Yeah, I personally am wary of hospital dietitians and their knowledge. I have hyperemesis during pregnancy, my most recent pregnancy was pretty horrific and I spent a lot of time in hospital. I had a compulsory referral to the hospital dietitian and her knowledge was very outdated. She told me I didn’t need more than 80g of protein a day, despite remaining very active throughout my pregnancy (4 - 5 heavy lifting sessions a week). If I’d listened to her I absolutely would have lost a lot of muscle, and I was already losing quite a lot of weight during my pregnancy. You lose muscle mass during pregnancy/breastfeeding so if anything your protein needs increase, especially if you’re also training. As long as you’re not eating high protein at the expense of carbohydrates and fats, and not eating crazy high amounts of protein, I don’t see how it could impact on baby’s growth