I have the exact opposite, I'm 7.5 weeks and my mother is really not interested, keeps down playing my intense morning sickness and texting my husband asking how 'the grumpy woman' is, only her word isn't woman - which is even more offensive as I genuinely have a strong hold over my emotions with her, which is to show none.
I had an ectopic scare in the beginning and her help was to tell me horror stories of death, infertility and depression. OH JOY! I'm a size 10 and already bloated and she said in front of about fifteen people "you're beefing up aren't you love". She is an absolute douche, but she's my douche.
If your mum wants to share parenting advice it's obviously because she's so proud of the job she's done on you. I understand how it could be annoying but you should try and see it as a reflection of her love, and she's still learning the rules of social boundaries in this example obviously.
It's great to vent about your mum, I get that, but when she's motivated by love and not just being an actual dickhead then maybe cut her a bit of slack. I'm not saying that you should be, just that I'm sure in this case there is definitely a silver lining.
Have a bitch about her and then ask her firmly but patiently to back the f**k off. If she doesn't, have some fun and wind her up about different styles of parenting you plan on using, feeding a mixture of goats and sheeps milk or some crazy names you're really passionate about.
Don't let it get to you and have some fun with it, my husband has already convinced mine that our child is getting the name of the pedigree cows we farm. I really hope it improves for you soon and wish you all the best with your pregnancy, but it is your pregnancy not hers.
Sam x