can't drink milk during pregnancy

If you're referring to cows milk, there haven't been proper studies in co-relation to health benefits. Basically it was a marketing strategy back in the days to sell it as a necessity in everyday life. All you need is just one study that could prove some co-relationship no matter if it's significant or not at all. Milk has calcium and calcium is required for great bone etc. so just on this basis, the marketer did a great job despite having hormones and pus found milk. There are many sources of calcium like soya milk nutrisoy from veges etc. I'm a nutritionist and I have never had milk since I stopped in kindergarten 😅 despite having gone through a few surgeries where doctor prescribed me with those formulated high dense milk I still recovered well and fine... You can eat more high nutritionally densed food