Giving birth

Induction overload

Why have Canadian induction rates climbed so dramatically? And is it a problem?

By Wendy Haaf
Induction overload


Depending on which statistic you see, anywhere from 21.8 to 44.8 percent of pregnant women in Canada today undergo some kind of intervention intended to kick-start labour.* Either way, two things are clear: A large minority of expectant moms have labour induced artificially, and the practice is much more common today than it was in 1980, when the induction rate was just under 12 percent.

Why is there this huge increase? And are all of these inductions really warranted? After all, induction — like any intervention — carries risks.

The whys behind the rise

There’s no doubt that multiple factors have helped drive the dramatic jump in inductions, starting with an increase in the number of expectant moms who are over 35 or overweight, or have used reproductive technologies to get pregnant — factors increasing the risk of complications that might make early delivery necessary. Maternity unit closures in smaller communities may also have contributed: When women must travel to give birth, they’re more apt to be induced to avoid a long wait far from home.

But perhaps the biggest factor is the increase in induction for postdates (overdue) pregnancy, thanks to studies showing it slightly reduces the already slim chance of stillbirth associated with staying pregnant past 41 weeks (more on that later). Similarly, other research has led to more women being induced when their waters break, before labour starts.

Some experts argue that a shift in caregivers’ attitudes has nudged the numbers upward. “I think the fact that inductions have been shown to be beneficial beyond 41 weeks and an underappreciation of the risks have led some people to extend it into areas where we don’t have any evidence it’s beneficial,” says Michael Kramer, scientific director of the Institute of Human Development, Child and Youth Health, one of the Canadian Institutes of Health Research.
Case in point: “Here in BC, about 30 percent of inductions for postdates are undertaken before 41 weeks,” notes Linda Knox, acting head of midwifery at BC Women’s Hospital and Providence Health Care – St. Paul’s in Vancouver. This conflicts with guidelines from the Society of Obstetricians and Gynaecologists of Canada recommending women be offered induction after 41 weeks. Another example of how caregivers’ opinions have raised rates: In practice, some physicians treat induction for postdates at 41 weeks as a policy, not a choice.

In short, what seems to have happened is that as induction has become more common, caregivers and women alike have become more comfortable with it, and thus more inclined to induce — sometimes even in situations where there’s no evidence induction is any safer (or even as safe as) waiting for labour to start on its own.

Now you know why your chances of being induced are greater than your mom’s might have been. But how do you weigh your options if your caregiver suggests stepping in to get labour started? Here’s what you need to know, starting with the reasons induction might be suggested.

* Both figures come from the Public Health Agency of Canada: The former is based on hospital data; the latter on a survey of 6,000 new moms. It’s thought the latter number is larger because it may include non-medical measures to get labour going.


As you might imagine, induction is recommended when there’s reason to think mother and baby would be better off apart. Here are the most common indications, roughly from strongest to weakest:

• Most caregivers agree it’s clearly best to induce when a mother develops dangerously high blood pressure or pre-eclampsia; if the placenta isn’t functioning properly; or if a baby shows signs that continuation of the pregnancy is dangerous.

• When the bag of waters breaks before labour starts, infection becomes a possibility. Induction to deliver the baby (after 37 weeks) reduces the risk of infection in the mother. However, it’s not clear that this needs to be done right away; some caregivers will take a wait-and-see approach for at least 12 hours to give labour a chance to start on its own.

• There is good evidence that induction is sometimes helpful when a woman goes overdue, but the benefits are modest. According to one estimate, inducing at 41 weeks only cuts the odds of stillbirth from two in 1,000 to one in 1,000 — in other words, 1,000 women must be induced to prevent one stillbirth. Because large epidemiological studies only tell us what the consequences of induction are for large groups, not for individual women, doctors differ on what to do with this information. “The debate continues to rage over whether you should induce for postdates at 41½ weeks or try to individualize care to make sure the mother’s cervix and the baby are both ready,” explains Michael Klein, a senior scientist and maternity researcher at the University of British Columbia and the Child & Family Health Research Institute in Vancouver.

• Very slow fetal growth is considered a compelling indication, but this may change in light of a recent study in which growth-restricted babies did just as well when they stayed put until labour began naturally.

• Many caregivers also advocate inducing women with gestational diabetes after 38 weeks, though there’s scant evidence it offers any advantages for babies or moms.

