A hormonal pregnancy test believed to cause birth defects was used in New Zealand, Medsafe has confirmed.
Medsafe has this afternoon confirmed Primodos first appeared in New Ethicals in 1966 - suggesting it was available and prescribed in New Zealand from that time. It was pulled from the market in June 1975.
Over the weekend, evidence emerged in the United Kingdom which showed women who took the hormone-based pill Primodos - also marketed as Duogynon in Germany and Ireland - in the 1960s and 1970s had a higher chance of having children with severe deformities or other serious health problems.
Medsafe manager Chris James said minutes from the Drug Assessment Advisory Committee in 1975 recommended that Primodos should be withdrawn from the market in New Zealand due to reports received from overseas that birth defects had occurred when hormonal pregnancy tests were taken in early pregnancy.
The NZ Department of Health withdrew Primodos from the market and removed stock from pharmacies in June 1975, he said.
Mr James said there was no information on how many patients were prescribed the product but Medsafe had contacted Bayer, the manufacturer, to obtain any information available.
The Centre for Adverse Reactions Monitoring in Dunedin confirmed it did not receive any reports of foetal malformations associated with the use of Primodos but did get one report that described an adverse reaction in an adult.
Medsafe had a memorandum of understanding with its British equivalent, the Medicines and Healthcare products Regulatory Agency (MHRA), he said, and would receive any relevant information as soon as it became available.
Prime Minister Bill English said the reports from the UK were sufficiently concerning to warrant the investigation by Medsafe.
He could not say what action would be taken if it was confirmed Primodos was used in New Zealand.
"I simply couldn't say, it is at very early stages of investigating whether it was used or not, let alone whether it had any impact or if there were any consequences from that."
Labour's health spokesman David Clark said officials needed to establish a registry and provide information for people who thought they may have been affected.
"That should happen post haste," he said. "The evidence in the UK points towards thousands of families being affected.
"I understand the drug was prescribed in New Zealand and there may be dozens or hundreds of women and families affected here."
A Primodos oral packet is held in Te Papa's collection, a sample packet donated by Dame Margaret Sparrow when she donated her collection of teaching materials in 2010 and 2011.
Dame Margaret, one of the first doctors to prescribe the emergency contraceptive pill, said as far as she knew Primodos was sold for a time in New Zealand.
"As far as I know it was sold for a time then I understand it was withdrawn. But I don't know how frequently it was used."
Primodos was first introduced in 1958 in Britain and was on the market for 20 years.
The drug contained high levels of synthetic progesterone, a hormone that helps maintain pregnancy. Women were told they were pregnant if they did not bleed after taking the tablets. But some of them suffered miscarriages and others had babies with birth defects.
The drugs contained 40 times the dose of a contraceptive pill and 30 times that of a morning-after pill.
British media reported that hundreds of families have long claimed that Primodos caused birth defects and they have been battling for years for compensation.
Until now, campaigners were unable to establish a causal link between the drug and their babies' health problems.
But they have been given hope by the discovery of archived documents in Germany which drew a connection between the two.
That has prompted the campaigners to allege a cover-up and compare it to the Thalidomide scandal, in which thousands of mothers gave birth to children without limbs or with other defects after being prescribed the morning sickness drug.
According to the documents, a principal medical officer for the British Government discovered in 1975 that women who took a hormone pregnancy test had a "five-to-one risk of giving birth to a child with malformations".
The medical officer alerted the drug's German manufacturer, Schering - which was bought by Bayer in 2006 - so it could address the problem.
The drug was not removed from the market for another three years.
The archived files showed that the officer destroyed materials which he used to make his findings "to prevent individual claims being based on his material".
Schering continues to deny any wrongdoing.
The Telegraph reported that Bayer had rejected any suggestion Schering had concealed any information. It also rejects any links between the drug and birth defects.
Women's Health Action strategic adviser George Parker said the organisation was strongly supportive of the reviews taking place in New Zealand and overseas.
Parker said she encouraged women who had taken the drug to get in touch with Women's Health Action or Medsafe to register any concerns.
She advised women to retain a level of cautious scepticism around drugs or devices prescribed during pregnancy and seek help to make an informed decision.