Hypertensive disorders in pregnancy are multifactorial in onset and can have a variety of maternal underlying pathologies as well as being influenced by environmental factors during pregnancy. The disease varies in urgency during pregnancy and can show progressive changes and can deteriorate rapidly.
I. Hypertension in pregnancy
Hypertension with systolic blood pressure ≥ 140 mmHg (1 mmHg = 0.133 kPa) and/or diastolic blood pressure ≥ 90 mmHg first appears after 20 weeks of gestation and returns to normal within 12 weeks after delivery; negative urine protein test. Systolic blood pressure ≥ 160 mmHg and/or diastolic blood pressure ≥ 110 mmHg was considered severe gestational hypertension.
Pre-eclampsia – eclampsia
1. Preeclampsia: systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg after 20 weeks of gestation with any of the following: urine protein ≥ 0.3 g/24 h, or urine protein/creatinine ratio ≥ 0.3, or random urine protein ≥ (+) (test method when urine protein quantification is not available); no proteinuria but with any of the following Involvement of one of the organs or systems: vital organs such as heart, lung, liver, kidney, or abnormal changes in the hematologic, digestive, or neurologic systems, placental-fetal involvement, etc. Persistently elevated blood pressure and/or urine protein levels, impaired maternal organ function, or placental-fetal complications are signs that preeclampsia is progressing to a severe form.
Pregnant women with preeclampsia are diagnosed with severe preeclampsia when any of the following manifestations are present.
(1) Persistently elevated blood pressure: systolic blood pressure ≥ 160 mmHg and/or diastolic blood pressure ≥ 110 mmHg.
(2) Persistent headache, visual disturbances, or other central nervous system abnormalities.
(3) persistent epigastric pain and manifestations of subperitoneal hematoma or liver rupture.
(4) Abnormal liver enzymes: elevated blood alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels.
(5) Impaired renal function: urine protein >2.0 g/24 h; oliguria (24-h urine volume <400 ml, or urine volume <17>106 μmol/L per hour).
(6) Hypoproteinemia with ascites, pleural fluid or pericardial effusion.
(7) Hematologic abnormalities: persistent decrease in platelet count below 100 x 109/L; microvascular hemolysis [manifested by anemia, jaundice, or elevated blood lactate dehydrogenase (LDH) levels].
(8) Cardiac failure.
(9) pulmonary edema.
(10) Fetal growth restriction or low amniotic fluid, intrauterine death, placental abruption, etc.
(2) Eclampsia (eclamgsia): convulsions that cannot be explained by other causes occurring on the basis of pre-eclampsia.
3. Pregnancy combined with chronic hypertension
Pre-existing hypertension or systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg found before 20 weeks of gestation, without significant exacerbation during pregnancy; or hypertension first diagnosed after 20 weeks of gestation and persisting beyond 12 weeks postpartum.
IV. Chronic hypertension complicated by preeclampsia
Pregnant women with chronic hypertension, no proteinuria before 20 weeks of gestation and urine protein ≥ 0.3 g/24 h or random urine protein ≥ (+) after 20 weeks of gestation; or proteinuria before 20 weeks of gestation and a significant increase in urine protein quantification after 20 weeks of gestation; or any of the above manifestations of severe preeclampsia such as further increase in blood pressure.