Induction – Part Two: The Evidence For The Why
This blog post is the second of two parts written with the intention to educate expectant parents about induction, its impact, and the increasing rise of its use in our local hospitals. Induction - Part Two: The Evidence For The Why dexplores the evidence, benefits and risks of medical induction.
Medical indications for artificially inducing labour can include significant maternal disease not responding to treatment, such as pre-eclampsia or other maternal medical conditions that may compromise the mother or baby’s health. Others include infection of the uterus, gestational diabetes, oligohydramnios (too little amniotic fluid for gestational age), and placental abruption. For the fetus, reasons can include not growing well (fetal growth restriction), Down syndrome, or other health complications. The environment may no longer be habitable and the risks to the baby being born outweigh the risks of staying in the womb.
SOME INDICATIONS THAT FALL INTO A GREY AREA:
Going past the estimated due date
Post-term pregnancy and induction of labour resources - Dr Sara Wickham
Evidence on: Inducing for Due Dates
Low amniotic fluid at term
What is the Evidence for Induction for Low Amniotic Fluid in a Healthy Pregnancy?
Amniotic Fluid Volume: too much, too little, or who knows? | MidwifeThinking
Older mother (advanced maternal age)
Not evidence that early induction of labour makes a difference in older women (35/39 trial)
Evidence on: Pregnancy at Age 35 and Older
Suspected big baby
Big Babies: the risk of care provider fear | MidwifeThinking
What is the Evidence for Induction or C-section for a Big Baby?
Often the care provider will recommend induction with well controlled gestational diabetes (GDM) or insulin dependent GDM. If gestational diabetes is well controlled with diet and exercise, and even when insulin is used, the evidence appears contradictory.
Evidence on: Induction for Gestational Diabetes
Additional info regarding universal screening for GDM from Dr Sara Wickham:
Austrian researchers analysed data from nearly a million pregnancies over more than a decade and discovered that universal screening for gestational diabetes has not led to any significant reduction in stillbirths. The reference for this study is: Muin DA, Pfeifer B, Helmer H, et al (2022). Universal gestational diabetes screening and antepartum stillbirth rates in Austria—A population-based study. Acta Obstet Gynecol Scand. 2022: 00: 1– 9. doi: 10.1111/aogs.14334
An aging placenta (risk of stillbirth)
The Myth of the Aging Placenta | Sophie Messager
Additional information about induction based on gestational age:
Women are being led to believe that there is a high chance that their baby will die if they continue with their pregnancy beyond 42 weeks. However, even those studies which appear to show a protective effect of induction before 42 weeks make it clear that the risks of continuing pregnancy beyond this point are extremely low; and the evidence presented in this article does not show that women who are making the decision to continue their pregnancy beyond 42 weeks are encountering increased risk of stillbirth. It also shows that the rate of perinatal mortality is lowest at 42+ weeks. Labour Induction at Term – How great is the risk of refusing it?
Pre labour rupture of membranes at term, (unless mother has developed infection/fever, has GBS, or baby isn’t doing well)
Evidence on: Induction when your Water Breaks at Term
Pre-labour Rupture of Membranes: impatience and risk | MidwifeThinking
RISKS OF INDUCTION:
Induction of Labor and Risk of Postpartum Hemorrhage in Low Risk Parturients
Induction prior to post-term was associated with few beneficial outcomes and several adverse outcomes. This draws attention to possible iatrogenic effects affecting large numbers of low-risk women in contemporary maternity care. According to the World Health Organization, expected benefits from a medical intervention must outweigh potential harms. Hence, our results do not support the widespread use of routine induction prior to post-term (41+0–6 gestational weeks).’ Effects of induction of labor prior to post-term in low-risk... : JBI Evidence Synthesis
Guide to labour induction: What to expect if you're getting induced:
If the prostaglandins work to soften and shorten your cervix (this is often called a “favourable” cervix), your care provider can give you oxytocin through an IV line. Oxytocin is naturally produced by your body to help the uterus contract. It may also be called by its synthetic name, Pitocin. (Oxytocin is generally not used on its own before the cervix is considered favourable because it’s associated with a higher rate of C-sections.) “When you’re given oxytocin, you’re monitored continuously with an external monitor because some people can be quite sensitive to it,” says Dy. “Usually, by that point, you’re having more frequent contractions, every two or three minutes.” Both oxytocin and prostaglandins can reduce your baby’s heart rate, which is also why monitoring is used to make sure that all is well. https://sarahbuckley.com/pitocin-side-effects-part1/
RISKS WITH EPIDURALS
71% had epidurals, compared to 41% who were not induced. C-section rates were more than twice as high – 29% compared to 14% – and episiotomies occurred in 41% of births compared to 31%. Over the 16-year timespan of the data, the rates of induction doubled for first-time mothers at 38 and 40 weeks of gestation. 'No discussion': significant increase in women being induced for low-risk births, study finds | Pregnancy | The Guardian
RISKS OF CESAREAN SECTION
In Vancouver among the local hospitals the 2014/15 Perinatal Health Registry compared outcomes (cesarean or vaginal birth) with rates of induction or spontaneous labour onset. With first time mothers the cesarean birth rate was 47.7% (induction group) compared to 21.5% (spontaneous onset). With a second birth, cesarean rates in the induction group were 14.4% compared to 2.8% with spontaneous onset.
