Talk with your OB/GYN about TTC while on this medication. Metoprolol is a Category C drug while used in the first trimester...if it is used during the 2nd and 3rd trimester it is a Category D. Im not trying to scare you but there are more BP meds out there that you could use. Since you take metoprolol Im guessing you need a beta-blocker drug instead of a diuretic, calcium channel blockers, alpha blockers, direct vasodilators, angiotensin II receptor blockers, or Angiotensin-converting enzyme inhibitors.
Other drugs that are considered beta-blockers are:
They all looked like Category B or D drugs that turned into Category D in 2nd or 3rd trimester. (safefetus.com)
You need to discuss this with your Dr before you become pregnant, but Im sure BP meds during pregnancy outweighs the possibilities what stopping them will do to your body.
Heres some articles:
Hope this helps and gives you some info on the issue. But if your Drs think its fine to contiune with the meds then Im sure its ok. Or ask your pharmacist what he/she thinks.