Giving Baby formula to EBF baby

Dominique

Hello! My baby girl is 4.5 months and weighs close to 12 lbs. doc said that “she could be gaining more weight” and to try supplementing formula. She’s EBF. We’ve tried 3 different brands, liquid and powder and she REFUSES. I don’t make an over abundance of milk and don’t get much while pumping. We’ve also tried several types of bottles. Any tips for me?

Also, should I be concerned about her weight? My son was the same way (26 months now and is just 30 lbs). She’s happy and healthy and meeting milestones!

Thanks in advanced ;)