DS also developed jaundice. It got close to their cutoff, but he was able to avoid going under lights. Because it was day 2/3 and my milk hadn't come through the paed strongly recommended that he had formula (40mls every 3 hours from memory) to flush out his system and to put him under the window for the UV. I was really apprehensive about giving him formula (after everything I'd read here) but agreed to. The jaundice cleared up enough for us to go home when we were meant to, so it worked out in the end. Also, despite him having the formula for a couple of days in hospital, I was able to establish a good supply and we went on to breast feed until he was 21 months (without any top ups after the first week). HTH