Chronic Hypertension: 2 BP readings of SBP >=130 and/or DBP >=80 diagnosed before pregnancy or during pregnancy before 20 weeks gestation.

Gestational Hypertension: 2 BP readings of SBP >=140 and/or DBP >=90 diagnosed >=20 weeks gestation.
Other criteria include no hypertension <20 weeks and no preeclampsia features.

Preeclampsia: 2 BP readings of SBP >= 140 and/or DBP >=90 plus proteinuria and/or end-organ dysfunction diagnosed >= 20 weeks gestation.

Preeclampsia can be superimposed on chronic hypertension.
Criteria for <20 weeks gestation: chronic hypertension + preeclampsia features.
Criteria for >=20 weeks gestation: new proteinuria and/or end-organ dysfunction; OR worsening/resistant hypertension with preexisting proteinuria.

MNEMONIC: "Hypertension Is Practically Pregnancy's Only Abrupt Disorder"
IUGR
Preeclampsia
Preterm Labor
Oligohydramnios
Abruption Diabetes (gestational*)

*Gestational Diabetes is a risk factor for hypertension in pregnancy. All other outcomes listed are considered more likely in patient's with hypertension/preeclampsia.