‘Striking’ report reveals rise in birth interventions among low-risk mums

Rising numbers of first-time mothers with low-risk pregnancies are experiencing a “cascade” of birth interventions, from inductions to caesarean sections, analysis of more than 343,000 births in NSW reveals.

More than one in four women (25.6 per cent) giving birth to their first child in 2018 and deemed to be low-risk experienced a labour induction or augmentation, followed by an epidural, then an instrumental birth or unscheduled caesarean section, with each intervention making the next more likely.

This was more than double the 11.4 per cent of women who underwent this cascade of interventions in 2004, raising questions about whether they are medically necessary and leaving mothers traumatised by unexpected procedures.

The study by University of NSW and University of Technology Sydney researchers published in the journal Health Economics and Policy , said women considered low-risk had no pregnancy complications, a gestation of at least 37 weeks, and a baby in the head-down position.

The study excluded women whose strong birth preferences meant they had either planned caesareans or gave birth in low-intervention birth centres.

These preferences also grew over the time period. In 2004, 2.8 per cent of low-risk women who had never given birth chose to deliver in a birth centre, a cohort which almost doubled to 5.4 per cent by 2018. Elective caesareans also rose in the same cohort, from 5.9 per cent in 2004 to 9.1 per cent in 2018.

Researchers found the rates of cascading interventions among low-risk women almost matched those of high-risk women, and that an increase in the practice was closely related to a decline in natural vaginal births.

“The results were very striking,” said lead author and UNSW Professor of Economics Denzil Fiebig.

“To have so many women across such a long period of time across all hospitals … it’s not well documented and not well understood.”

The report noted vast differences in intervention across the 56 hospitals, leading researchers to conclude that cascading at each institution was a major driver.

“This may be about risk aversion and management,” co-author Serena Yu, an associate professor in health economics at UTS, said.

“It’s not malicious – if you induce a woman and put her down that path, you have more control over the timing and ability to monitor what’s happening to her and the baby, compared to letting her labour, and leaving more question marks over what happens, particularly the possibility of an adverse event.”

For Alicia Woodfield, a cascade of interventions during the birth of her first child left her “traumatised”.

The Lake Illawarra resident had dreamt of a natural birth, but agreed to an induction when she had not gone into labour by just under 41 weeks’ gestation.