Artist

First, this is something that you should really be discussing with your doctor. You should make them aware of any hazardous materials (and situations) that are part of your work and they will give you the appropriate advice. 
There is too much to cover in any online post particularly with no details on your specific situation, but, in general, fetuses are often more susceptible to certain toxins than adults. Different chemicals have different ways that they are transmitted from mom to baby, so there is not one overarching answer to this other than mom should limit or eliminate exposure during pregnancy.
The American Institute for Conservation’s Health and Safety Network did an article on pregnancy in conservation. Many of the issues addressed here are also relevant to artists. The article was vetted by industrial hygienists and H&S experts specializing in conservation and collection care issues:
https://www.culturalheritage.org/docs/default-source/publications/periodicals/2012sept-aicnews.pdf?sfvrsn=cee29d83_8
Here is another article on this topic written by an industrial hygienist (someone who specializes in controlling workplace hazards):
http://www.techtoolstraining.org/spotlight/2018/12/5/painting-while-pregnant-teproductive-hazards-in-the-scenic-and-props-artists-workplace
Note that the advice, resources and situations described above do not take the place of talking with your doctor, who knows your personal health history. Be very cautious of online advice and make sure the individual providing information is qualified and knowledgeable. Having been a pregnant conservator myself, I know that the internet is a scary source of bad information.
Kerith Koss Schrager