Depends hugely on how the brand sizes things. H&M maternity wear runs quite small and you often have to size up from 2nd trimester. ASOS maternity wear is heyooge. A lot of brands essentially "vanity size" their maternity wear because women don't like going up sizes.
I’m normally an 8 up top and 10 on bottom. I’ve had to go up sizes to a 12-14 in normal clothes, ie baggy jumpers etc and maternity I went for 10 in both tops, dresses and trousers. I should have gone for 8 in dresses and tops and 10 in trousers. I still have plenty of room for bump to grow so I would say normal sizes.
I'm normally a 12, bought some second hand maternity trousers for work in a 12... For just ok now, bit tight on legs and theres no way they're going to last another 25 weeks...😳I think tops stretch better bit think I'm going to buy trousers as and when I grow out of them...
I'm normally a 10 but was on steroids at the start of this pregnancy and put on 8kg in the first 8 weeks! I've been wearing size 16 maternity jeans from H&M, but at the same time still fit into my size 10 work dresses and I'm 28 weeks - no idea how that works?! I think you just need to try different shops and see what works.
You can get away with normal tops and maternity trousers for quite a while in my experience. Just try them on if they feel tight now then go up a size. Dresses will be ok it’s more the waistbands- by the end you’ll want comfy rather than too structured. Get on eBay!