Major New Zealand midwifery research into 16,000-plus low-risk women’s births has found “astounding results”. The more high-tech the hospital is you plan to give birth in, the more likely you are to end up with an emergency caesarean and a baby in neonatal intensive care.
FIONA CASSIE talks to lead researcher Deborah Davis about the Birthplace NZ research.
It’s a given that every mother-to-be and midwife wants the best possible birth outcome for mother and baby.
So does where you plan to give birth make a difference?
The Birthplace New Zealand research team set out to find what impact a woman’s choice of birthplace had on birth outcomes.
The retrospective analysis of 16,453 births by low-risk women under midwifery care came up with “astounding results”, says lead researcher Dr Deborah Davis.
What researchers had expected was an increased use of pharmacological pain relief by low-risk women choosing to birth in secondary and tertiary hospitals compared to women choosing home and primary care settings.
But what they did not expect was choice of birthplace would have “such a profound difference” on the likelihood of women having a normal physiological birth.
Choosing to birth in a high-tech environment appears to increase the risk of women having an emergency caesarean section and their babies ending up in neonatal intensive care.
Davis, formerly at Otago Polytechnic’s school of midwifery, was lead researcher for the project which included other midwifery academics from Otago Polytechnic, Massey University, AUT and CPIT.
She says what makes the New Zealand study different from other international studies was it was the first one where all the women were under the same model of care – midwifery-led care – and all were low-risk.
The study drew from the Midwifery Maternity Provider Organisation (MMPO) database for births in 2006 to 2007 – which held data for nearly 40,000 births – about a third of the total national births for those years.
The researchers then went through and excluded from their study all women regarded as high-risk (see sidebar on the next page), leaving them a cohort of more than 16,000 births.
Just less than a third of those woman planned to give birth at home or in a primary care unit, while just over 70 per cent planned to give birth in a secondary or tertiary hospital. The data was anonymous, so it was not known where the women lived or what birthplace choices were available to them.
It was expected that different motivation levels would impact on the use of pharmacological pain relief, like epidurals, between women wanting to birth at home and those seeking a tertiary hospital, but Davis says motivation cannot explain the difference in caesarean levels.
The study found planning to give birth in a secondary or tertiary setting saw the risk of intervention rise incrementally. The risks were highest for women planning to give birth in a tertiary hospital – who despite having the same low-risk profile as the women planning a primary unit birth – had 6.1 times the risk of ventouse, 5.4 times the risk of forceps and 4.6 times the risk of an emergency caesarean.
So while around 95 per cent of the home or primary unit birth women had a normal vaginal birth, only 73 per cent of the women planning tertiary hospital births did.
Davis says her own PhD research – which involved intervewing case-loading midwives about their experiences of working in tertiary hospitals – indicated midwives found it difficult to promote normal birth in a tertiary setting.
“I did expect there would be a difference but I was pretty astounded by the degree of difference.”
Other qualitative studies also indicate midwives feel their practice is affected by place. Another possible hypothesis is anxiety levels in women in labour are raised by being in a high-tech environment, causing physiological responses prolonging labour and raising risks of foetal distress.
Babies of women planning to give birth in the secondary or tertiary settings also had an increased risk of being admitted to neonatal intensive care (1.4 times the risk for secondary and 1.8 times the risk for tertiary hospital). But mothers’ choices of where to birth made no statistical difference to the newborn physical assessment rates (babies getting five minute Agpar scores of less than seven) of their babies.
Davis says the increased neonatal admissions from low-risk women at tertiary hospitals was also unexpected and could only surmise it was because a unit was available and babies were sent “just in case” – or the higher level of interventions like caesarean or ventouse meant more babies needed to go to neonatal units.
Davis, who is now based at the University of Technology, Sydney’s Centre for Midwifery, Child and Family Health, believes the research is really relevant to policy makers.
She says interventions in labour and birth came at increased risk to baby and mother and also in financial costs. “There’s a great cost involved in not having a normal vaginal birth.”
The study’s findings have been presented this year at the Perinatal Society of Australia and New Zealand’s conference plus several midwifery conferences and she is keen for it to be published to get a wider audience than midwives. “I really hope that obstetricians and policy makers will hear this.”