Heart strain medication

My OB referred me to a cardiologist due to shortness of breath, which I just attributed to baby's position. I had to have a 24-hour heart monitor. The results showed heart strain and leg vein problems (not given any more details than this). The cardiologist even said no more pregnancies for me, which isn't a problem, since we already decided no more after this one. The cardiologist prescribed lisinopril and metoprolol succinate. The lisinopril shows side-effects of serious, even fatal harm to unborn babies. The cardiologist knew I am 36 weeks, and I even asked the pharmacist if these were safe in third trimester pregnancy. He said they were. Anyone know about this or have opinions? I don't plan on taking them until I talk to my OB.