People who share a child and who aren't in a relationship any longer will have a child support order in place. While this is usually associated with regularly occurring payments from one parent to the other for the child, there is another point that is usually covered in these orders – medical care costs.
Typically, one parent is required to carry the child on their medical insurance. While this covers many of the child's medical expense, there are other health care costs that have to be covered. These uninsured expenses include things like co-payments and deductibles, as well as anything else the insurance won't pay that the parents have to cover out of their own pockets.
There are many ways that the uninsured costs can be covered, so you must consult the order to determine what is required in your case. If you don't have an order yet, you will likely end up with one of these methods.
One is that the parents split the costs equally or on a percentage basis with each parent assigned a specific percent. Another is that one parent is responsible for a set dollar amount per month, quarter or year. The other parent is responsible for anything beyond that cost.
There also has to be an agreement about when these costs will be settled. Typically, the parent who is with the child will cover the out-of-pocket expenses that occur. The other parent will then have to reimburse that parent for their share.
Parents who are in this situation need to ensure that there is a clear definition of what is considered a reasonable medical expense. In most cases, only ones that fall under that umbrella are covered by the medical care cost terms of the support agreement.