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‘No discussion’: significant increase in women being induced for low-risk births, study finds

When Emma, a 30-year-old lawyer from Perth, was 30 weeks’ pregnant with her first child, she was told by her doctor that the baby had a big head.

This, the obstetrician told her, put her at risk of complications during birth, with the potential for the baby to get stuck in the birth canal if the pregnancy progressed to 40 weeks.

Though Emma, who would prefer not to disclose her full name, had wanted to go into labour spontaneously, she felt pressured into agreeing to have her birth medically induced. Her doctor booked her in for an induction just after she reached the 38-week mark.

“It wasn’t even a discussion, it was: ‘this is what’s happening,’” she says. “It’s really, really hard to disagree with doctors or people in positions of authority – and in particular when you’re in such a vulnerable position.”

Inductions are more painful than natural labour, and the birth was a traumatic experience for her. After the labour failed to progress for several hours, her baby appeared to be in medical distress, and she was taken into theatre for an emergency caesarean section.

Her son was born at 3.8kg – slightly above average weight.

An induction of labour occurs either surgically or with prescribed medication, as opposed to spontaneously. Inductions are often medically necessary, most commonly when the the baby is overdue – beyond 41 weeks – but also for women with underlying medical conditions such as diabetes.

But a new study of births in New South Wales between 2001 and 2016 has found a significant rise in the number of women being induced for low-risk births, when there is no apparent medical reason.

The study, published in the journal BMJ Open, included 474,652 women aged between 20 and 35 who had uncomplicated births, and where the baby’s gestational age was between 37 and 41 weeks.

It found that 15% of these young, healthy women had an induced labour without a recorded medical indication.

The study also found far higher rates of medical intervention for new mothers who were induced, which is listed as a risk of induction by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists. 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.

Lead author Professor Hannah Dahlen of Western Sydney University says the most troubling finding was that the rate of inductions among first-time mothers at 37 weeks had tripled.

“Why that worries us is because those babies potentially could have another three weeks in the mother’s uterus,” Dahlen, a midwifery expert, says. “Those three weeks that they miss out on in their mother’s uterus is actually really critical for brain development.”

She points to studies showing that babies born at 37 or 38 weeks – known as “early term” births – have higher rates of development delay and lower cognitive outcomes than infants born at term (39 or 40 weeks).

Infants from induced births in the study were also more likely to be later admitted to hospitals for respiratory and ear, nose and throat infections.

According to World Health Organization guidelines: “Induction of labour is not recommended in women with an uncomplicated pregnancy at gestational age less than 41 weeks.”

Although full term is considered to be 39 to 40 weeks, how long a woman’s pregnancy lasts varies naturally, Timothy Moss, an associate professor at Monash University who was not involved in the study, says. “37 weeks will be right for one person and 41 weeks might be right for another,” he says.

Research has found black and south Asian women, for example, have a shorter average pregnancy length before spontaneous labour than white European women, delivering on average at 39 weeks compared to 40.

“There’s no doubt that medical intervention in labour and the involvement of doctors in care during pregnancy in some cases is necessary,” Moss says. “Throughout history it’s certainly saved thousands, millions of lives.”

But, he says, evidence also shows healthy women with low-risk pregnancies can safely deliver babies without unnecessary medical intervention.

“They’re capable of doing that with very good outcomes in terms of their babies, in terms of their bodies, but also in terms of their mental wellbeing.”

Australian researchers led a 2018 review of studies on low-risk births and found no statistically significant difference in infant mortality rates whether the baby was born at hospital, at home, or in a birth centre.

Dr Alex Polyakov, an obstetrician and senior clinical lecturer at the University of Melbourne, takes issue with the methods used in the NSW study.

Because the study looks at historical data, he believes outcomes can’t be compared between a woman who is induced at a given length of pregnancy and a woman who spontaneously delivers in the same week.

He points to a well-regarded 2018 study, known as the ARRIVE study, in which 3,000 women were randomly assigned to be induced, and another 3,000 had spontaneous births.

