How can I tell which medications are safe to use during pregnancy?" A: Open any prescription or over-the-counter drug insert and read the fine print (if you can)
X-rays During Pregnancy Is it safe to have x-rays while I'm pregnant? What are x-rays? Do all types of x-rays have the same amount of radiation? I found out I'm pregnant after I had an x-ray.
... is not to say that inhalation or topical application of every oil is safe. Here is a list of non-mainstream oils (due to their overall toxicity) which should especially be avoided during pregnancy.