From slower metabolism and changing periods to sleep, skin and fertility, here's what women commonly notice in their 30s and when it's time to see a doctorA friend recently asked, “why does my body suddenly feel different?” Here’s what doctors say women commonly notice in their thirties, and why these changes matter more than we often think. Your periods might tell you more than you realiseFor most women in their thirties, periods remain regular. Also Read: Why age 35 isn't the fertility cutoff many believe it isThis does not mean pregnancy becomes impossible after 30. But it is also giving you valuable information: Health isn't about looking exactly as you did at 25.