Planning ahead – having a baby

My husband and I are planning to (hopefully) have a baby in the nearish future. With that, we are planning ahead for healthcare costs primarily from a prenatal care and labor/delivery cost.

My insurance year runs July-June and I am currently on a plan by myself. When we have a kid the child will be added to my plan. I am currently on our lowest tier plan with a $2500 single deductible and $5500 out of pocket max. Deductible/OOPMax on that same plan as a family is $5000 and $11000. I am looking into jumping up to our next deductible/HSA plan or even our PPO. Next tier plan is $2000 single and $4000 family deductibles, $3000 single and $6000 family OOPMax. PPO is $800 single and $1600 family deductible, $3000 single and $6000 family OOPMax.

My primary question is related to how the deductible and OOPMax works when I will be on a single plan up until delivery and then I will be adding my child within the 30 day QLE window to bring us into a family plan. For example, if I hit my $2500 deductible before delivery but then I eventually am getting back-dated to a family plan and 5k deductible with the delivery how is the being billed. Will the delivery be my 20% coinsurance with a $2500 deductible or will it not hit the coinsurance until I hit 5k deductible because the baby gets added with the same DOS as the delivery.

Let me know if this doesn’t make sense. Writing it out sounds confusing probably because I am confused!