In in Spain, the medication needed for your IVF treatment is covered by the social security only when the whole treatment is also covered in the same way. If you attend a private assisted reproduction clinic you will have to pay for the medication.
In the US, health insurance rarely covers the costs of the medication and you will have to pay for them.
In the UK, the NHS may cover part of the cost of the medication, but only if the treatment is being paid for by the NHS. If you are receiving private treatment then you will have to pay them separately.