and specific to the profile of the mother and scenario and so the research on whether induction reduces stillbirth is inconculsive. See above the detailed stillbirth information in the Induction Benefits section.
Increased Maternal Morbidity: According to 3 studies by Caughey et al. done in 1992-2002 suggested that extended pregnancies may lead to complications such as infection, placental abruption, postpartum hemorrhage, pre-eclampsia, 3/4th degree tears and the need for operative deliveries. The study provides insight for potential risk but it is limited by its retrospective design, population specificity, lack of control for intervention rates, and potential confounding variables, making its findings less able to be generalisable to different populations.
Benefits of Expectant Management
It goes without saying that all of the risks of induction of labour are decreased in expectant management.
This includes:
Lower risk of medical interventions
Increased likelihood of natural pain management
Reduced risk of fetal distress
Reduced risk of instrumental birth
Lower risk of uterine hyperstimulation
Higher likelihood that baby is ready to be born and transition well
Less likely to stay in hospital for longer
Lower risk of Special Care or NICU admission
Greater emotional and psychological wellbeing
Increased Likelihood of Spontaneous Labour: Allowing the pregnancy to progress naturally increases the chance of labour initiating without medical intervention ensuring the benefits of the physiological and hormonal processes that support bonding and healing for mother and baby.
Avoidance of Induction-Related Complications: By not inducing labour, the risks associated with induction agents, such as uterine hyperstimulation, are avoided.
Higher likelihood Improved Maternal Satisfaction: Some women prefer to await spontaneous labour, which can lead to a more positive birth experience.
Questions for Your Care Providers
These questions help you gather information about your specific clinical situation and weigh the risks and benefits of different options as they are relevant for you.
Understanding the Recommendation
Why are you recommending induction in my case? Is this based on guidelines, policy, or my unique medical situation?
Are there any alternative options to induction for my specific circumstances?
What are the actual risks of continuing my pregnancy vs. inducing labour at this stage? Can you provide absolute risk numbers rather than just percentages?
If I wait for spontaneous labour, what monitoring or tests would you recommend, and how frequently?
Evaluating the Risks & Benefits
What are the potential risks of induction for me and my baby?
How does induction change my likelihood of needing additional interventions (epidural, instrumental birth, caesarean, postpartum haemorrhage)?
How does induction impact the baby’s experience of labour? Are there any increased risks of fetal distress, NICU admission, or breathing difficulties?
What are the short and long term effects of inducing labour before my baby initiates it naturally?
Understanding the Induction Process
What method(s) of induction would you recommend for me (e.g., prostaglandin gel, balloon catheter, artificial rupture of membranes, syntocinon drip)?
If the induction process starts but my body isn’t responding well, what are my options? Can I stop the induction and reassess, or will it lead to further interventions?
How will my ability to move, eat, and use pain relief options be affected by induction?
Informed Consent & Decision-Making
What happens if I decline induction and choose to wait for spontaneous labour? What additional monitoring would be recommended and when?
Can you walk me through the statistics for perinatal mortality and complications for my specific situation, rather than general population data?
Can I take time to think about this decision, or do I need to decide immediately?
If I decide to proceed with induction, how can I maintain as much control and comfort as possible during the process?
