Why my wife get the hipertensi before the birth now ? but before the blood pressure is normal ?

Common: Many people develop hypertension during pregnancy. For most it is a reflection of their changed circumstances (increased weight and increases in circulating plasma volume --which increase up to 30-40% during pregnancy). For some it is a warning that they will be susceptible to HTN later in life. For some HTN during pregnancy might be dangerous (particularly if w protein in urine)-preeclampsia.