[fnordfnordfnord]

> It's a hypothesis that might be worth investigating,

I don't disagree with that and I wouldn't be surprised to learn that such a study already exists.

>I would be surprised if there was no effect observed.

There are a lot of things that can cause premature labor. My personal opinion is that it is just as likely to be some stress otherwise related to their environment, or even stress related to the process of obtaining illegal drugs.

[foobarbazqux]

My guess is that if we controlled for environmental and purchasing stress, more crack use alone would lead to more stress, possibly in a dramatic way depending on the levels.