Headaches and pregnancy

I am 29 years old and pregnant with my first daughter.  Pregnancy thus far has gone excellent with no problems at all.  I do have a past history significant for an arrhythmia that had to be ablated on my sinus node, thus leaving me dependent on a atrial single chamber pacemaker.  Heart has caused me no problems so far and just recently had an echo done which looked normal.  I am 21 weeks along and doctors are pleased with my BP's, which have been normal and my weight gain thus far.  Just recently, at about 19-20 weeks I have been getting really bad headaches.  Sometimes they wake me in the middle of the night and they seem to come and go.  I've been drinking plenty of water, so I don't think it's dehydration.  Could it be my body just adjusting to blood volume changes, hormones?  I thought most of these adjustments took place in the first trimester, that is why I'm a little concerned.  Do you think it is a pre-cursor to pre-eclampsia?  I haven't noticed any swelling of my extremities or anything.  Also, can I expect to have a natural vaginal birth with my pacemaker?  I can't see how a pacemaker could hold me back from this.  I am very active and healthy.  Have you delivered babies to women with pacemakers and did the delivery go smooth?  Thanks for your help and advice!

[Keli927]

Hi I am 18 weeks and have bad headaches too. My BP is fine so the drs says its stress and hormones from pregnancy. They are awful though and they scare me. I really hope thats all it is.