Chronic hypertension is defined as
SBP ≥140 mmHg or DBP ≥90 mmHg
that is observable before pregnancy
or before the 20th week of gestation.
It can be found at the gestational age of >20 weeks
or persist in 12 weeks post-partum.
The incidence of chronic hypertension is estimated 1-5%
of pregnancies depending on age and ethnicity/race.
Recent reports reported that the incidence occurs on Afro-American race and it is 1% for other races.