Midwives have hit back at research saying doctor-led births are less risky, saying birth is safe in this country but services are under pressure and urgently need more funding.
The Otago University researchers said it was the first detailed study examining the effect - if any - of the change by New Zealand in 1990 from GP-led maternity care to an autonomous, midwife-led model.
College of Midwives chief executive Karen Guilliland said the main finding of the research was down to a lack of adequate funding for midwifery and its back-up in hospitals.
"We're actually safer and better now today than we've ever been in the history of New Zealand maternity services. What we're saying is we can't maintain that if we're not better organised, funded, so that all women have equitable access to the secondary care that they need when they need it."
She said the differences highlighted by the research might be explained by the way maternity system operated.
"Most of our maternity hospitals are under-staffed and often struggle to provide immediate response when midwives request medical input. This means that often women in labour have to wait to see a specialist, causing unacceptable delays for them and their babies.
"None of our main maternity hospitals have an obstetric consultant on site after hours or weekends which are when the majority of births occur."
Midwives also pointed out the study reported no difference in deaths of mother or babies whether the lead maternity carer (LMC) was an obstetrician or GP, or a midwife.
"However, it suggests morbidity for the baby (being unwell) immediately following the birth is more prevalent in cases where the LMC is a midwife, although no different to other similar countries."
Pat Tuohy, the Health Ministry's chief advisor for child and youth health, said it was taking the findings seriously and had referred them to the National Maternity Monitoring Group.
Dr Tuohy said the Ministry wanted the group to look into the midwives' claim of a lack of timely access to a specialist when they made a referral.
He said the research did not answer why different results might occur, according to who was the lead maternity carer. The individual who was actually providing care during delivery of a baby could also differ from who was the registered LMC.
He said the researchers had "done as good a study as they can given the data available to them".
"I think the most important thing for us to point out from the Ministry perspective is that we have a safe and effecitve system for maternity care for women and babies. However, this study is a useful study from the point of view of shining a light on where we may be able to look at improvements."