Throughout your pregnancy your doctor monitors your blood pressure, weight, and the amount of protein in your urine. Among other conditions, your doctor is screening for hypertensive disorders during these regular prenatal visits.
Blood pressure measurements include both systolic blood pressure (when the heart contracts and pushes blood out of the heart and through the arteries) and diastolic blood pressure (when the heart relaxes and fills with blood from the veins). A systolic blood pressure above 140 mmHg or a diastolic blood pressure above 90 mmHg is abnormally high for a pregnant woman. Pregnant women with blood pressure above these levels twice at least six hours apart are diagnosed with hypertension.
Weight gain of more than two pounds in any given week or six pounds in a month may be a sign of developing preeclampsia. In rapidly worsening cases of preeclampsia, weight gain may exceed ten pounds per week. This weight gain is due almost entirely to abnormal fluid retention that causes excessive swelling ( edema ) of the face, hands, and extremities.
Proteinuria, or protein in the urine, is indicative of preeclampsia. If proteinuria is found through a dipstick test of your urine during a routine visit, your doctor may test a 24-hour urine sample. This helps differentiate proteinuria from other conditions. You doctor may also perform blood tests to check for damage to your liver, kidneys, or blood cells.
If you have high blood pressure but no excessive weight gain, abnormal swelling, or proteinuria, you will be diagnosed with hypertension. Your doctor monitors you closely throughout your pregnancy for signs of developing preeclampsia or eclampsia. If hypertension is diagnosed after the 20th week of pregnancy, is relatively mild, does not compromise the pregnancy, and returns to normal after delivery, you are retrospectively diagnosed with gestational hypertension.
If your doctor finds proteinuria, sudden weight gain, or swelling during the physical examination, you are tested for preeclampsia.