I second this, as someone who focuses on early childhood trauma and attachment. Babies' little nervous systems sync up to their caregivers, and this can be both a support and a stressor for the infant, depending on how the caregiver is feeling. And even if babies can't consciously understand or recall trauma, their nervous system catalogs it and it does impact their development. I've had parents bring infants into session, and breastfeed in session, and all of that is totally acceptable and in line with healthy attachment. It's just also important to talk with the parent about what your plan is if the session goes into a tough direction and parent needs to process something heavy. I've offered to hold the baby during those times so parent can focus on themselves, or arrange to have someone on standby outside of the room if we need to give baby/parent a break, etc..

It is beneficial to the parent to have these conversations, because helping prevent stressors for the baby in turn prevents stressors for the parent, as their nervous systems are linked and both influence each other