I suggest you wait to be seen before beginning attempts to conceive, but if not, you are doing all the right things for now.
Regarding your questions. You will likely be switched from toprol and put on Labetalol in pregnancy. Both are beta blockers, but Labetalol has a better safety track record in pregnancy and thus more commonly used.
From what you have told me you will be at an increased risk for pre-eclampsia because of your weight, family history (it probably runs in families due to the same reasons a persons hypertension runs in a family), and history of hypertension. If you are over 35 that too is a risk factor.
There is not much you can do to prevent it. Regular and early prenatal care is the best thing you can do.
And lastly, placent previa is not a heritable condition.
Thank you for your questions.
Good luck and best regards,
Hello I'm 42yr's old and trying to have anyother baby, but i feel that my blood pressure is stoping me and of course my age. I'm on Methyldopa 250mg and 4 times a day and my pressure is still running 170/103 . I'm scared but it does run in the family, my Dr. just said to keep taking the med's 4times a day . Will i ever get pregant again with this HIGH BLOOD PRESSURE.