Abiding by the old rules and waiting for a severely preeclamptic patient's diastolic blood pressure (BP) to reach or rise above 110 mm Hg before beginning to treat hypertension can invite a deadly stroke, warned a leading Jackson, Miss. maternal-fetal medicine researcher. Instead, consider treating as a hypertensive emergency a pregnant patient's sudden severe systolic BP reading of 155 to 160 mm Hg or more, regardless of the diastolic reading, said James N. Martin, Jr., MD, Professor of Obstetrics and Gynecology, and Director of Maternal-Fetal Medicine and Obstetrics at the University of Mississippi School of Medicine.