**1. Classification and epidemiology of hypertension during pregnancy**

Hypertension is the second most prevalent maternal complication worldwide after anemia in pregnancy, and it is associated with a significant morbidity and mortality of the mother and fetus. The American College of Obstetricians and Gynecologists Task Force on Hypertension in Pregnancy has modified the older classification of hypertension during pregnancy in only four categories: (1) preeclampsia-eclampsia, (2) chronic hypertension (of any cause), (3) chronic hypertension with superimposed preeclampsia, and (4) gestational hypertension (**Figure 1**). It has been suggested that an older category, "unclassified," be reintroduced or replaced by "suspected" or "presumptive" preeclampsia [1].

In 2017, the American College of Cardiology and American Heart Association (ACC/AHA) issued a clinical practice guideline on hypertension that reclassified the previous category of prehypertension into elevated BP (systolic BP 120–129 mmHg) and stage 1 hypertension (systolic BP 130–139 mmHg or diastolic BP 80–89 mmHg) [2]. However a rise of diastolic blood pressure over prepregnant levels (delta hypertension) rather than a rise above absolute value is also a significant predictive marker.

**Figure 1.**

*Classification of hypertensive disorders in pregnancy.*
