Bueno amigos...hablo en inglés para me explico.
I'm not sure how it is being used in the context of health insurance and I have no idea of the Spanish word in this context so I'll just provide my insight on how it the word is used in English and hope it will help you find the right Spanish word.
Slots is a term used like
positions or placements,
usually indicating that there is a limitation on the number of "slots". Like, "There are still slots available for membership"; or "He was in slot #2 on the racetrack"; or "There is a slot open in the class you want"; or as Leslie and Merce said "
dates or appointments", like "The doctor has a slot open to see you on Tuesday"
It is also used to say something like "We don't have enough slots for everybody" in saying there is not enough room to accomodate everybody.
It seems clear that "The Children Trust does not pay for health insurance slots" means like Sandra and Exx suggest...that it does not pay for medical expenses. But what is the right word in Spanish? The usage is a little unusual.