A nursing expert has told a coronial inquest that Naomi Williams – a 27-year-old Wiradjuri woman who was six months’ pregnant when she died in 2016 from a treatable infection – should have been monitored for at least four hours.

In the early hours of New Year’s Day 2016, Williams presented to the emergency department of Tumut hospital with pain. Nurses allowed her to go home after 34 minutes with two paracetamol and no assessment from a doctor.

Williams, a Naidoc award-winning disability caseworker, had presented to hospital 18 times in the six months before her death with severe pain and vomiting, and her GP had identified her pregnancy as high-risk.

After being discharged, her condition worsened and 15 hours later she died from sepsis associated with the bacterium Neisseria meningitidis, a serious infection that is treatable with antibiotics.

On Wednesday in Sydney, two expert nurses told a coronial investigation – which began last year in Gundagai under deputy state coroner Harriet Grahame – that Williams should have been monitored for longer and should have been seen by a doctor.

Jasmine Douglas and Eunice Gribbin told the inquest that “any pregnant woman who arrives in emergency with those kinds of symptoms” should have seen a doctor before being sent home.

“Naomi needed to be observed for a much longer period, 34 minutes is just not adequate,” Gribbin said.

“She was six months’ pregnant ... her history was not sought, and yet she had been a patient at that hospital many times … Any pregnant woman who arrives in emergency with those kinds of symptoms, would be seen by a medical officer before being discharged.”

At the time, staff noted that Williams was “looking well in her face and her body overall”, “looked blossoming from pregnancy”, was “happy to go home and sleep”.

Naomi Williams died when she was six months’ pregnant, hours after being sent home from Tumut hospital. Photograph: courtesy of the Williams family

Her vital signs were taken twice, and showed a slight improvement. The inquest heard there was a period of eight minutes between the second observation of vital signs and when Williams was discharged from the hospital.

The experts said Williams’s Indigeneity, her previous history of complications and the stage of the pregnancy meant she was high risk.

“It has been established in the literature that Aboriginal women are at a higher risk of sepsis,” Douglas said.

“Any woman that appears that is six months’ pregnant has the potential to be high risk,” Gribbin said. “She should have been kept for a longer period of time, more observations taken and a doctor notified to assess her … I would expect someone to be kept a minimum of four hours.”

Both nurses criticised the failure to conduct a pain scale test with Williams. At the inquest in Gundagai, the midwife testified that she didn’t conduct a pain test because Williams “didn’t appear to be in a lot of pain.”

“It should have been done in any case,” Gribbin said. “[Pain] was one of her presenting symptoms. It is what brought her to emergency.”

“This was a young woman who fell unwell enough to take herself alone to an emergency department on New Year’s Eve,” said Douglas. “That itself was a red flag for me. [And] in the context of her being pregnant, I would have turned my mind to a pregnancy-related complication. Infection would have crossed my mind.”

The inquest also heard from two doctors, Randall Greenberg and Hilary Tyler, who specialise in emergency medicine in areas with large Indigenous populations.

The doctors said Williams should have been referred to a specialist months before she came to Tumut hospital on the night before her death.

Williams had three presentations to the hospital in 24 hours in June 2015, the inquest heard.

This was “completely” a red flag, Tyler said. “Specialist referral would have been a good thing to happen. And should have happened.”

“I would have thought a referral to a gastroenterologist would have been the best thing ... Wagga is about an hour and a half drive from Tumut,” Greenberg said.

Greenberg also countered the evidence of the nurses, saying it was “not unreasonable” to discharge Williams.

“Should it have been longer? I don’t think there is any right or wrong answer to that ... One of the previous witnesses said she had to be kept for four hours, well we’ve got this target that patients should be out of emergency within four hours.

“I think a lot of it depends on the conversation that happened, which we really don’t know. I don’t know if Naomi really wanted to go home, or if she wanted to stay there. Given that she looked well and she was in the white zone, it was not unreasonable to send her home, given she really wanted to go home.”

But Tyler said an average length of stay in her hospital, for those who are discharged, was two hours. “Maybe an hour is a good period of time at least, when there’s been a heart rate of 120,” she said.

Greenberg said it was “too hard to make a rule like that”.

The barrister for the Murrumbidgee Local Health District, Michael Fordham, questioned the two nursing experts’ knowledge, neither of whom had any midwifery training, though they did have knowledge of emergency procedures.

Fordham also told the inquest that Williams’s vital signs were in what is known as the “white zone” of a stable condition, rather than the “yellow zone”, which would indicate further monitoring.

Douglas replied that the first observation was “on the borderline of the yellow and white zone.”

“They were in the white zone weren’t they?” Fordham replied.

When asked the same question, Gribbin replied: “I don’t agree they were completely in the white zone. They were borderline. And the zones are merely a guide. Clinical judgment overrides any of those.”

He also asked whether the experts saw an improvement in the second set of vital signs.

“I would say it was a slight improvement,” Gribbin said. “Not enough to let me discharge someone.”

The inquest continues in Sydney.