It found that inducing first-time mothers who had low-risk pregnancies at 39 weeks was associated with a lower rate of caesarean sections – 19% compared to 22% of mothers who were not induced.

ARRIVE was a randomised controlled trial – considered the most reliable form of scientific evidence because it can demonstrate that the treatment results in an effect on human health. Observational studies – like the NSW one – can show that a particular intervention and outcome are linked, but not definitively that one causes the other.

For many clinicians, the ARRIVE study is evidence that women can be induced at 39 weeks without significant adverse effects.

“We just don’t induce women at 37 weeks for no reason,” Polyakov says. “We wouldn’t induce women at 38 weeks for no reason.”

One outcome the NSW study was unable to look at was stillbirths, which occur in Australia at a rate of 7 in every 1,000 births.

The rise in inductions of first-time mothers around 40 weeks might be the result of doctors erring on the side of caution when considering the possibility of preventable stillbirths, Moss says.

“I don’t think there is ever any sinister intent on the part of midwives or obstetricians who might step in and do something that they think is really necessary, perhaps to save a mother or a baby’s life,” he says.

“As time goes on, the rate of stillbirth actually increases because the placenta has a use-by date. It functions to a certain point, and usually labour sets in before that point,” Polyakov says. “The placenta can fail anytime – the chances are low, but it can happen.”

US data puts the risk of stillbirth as increasing from 2.1 in every 10,000 births at 37 weeks to 10.8 in 10,000 births at 42 weeks.

“From my point of view, having an epidural is not a negative outcome, having a caesarean is not a negative outcome,” Polyakov says. “A negative outcome is a stillbirth, a negative outcome is a distressed baby who needs an emergency caesarean.”

The rise in early-term inductions in first-time mothers, believes Dahlen, may be partially attributable to an increasing push for efficiency in healthcare.

“Childbirth, like so much of health, is turned into an industry,” Dahlen says. “You get people in, you get people out.” Scheduling inductions, she says, may be a means to make the process of birth more efficient and predictable.

Previous research of Dahlen’s has found low-risk women giving birth in private hospitals in NSW were far more likely to experience interventions during labour, and 20 cent less likely to deliver their first child through regular vaginal birth.

But, Polyakov says, in the public hospital system doctors have no financial incentives to offer inductions, because they are more costly and resource-intensive than spontaneous births. “Once you induce someone you have to keep them in hospital until they deliver,” he says.

“We don’t do inductions because they are convenient for us,” Polyakov says. “As an obstetrician, I want an outcome that is a healthy mother and healthy baby.”

Moss emphasises that the findings of the NSW study can only be applied to women with low-risk pregnancies.

Of 1.5m births in total in NSW over the study period, two-thirds were excluded from the study because the mothers had risk factors such as underlying medical conditions.

“What this study shows is that the majority of pregnancies in this NSW dataset were not as uncomplicated and straightforward as they could be,” Moss says.

Obstetric practice has changed in the last decade, says Polyakov. “There are more women who have medical problems, there are more women who are overweight, there are more women who have gestational diabetes, and hypertensive disorders.”

As a result, he says, the number of women who do have medical indications for induction has likely also increased too.

Abbey McCauley, a 33-year-old Melbourne woman, has had three medically-necessary inductions for her pregnancies. With her first child, she was suspected of having cholestasis of pregnancy, a condition associated with intense itching. Pelvic instability and gestational diabetes were diagnosed for the second and third. “I felt a lot less stressed knowing that I was being induced,” she says. “It definitely put my mind at ease.”

Emma delivered her second child last year, as a vaginal birth after caesarean. Compared with her first birth, she felt supported in the process by an experienced obstetrician, as well as a doula and student midwife. “If it had ended in a C-section, I would have felt just as fine with it,” she says.

There is a lasting frustration that her first obstetrician hadn’t fully informed her about the potential consequences of an induction.

“At the end of the day, it should be the patient’s decision, and the patient can’t make that decision properly unless they have been given all of the information,” she says.

To other pregnant women, she offers the following advice: “Do your research, figure out what your preferences are, then surround yourself with people who support you and your decisions about your body.”

 

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