Nitrous Oxide & Pregnancy: Risks and Safety Concerns

Question
Hello Doctor,
My daughter is pregnant and due July 4th, 2004.  She is a dental hygienist and is working as a substitute is a new dental office one day a week.  The office she works at now makes her leave the area if nitrous oxide (laughing gas) is used.  The new office uses this laughing gas on about 90% of the patients that come in for just about anything.  Do you know if there are any concerns about this gas for pregnant women?  She is only there one day a week for the next month, but we do not want to take any chances.  We just thought it strange that one dentist would be concerned, and the other not.  
Thanks in advance for your timely reply.
Jan

Answer
There is no harm in pregnancy (to the baby or to the mother) with the use of nitrous oxide for dental procedures. I would be more cautious about your daughter's exposure to X-rays performed in the dentist's office. Make sure that she is shielded by a lead wall or apron when she is involved in taking X-rays of patients.