Usually they appear as the skin stretches in the second or third trimester. But if you have extreme itching along with it, please check with your gynac to rule out other issues.
Honestly, I was so worried about the baby's safety after my past loss that I didn't even notice when the stretch marks appeared around the 6th month. Just focus on your health, these marks are a beautiful sign of your strength.
Mine started in the late 2nd trimester as the baby grew. I was so focused on keeping my sugar levels in check with proper meals that I just used simple coconut oil for the skin stretching.
Ah, the Tiger stripes! They made an entry around the 24th week for me and decided to throw a party on my tummy. Don't sweat it, they just mean your little human is growing nicely.
For me, they started showing up around the end of the second trimester when my belly really started growing. Keep applying a good moisturizer, it helps with the itching too!
My marks showed up in the 7th month, mostly on my lower belly. After my C-section, I realized those marks and my scar are just reminders of how amazing our bodies are, so don't worry about them.