Insulin and labour and delivery

Just Me ā€¢ Have a 4 year old daughter and a Newborn GLOW baby girl born 22/04/15..so in love šŸ’•
So ive started insulin injections and have to still take my 3x metformin a day as well for GD. 
How does insulin have an effect on labour and Delivery? Any extra things that will happen/need to be put into place now?