Eh yes lah, nadi laju during pregnancy is quite common, a few of us mummies experienced it, especially in the second and third trimester because our blood volume increases and the heart works harder. Best to mention it to your doctor or midwife though, just to make sure everything is okay, especially if it comes with dizziness or shortness of breath! In the meantime, try staying hydrated, rest when you can, and avoid too much caffeine, some of my mum friends found that really helped calm things down.