Most women would prefer to view pregnancy as a natural part of life and not a medical condition. When faced with underlying disorders that require treatment, or frequent complications as a result of such natural conditions, this can pose both a physical and an emotional challenge. Furthermore, clinical experience has shown that many but not all women give higher priority to the health of their unborn child than to themselves if they made to choose one over the other. For clinicians it is therefore important to consider benefits and risks of treatments carefully for both mother and child and use the best available evidence to guide patient care. Common problems faced in this setting are discussed in this chapter.