The European Health Insurance Card (EHIC) gives access to any state-provided medical treatment that becomes necessary during your stay because of either illness or an accident. It includes treatment of a chronic or pre-existing medical condition that becomes necessary during your visit.
If you require kidney dialysis or oxygen therapy you have to make arrangements in advance for this care. To arrange for kidney dialysis while you are away, contact the renal unit in the country you wish to travel before you trip.
Your EHICard should cover you for routine maternity care while you are away. However, if you are going to another country specifically to have your baby, you will need an E112 form (or Document S2).
It is important to be aware, that the EHIC gives access to reduced-cost or free medical treatment from state healthcare providers and allows you to be treated on the same basis as a resident of the country you are visiting i.e. you may have to pay a patient contribution (co-payment).
Remember to check that your EHIC is still valid before you travel!