Christchurch mum Vanilla Tillman had to call 15 midwives before finding one to help deliver her son Archie. She wasn't happy with her care, and has continuing injuries from childbirth. But she didn't get a choice.

We're told New Zealand has world-class maternity care. A widely-cited 2016 review, for example, points to midwifery-led care as the ideal model.

But analysis by Stuff indicates improvements in outcomes for mothers and babies have stalled. In some measures, we are faring worse.

Today, Stuff launches an open-ended investigation into maternity care. We will return to this topic throughout 2018, with particular focus on maternal mental health; equity of access; systemic problems such as workforce, complaints procedures, and malpractice; and postnatal care.

READ MORE: Hospital overcrowding puts most vulnerable babies at risk

One of the best ways of measuring a system is by looking at the worst possible outcomes. While babies who might formerly have been stillborn are now being kept alive more frequently, our newborn death rate has stagnated. Meanwhile, other developed countries, such as Australia and the United Kingdom, are saving more babies.

In 2015, the most recent year for which data is available, there were 578 perinatal deaths, which means the period from 20 weeks gestation to 28 days old and includes stillborn and fetal deaths.

This is the lowest number on record. But in a quarter of these deaths, issues around care — including its organisation and management, barriers to access, and staffing – contributed to the death. One in seven deaths could have been avoided.

Other babies survive, but with permanent damage. Throughout this series we will tell the stories of mothers, such as Helen Johnson of Wellington, who is still fighting to find out why Hutt Hospital did not have the right staff or equipment to stop her daughter Piper's brain bleed, which she believes was preventable.

Of our mothers who get seriously sick or hurt during childbirth, 40 per cent could have been avoided with better, more timely care. Others struggle to get recognition for birth injuries, or funded for ACC treatment, like new mum Vanilla Tillman, from Christchurch.

Our maternal suicide rate is seven times higher than the United Kingdom. Māori mothers are three times more likely to take their own lives than Pākehā. Many more struggle for mental health support, like Hawke's Bay's Kelsie Moroney.

The 2017 budget allocated $155 million to maternity funding, up from $137m in 2008. But when adjusted for inflation, maternity funding actually decreased by $3m during that time.

In the main, giving birth in New Zealand is safe. The vast majority of women will have an uneventful pregnancy, with the end result a healthy baby. The chances of dying in childbirth are 15.6 in 100,000, and the chance of a baby dying past 20 weeks gestation is 9.7 in 1000. This is a tiny percentage of the 60,000-odd births in this country every year.

But every death is a tragedy, and the worst-case scenarios are not the only way we evaluate whether women get the best possible care. The Ministry of Health also counts other things, such as how much damage is done to the vagina during birth, and the number of low-risk women who undergo c-sections.

In both of these measures, we are getting worse. In its last report, the National Maternity Monitoring Group itself questioned why there had been little positive change over 21 outcomes for women in six years.

"One of the feelings we have is that maternity always appears to be at the bottom of the heap, and the only time District Health Boards really get worried about maternity services is when they hit the front page of the paper," the group's chair Dr John Tait told Stuff.

"It's only when we hit crisis point – like we're having a crisis point at the moment – that we can get some sort of impetus that things have to change."

We are failing our most vulnerable. Māori, Pasifika, and Indian women fare worse across almost every measure. Young Māori women in particular are less likely to attend antenatal classes or breastfeed past two weeks, and are more likely to have premature babies and mental health issues.

And where you live matters, with rural women and those in poverty less likely to be able to access care.

Maternity care is an emotive topic, and a hotly-contested political space. Over the course of this investigation, we have spoken to dozens of hardworking medical professionals including midwives, obstetricians, researchers, nurses, GPs,neonatologists, psychologists, social workers, physiotherapists and pediatricians.

We have heard stories from women from Kaitaia to Gisborne, Wellington to Wanaka. We heard from Rotorua mum Ana Phillips, still recovering from a third degree vaginal tear which she endured without the epidural she wanted. We spoke to Ashleigh, from Napier, who suffered post traumatic stress after the birth of her son. We also talked to women who had excellent care, and whose lives and those of their babies were saved.

JOHN COWPLAND Ashleigh says she did not receive enough support to deal with the traumatic birth of her son Alistair, 18 months.

This series asks: is the current system working for women and their babies? Do all women receive good quality maternity care, and do all women have equal access to it — regardless of where they live, or their ethnicity? If not, why?

Our interviews have revealed deep concern for women's health and a prevailing sense that maternity care is at breaking point.

Graphs by Andy Fyers.