I had a right sided pleural effusion on 29th July 2011,nearly 650ml of water was removed surgically... since then i was put on anti tuberculosis drug therapy --- "ethambutamol,pyrizinamide,rifampicin and isoniazid."

After 3 and half months the doctor stopped pyrizanamide then after 15 days ethambutamol was also stopped..within four and half months the doctor confirmed that my lungs are clear... and now after completing the course for six months the doctor has taken the x ray... and it has come out to be normal... and doctor says that i am cured...
but he wants us to extend 3 months further with rifampicin-450mg and isoniazid-300mg... ( Rifiza) as he does not want to take any chance that pleural Tb may repeat ...

Question:---

Would it be safe to plan for a baby... and if we leave precaution then would it be safe for my baby if i get pregnant and had to take this medicine during first trimester of my pregnancy???
What adverse effects would it have on my baby.. or the foetus ???