Suggest Treatment To Increase The Breastmilk

Hi, My wife is not able to breastfeed the bay properly and we are using lactogen for now. My baby is 1 week old. She has got a flat nipple and hence there is latching problem. We also not sure if she has got enough milk to feed the baby. While pressing the breast, milk comes as drops. But its not coming while using nipple sheild. Could you please advice how to correct the problem?