• Research clearly does not support inducing when a baby is suspected to be large: It doesn’t prevent C-sections, nor does it improve newborn outcomes.


Like any other intervention, induction has risks, which must be balanced against the hoped-for benefits. And while the decision is a no-brainer if your soaring blood pressure is endangering your life and your baby’s, the choice isn’t so clear-cut if you’re a few days or even a week or two overdue.

First of all, while induction is considered safe, it’s been associated with some uncommon problems, such as uterine rupture in moms who’ve had a previous C-section, and close-together contractions that reduce baby’s oxygen supply. Drugs that trigger contractions may somewhat reduce the odds of breastfeeding success. And if your dates are off, your baby might be born before 39 weeks’ gestation. These “slightly premature” babies do have an increased risk of breathing difficulties and other health problems.

There’s also some evidence that induced labours may be longer and more painful, especially if the cervix is not ready. Certainly more women who are induced end up with epidurals. And, finally, several studies have found that induced women are more likely to have Caesareans, which carry their own risks, including a higher likelihood of placenta-attachment problems and stillbirth in future pregnancies, says Klein. Knox concurs: “Induction is associated with a 30 percent increase in the likelihood of C-section,” she says. (And the increase is even greater for first-time moms.)

Making the call

Obviously, the risks and benefits of induction differ depending on the situation, so you’ll need personalized information to make the decision that’s right for you. And the best way to get it is to ask lots of questions. Here are some suggestions to get you started.

• If there is a problem, how serious is it? How urgent is it that we induce?
• How likely is an induction to be successful?
• Can you describe the procedure? If it doesn’t work, what are the next steps?
• What are the risks involved?
• Are there any alternatives, including waiting or not inducing? What are the risks of these alternatives?
• What happens if I choose not to take your recommendation? (Unfortunately, some caregivers may ask you to find another provider.)

The decision you make will depend in part on your values and how much weight you place on a particular risk or benefit. For instance, if you’re concerned about how a C-section could affect your plans to have a large family, you might be more inclined to play the waiting game.

Going ahead

Let’s suppose you’ve decided to go ahead with induction. What can maximize your chances of success and help the process go as smoothly as possible?

Prepare the cervix “An induction is less likely to be successful if the cervix is closed, and posterior, and not effaced (thinned),” says Gisela Becker, president of the Canadian Association of Midwives. Ask your caregiver to assess your cervix. If it’s not “ripe,” one of two methods can be used to help coax it open: inserting a small balloon called a Foley catheter between the uterus and the bag of waters, or applying the hormone prostaglandin. The balloon is safest for women who’ve had a prior C-section; it can also be removed if, say, contractions start coming on too hard and fast.Schedule for a.m. Knox says there’s some evidence that inductions started in the morning are more likely to be successful than those begun in the evening, so if there’s no reason for urgency, ask for an a.m. booking. Plus, you’ll be going in rested, which will help you cope.

Postdates possibilities

Let’s assume your caregiver has suggested induction because you’re overdue, and you’d like to explore alternatives before agreeing. What can you do?

Review your dates “If women have a first-trimester ultrasound, they’re much likelier to have accurate dating,” observes Knox, but other factors can still throw off the estimate. Are you certain the date you gave for your last period was accurate? Or maybe you forgot to mention your cycle is 34 days long, rather than 28.

Consider surveillance Keeping tabs on the baby with kick counts, periodic ultrasounds and twice-weekly non-stress tests doesn’t completely eliminate the risk of postdates-related stillbirth, “but mitigates it,” says Andrew Kotaska, a researcher and clinical director of obstetrics and gynaecology at Stanton Territorial Hospital in Yellowknife, NWT. This strategy also reduces the odds of C-section for failed induction, and breathing problems in the baby due to inadvertent early delivery, adds Klein. “We are simply asking the fetus how he’s doing in there.”

Ask about membrane sweeping A procedure in which a caregiver inserts a gloved finger into the cervix and gently separates the amniotic bag from the uterus, membrane sweeping causes a release of prostaglandin, the hormone that softens the cervix and may give labour a nudge.

Try acupuncture While it hasn’t been well studied, some women find that acupuncture gets labour moving, Knox notes.

Delay a few days Just waiting until 41 weeks plus three days increases the chance you’ll go into labour on your own.

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This article was originally published on Aug 03, 2010

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