Six Kiwi babies have died from syphilis passed on in pregnancy - and a testing loophole is putting families at risk.
New Zealand is in the midst of a worsening syphilis epidemic, with reported cases surging by more than 500 per cent in five years.
The sexually transmitted infection can pass from mother to unborn child in pregnancy and, if untreated, cause miscarriage, stillbirth, deafness and deformities.
Screening pregnant women for the disease is crucial - but a Herald investigation has found a weakness in the current testing regime meant infections weren't detected, despite parents doing everything right.
Experts are now calling for all women to be tested twice - once early in pregnancy, as happens now, and again in the third trimester.
Most women who have lost babies are Māori - children dying again, some 250 years after congenital (mother-to-child) syphilis arrived in New Zealand following visits by James Cook's ship, the Endeavour.
Dr Jane Morgan, clinical director of Waikato DHB's Hamilton Sexual Health, said the deaths were preventable.
"This should not be happening in our country. In medicine we call it a sentinel event. It's meant to be a disruptor, it's meant to make you sit up and go, 'What's going on?'
"It's something massive happening. And we all need to work out what we're going to do to fix it."
Syphilis is a sexually-transmitted bacterial infection that spread among medieval armies and was blamed for monarchs' madness. The disease afflicted as many as one in 10 Londoners by the start of the 20th century, but was largely eradicated in developed countries after the discovery of penicillin.
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However, syphilis is back; its resurgence in the Western world turbo-charged by dating apps, international travel, poverty, and health services unprepared for an epidemic most thought consigned to medical history.
In New Zealand, most reported cases are among men who have sex with men, but an increasing number affect women of child-bearing age.
In 2016 that produced the "trainwreck" sexual health clinicians have long warned of - a stillbirth caused by syphilis passed on from the mother.
It proved no outlier; in the following two years there were nine mother-to-child infections, five of which caused stillbirths (some remain under investigation).
The youngest woman to lose a child was a 16-year-old, who suffered a stillbirth at 27 weeks gestation.
There are already another three suspected "live birth" cases this year.
The toll is probably greater, because deaths are only recorded if they happen after 20 weeks gestation. Earlier miscarriages are likely to have been caused by syphilis, but don't show in official statistics.
Experts say there's an urgent need to upskill GPs and health workers, and properly fund sexual health services. There are only about nine full-time sexual health specialist positions across New Zealand's 20 DHBs.
All women should get a blood test for syphilis and HIV when they start antenatal care.
Morgan and other sexual health clinicians want that repeated in the third trimester, to catch cases where infection happens during pregnancy. Syphilis can take up to three months to show in testing, so re-testing also acts as a backstop for infection too early to show up in the first blood test.
Under existing guidelines, "at risk" women - who have an STI or sex with a new partner in pregnancy - should be re-tested. However, asking such questions can be awkward, particularly if pressed for time. There's also the possibility the father has other sexual partners.
The Herald understands cases of congenital syphilis weren't detected, despite the mothers being tested early in pregnancy. In one case, a woman fell pregnant soon after meeting her partner. An infection didn't show up in the blood test done early in the pregnancy.
Closing the testing loophole would cost about $270,000 a year (a test costs $4.50, about 60,000 women give birth annually).
The Ministry of Health says a professional body, the NZ Sexual Health Society, will finalise national guidelines for treating maternal syphilis by the end of the year, which are likely to include a recommendation on third trimester screening.
A national syphilis action plan is also being developed to respond to the epidemic, along with regional responses.
Dr Niki Stefanogiannis, the ministry's deputy director of public health, said mother-to-child syphilis "reflects international trends, and reinforces a global need for action".
"Most cases of congenital syphilis in 2017 and 2018 presented to health services very late - either in labour or in the week before labour.
"We're looking at the best ways to provide advice to lead maternity carers and to develop educational resources for pregnant women and their LMCs."