Yes, Nicardia (Nifedipine) is widely and safely used during pregnancy. Although it is primarily a blood pressure medication, your doctor has prescribed it to relax your uterine muscles and prevent premature contractions, which is highly beneficial since you have a cervical stitch. Since your blood pressure is currently normal, Nicardia may cause it to drop slightly. It is important to monitor yourself for dizziness, headache, or lightheadedness. Continue taking it exactly as directed, and consult your obstetrician if you experience any unusual symptoms.