There are actually 2 questions being asked here which are:

• Can I pass poison ivy to another person?
• Can a newborn get a poison ivy rash?

In answer to the first, provided the person with the rash has done all the proper cleanup measures then the rash cannot be passed on. Clean up includes washing with soap and water thoroughly including under fingernails, and cleaning all items in contact with urushiol oil including clothes, shoes, etc. The rash is actually an allergic reaction to the urushiol oil bonding with the skin. Once bonded, the urushiol oil is not "going anywhere". And washing removes any oil that has not bonded.

In answer to your second question, this is the more interesting (to me). The urushiol oil induced rash is an immune system reaction to a foreign entity. Newborns don't have an adequate immune system to attack so no rash. There are a number of studies which note that there is an age difference in susceptibility. Here is one of my favorite papers: Secondary Compounds Within the Anacardiaceae. Suffice to say this is technical but is a research paper which draws on a large body of research papers for support. So a benefit of getting older is that eventually, our reaction to the urushiol oil will decrease. Another factor in reaction is that most people never get a rash on first contact with urushiol oil, it can take many contacts before the first onset of rash.

Now for the short answer: No - not going to be passed on to the newborn. But it would be prudent to make sure that there is no urushiol oil remaining (tools, clothes, fingernails, etc.) that can be passed from one person to another.