I know, it sounds very Victorian and old-ladyish, but the last couple of weeks I've had this horrible sensation where I feel like my breath gets caught in my throat and then I feel my heart kind of shuddering or shaking in my chest. It only lasts a few seconds but can happen several times over the course of a couple of minutes, then will stop for a day or so.
I've always been anxious during pregnancy (this is no.4 at 18 weeks) probably because one of my boys was stillborn at 36 weeks, but I'm not aware of being particularly stressed when this happens. Anyone else had this?! It kept me awake last night!