Pregnancy & Health Issues

I have neurocardiogenic syncope & postural orthostatic tachycardia syndrom. Does anyone have experience with either of these health issues & pregnancy? Long story short, my body doesn't push blood to the upper portion of my body upon standing so my heart rate increase 30+ bpm within seconds because it's trying to overcompensate. My heart eventually quits trying to pump and just restarts causing a sudden drop in heart rate causing me to passout. I've only ever passed out during a test. However, I'm curious if being pregnant can make symptoms better or worse. Anyone have either of these diseases?