Gestational diabetes

A 57yo male with a 20 year history of diabetes mellitus type previously treated with glyburide 5mg po twicw a day, metformin 1000mg po twice a day, and rosiglitazone 8mg po one a day. He is interested in transitioning to insulin therapy.

How should  Gestational diabetes be started on insulin therapy? How should the insulin be monitored and adjusted?

What other adjustments to medications may be necessary as the insulin regimen intensifies?