Doctors have described a constellation of birth defects, including conjoined toes and bent feet, as consequences of expectant mothers using fentanyl while pregnant.

The Delaware-based pediatricians have identified 10 babies with the defects in their state, as well as in California, Boston, and Rhode Island believed to be suffering from fetal fentanyl syndrome.

Their report is the first to uncover a link between the deadly street drug fentanyl currently tearing its way across the country and these birth defects, possibly because patients often withhold their history of drug use.

In addition to causing conjoined digits and bent ‘rocker bottom feet’ – named for the way bent feet resemble the legs of a rocking chair – fetal fentanyl syndrome can lead to cleft palate, an unusually small head, and neurological and behavioral issues lasting into adolescence.

Fentanyl has affected millions of lives, and pregnant women are no exception. Deaths caused by the drug, which is 50 times stronger than heroin, more than tripled from 2016 to 2021, rising from 5.7 per 100,000 persons in 2016 to 21.6 in 2021.

Further evidence is needed to prove without a doubt that fentanyl is the cause of these birth defects, which is not yet settled scientific fact.

The National Institutes of Health, for instance, said just two years ago that, ‘Based on the studies reviewed, exposure to fentanyl is not expected to increase the chance for birth defects above the background risk.’

But researchers from Nemours Children’s Hospital in Delaware who authored the latest study believed that their ‘striking’ discovery of a common thread between all 10 babies was compelling.

They said: ‘No common genetic or genomic abnormality was identified, but prenatal fentanyl exposure was shared among the pregnancies.

‘Although fentanyl’s effect on cholesterol metabolism has not been directly tested, based on indirect evidence it is biologically plausible that it affects cholesterol metabolism in the developing fetus.’

They posited that when a mother uses fentanyl during pregnancy, the drug disrupts the processes by which the body produces, uses, and eliminates cholesterol, a fat molecule that is essential for building membranes around cells as well as producing hormones and vitamin D.