Women whose labour was induced (Robson group 2A) had a CD (cesarean) rate almost double the rate of women with spontaneous labour (Robson group 1): 33.5% versus 18.4%. Examining Cesarean Section Rates in Canada Using the Modified Robson Classification - Journal of Obstetrics and Gynaecology Canada
Data collected recently (June-October 2020) among six local hospitals shows the average cesarean section rate is 43%. Could this partly be due to increasing induction rates? Are inductions that may not be truly medically indicated leading to high cesarean rates? Look at Richmond Hospital and their efforts to reduce inductions, which led to a reduction in cesareans. Might other hospitals apply these measures?
Caesarean section following induction of labour in uncomplicated first births
The implications for health risks with cesarean birth are increased for both mother and baby, as well as for future pregnancies. Babies born by cesarean are at greater risk for numerous health issues including immune disorders, diabetes, arthritis, Celiac disease and inflammatory bowel disease, obesity and respiratory conditions, ie childhood asthma.
As has been pointed out there are valid reasons why an induction would be beneficial either for the mother or her baby. To repeat: when undertaken for appropriate reasons, and by appropriate methods, induction is useful and benefits both mothers and newborns. What isn’t so black and white is how it’s determined that the reason is appropriate.
HOW CAN I LOWER MY CHANCES OF BEING INDUCED UNNECESSARILY?
Find a care provider with a low induction rate. Some care providers have much lower induction rates than others. Although there are exceptions, midwives tend to have lower rates of induction than doctors.
Choose a birth setting with a low induction rate. Some hospitals have far lower rates of induction than others. Some hospitals have quality improvement programs to reduce their induction rates, including programs to avoid scheduling births before the 39 weeks of pregnancy whenever possible. In general, rates of intervention are much lower for out-of-hospital birth centers and at home births compared with hospitals.
Educate yourself about the different reasons women are induced and the evidence supporting these reasons. Consider declining labour induction for reasons that lack good research support or are disproven (informed refusal). For example, induction because the baby may be getting quite large doesn’t improve outcomes and may increase risk.
Do your best to make sure your estimated due date (EDD) is accurate. An EDD is often calculated from the first day of the last menstrual period, which assumes the woman’s menstrual cycle is 28 days long. If your cycles are longer or shorter than 28 days, or if they are irregular in length, tell your care provider. An ultrasound early in pregnancy can provide a more accurate estimate of your EDD. A later ultrasound is not a good way to estimate your due date.
Remember, your estimated due date is based on averages. You will likely go into labour on your own schedule, earlier or later than the predicted date. From childbirthconnection.org
QUESTIONING THE NECESSITY FOR MEDICAL INDUCTION
In Your Own Time - Dr Sara Wickham
This is a newly published book with the most current evidence.
Whether a true medical indication exists that necessitates induction requires a process to engage in, for the expectant parents, to determine what’s right for them. This is ideally done in a shared decision making process with their care provider. The care provider would present their reasoning, based in current evidence informed practice. What also needs to be discussed are the risks of induction, so parents can make a fully informed decision.
What we are seeing today isn’t always this experience for expectant parents. Particularly with situations that fall into the grey areas. When you consider that induction comes with its own risks to both mother and baby, it’s imperative to request current accurate evidence. Ask questions in order to gather information pertinent to the decision making process. Parents can take into consideration their individual situation and possible risk, based in their values, beliefs, intuition and the evidence, to weigh in on the pros/cons to decide how to proceed toward the healthiest and safest birth for both mother and baby.
Debra Woods is a seasoned birth & postpartum doula who’s cared for more than 800 childbearing families. She has been practicing professionally for 32 years. She is also a certified childbirth educator. Mother to one son, who was born at home, she is passionate about educating expectant parents on evidence informed birth. She specializes in supporting couples who believe in birth as a healthy process and desire a physiologic birth, without the use of routine interventions and pain meds.