Ayy, palpitations masa pregnant memang common la, especially at 17 weeks when your blood volume is increasing quite a bit, a few of us mummies experienced it jugak! Tapi since this is your heart we're talking about, better to mention it to your doctor at your next appointment or call them up if it feels really intense or you're worried, sebab they need to check properly and rule out anything. Hopefully it's just normal pregnancy stuff, but peace of mind dari doctor is the best thing you can do right now!