You may say "Yes, and then add a statement explaining that it was temporary Medicaid for pregnancy for you. You need to provide the evidence of this assistance. The WIC program and Medicaid was for your child, so you don't need to report it in your I-485 (your child is a US citizen, so this assistance is irrelevant to you).
You just need to descried what you got and for what use, and not need to explain more details. USCIS will decide whether the assistance you got belongs to public charge or not. Of course, the assistance you got is not public charge, so it will not affect your I-485 approval.