Item — HN Reader

I hope "Don't smoke when pregnant" goes without saying. The mother's blood IS the baby's blood during pregnancy, anything the mother takes the baby gets. That's why 90% of medications are unsafe to take when pregnant.

I would hope this would be common knowledge.

2 comments

> The mother's blood IS the baby's blood during pregnancy, anything the mother takes the baby gets.

This is not really true[0]:

> In the villi, these vessels eventually branch to form an extensive arterio-capillary-venous system, bringing the fetal blood extremely close to the maternal blood; but no intermingling of fetal and maternal blood occurs ("placental barrier").

There is some pass-through effect, but it is not 100%, and varies depending on the particular chemical.

[0]: https://en.wikipedia.org/wiki/Placenta#Fetoplacental_circula...

There's more to it than that - 90% of medications are untested for their effects during pregnancy because doing studies on pregnant women is seen as unethical/too-risky. This is a huge problem since pregnant women have no idea what is safe to take. Some of it is _probaby_ safe, but we have no idea.