Complex sentence: The administration of intravenous immunoglobulins requires the insertion of a cannula or needle in a vein, usually in the arms or hands; as they use highly concentrated product, IVIg infusions must take place every 3 to 4 weeks.
Split into simpler sentences: The administration of intravenous immunoglobulins requires the insertion of a cannula or needle in a vein, usually in the arms or hands. Because highly concentrated product is used, IVIg infusions take place every 3 to 4 weeks.