The death of Australian doctor William McBride, who helped expose thalidomide as a drug that caused birth defects, has hit the headlines today.
But what is thalidomide, and what exactly did Dr McBride do?
Thalidomide is a drug that was widely used by pregnant women in the late 1950s and early ’60s to relieve nausea and as a sedative, but it was later shown that women who took the drug in early pregnancy were at increased risk of having a child with physical abnormalities.
Over the few years it was in widespread use in Australia, Europe and Japan, about 10,000 children were born with phocomelia, or malformed limbs.
Dr McBride, who was practising as an obstetrician and gynaecologist in Sydney at the time, is credited with writing the first English language medical journal reference linking thalidomide with birth defects.
In a 1961 letter published in The Lancet, he wrote:
“Congenital abnormalities are present in approximately 1.5 per cent of babies. In recent months I have observed that the incidence of multiple severe abnormalities in babies delivered of women who were given the drug thalidomide (‘Distaval’) during pregnancy, as an anti-emetic or as a sedative, to be almost 20 per cent.
“These abnormalities are present in structures developed from mesenchyme—i.e. the bones and musculature of the gut. Bony development seems to be affected in a very striking manner, resulting in polydactyly [extra fingers or toes], syndactyly [fused fingers or toes], and failure of development of long bones (abnormally short femora and radii).
“Have any of your readers seen similar abnormalities in babies delivered of women who have taken this drug during pregnancy?”
W. G. McBride
This publication was a catalyst for further examination of the dangers posed by the drug and Dr McBride was lauded for his role in exposing the abnormalities.
Questions were eventually raised, however, about the extent to which he deserved that credit.
“This was the first published notification of concern, but the reality was that a nurse at Crown Street [Women’s Hospital] had noticed a few babies being born with limb defects,” said Norman Swan from ABC RN’s Health Report.
“They were mostly, if not all, Dr McBride’s patients — and the only thing she could put it down to was that Dr McBride had started prescribing thalidomide as an anti-nausea drug when the other obstetricians hadn’t.”
Dr Swan subsequently reported on fraudulent research by Dr McBride, in relation to a different anti-nausea drug, in the late 1980s.
Nonetheless, Dr McBride’s actions were critical in raising awareness about the effects of thalidomide.
One drug, many effects
The drug was taken off shelves in Australia in 1961 and most other countries around the same time.
Part of the reason it took so long for the link between the drug and the defects to become apparent was because of the separation between the psychiatrists prescribing the medication and the paediatricians treating the babies, as well as the time lag between exposure to the drug in the first trimester of pregnancy and the affected baby being born, according to medical historian Arthur Daemmrich.
Although the science is still not completely clear, it’s thought the drug causes birth defects by inhibiting the development of new blood vessels at a crucial stage in pregnancy.
It took researchers many years to form this theory, because thalidomide is broken down into more than 100 potentially defect-causing components in the liver, which needed to be studied.
Further complicating the matter was that fact that common lab animals like rats and mice are not affected by the drug as severely as humans.
The drug was not approved in the United States when it was first submitted to the Food and Drug Administration in 1960, thanks to pharmacologist Frances Oldham Kelsey, who was tasked with reviewing the application and was uncertain it was as safe as was being claimed.
While thalidomide was withdrawn from the Australian market in 1961, it has been used in Australia since 2001 as a treatment for rare diseases such as leprosy and bone marrow conditions.
The Therapeutic Goods Administration in 2003 registered the drug for the treatment of the blood cancer multiple myeloma, and a form of leprosy.
Analysis by Tegan Taylor, ABC