If immunity is in doubt, a blood test can check this and vaccines are available. You should be immune to these before your pregnancy. There are some other infections that can cause a problem in your pregnancy. These include Toxoplasmosis and Cytomegalovirus. You can reduce your risk by eating only well done meat, having someone else change the cat litter, wearing gloves when working in soil, and wearing gloves when changing diapers if caring for the children of others.
Safety is judged by considering how a medicine works and prior experience.
We balance the benefits with the risks. Tylenol, for example, is safe when taken as directed. Some medicines may be necessary for a healthy pregnancy. Please discuss all medicines with your doctor before your pregnancy. If you, your partner, or any blood relatives have any medical problems, history of birth defects, or frequent miscarriages than this should be evaluated before your pregnancy.