The phrase "to affect the baby" means that something has an impact or influence on a young child or an unborn child. It refers to how actions, events, or substances can cause changes in the baby's development or well-being. Full definition
A scarf would do the trick and wouldn't affect the baby in the least. (thestir.cafemom.com)
The choices made during pregnancy also affect baby's health and can even help influence how baby's genes are expressed. (akashacenter.com)
It may not directly affect your baby in a bad way, but high sugar will cause your baby to grow rapidly and make normal delivery difficult. (kaboutjie.com)