# Obstetrics and Gynecology/Hypertensive Disorders including Pre-Eclampsia
## Gestational Hypertension
#### Definition

* Diastolic blood pressure greater than 90mmHg on two recordings on the same arm greater than five minutes apart.
* Gestational hypertension must be new onset after the 20th week of gestation.

#### Epidemiology

* Affects 5% of pregnancies.
* Along with bleeding, the leading cause of maternal mortality in Canada.
* 35% risk of developing preeclampsia

## Preexisting Hypertension
#### Definition

* Hypertension in pregnant women diagnosed prior to the 20th week of gestation.

#### Epidemiology

* 25% risk of developing preeclampsia, with a 25% recurrence.

## Pre-Eclampsia
#### Definition

* Gestational hypertension with proteinuria or end organ dysfunction.
* Preexisting hypertension with resistant hypertension with new or worsening proteinuria or one or more adverse conditions.
** Resistant hypertension requires 3 or more drugs for control after 20 weeks of gestation.
** Proteinuria is suspected at a urine dipstick result >2. If this result is positive, a 24h protein collection should be done and the result will be >300mg/day. The latter test is performed to account for orthostatic proteinuria which may confound the dipstick test.
** Adverse conditions are defined as
*** BP >160/110
*** HELLP syndrome: Hemolysis, Elevated Liver enzymes, Low Platelets. Leads to placental abruption, hepatic and or renal dysfunction, preterm delivery, and death.
*** Proteinuria >5g per day
*** CNS symptoms
*** Pulmonary edema
*** Fetal growth restriction
* Severe preeclampsia is pre-eclampsia beginning before 34 weeks with 5g proteinuria per day. 20% of these women develop HELLP

#### Etiology

* Etiology unknown, but may involve vascular endothelial damage and widespread coagulation.
* Risk factors include nulliparity, >35 or <18 years of age in the mother, past history of preeclampsia or hypertension, connective tissue disease, diabetes, black, thrombophilia, antiphospholipid antibody syndrome, and mulitfetal gestation.

#### Pathophysiology

* The primary factor is vasospasm to separate end organs.
* Hematologic abnormalities include hemolysis, thrombocytopenia, and coaglulopathy secondary to hepatic dysfunction.
* Decreased renal blood flow leads to increased blood urea nitrate concentration.
* Neurological sequelae ensue: headache, visual changes, seizures from intracranial bleeding.
* Decreased blood flow to the fetus creates hypoxia, growth restriction, and oligohydramnios.

#### Clinical Presentation

* Eclampsia

#### Management

* The primary treatment for gestational hypertension and pre-eclampsia is delivery.
* If term gestation (>37 weeks), deliver the baby.
* If preterm (<34 weeks), only deliver if membranes have ruptured, if the fetal status is questionable, intrauterine growth retardation, and the fetal lungs appear mature.
** Patients should be sent to a tertiary center with high-level neonatal care.
* If adverse conditions are present
** Antihypertensive medications should be administered (target less than 160/110, but with the diastolic pressure no lower than 90 acutely)
** MgSO4
** Anesthesia
** Delivery
* MgSO4 IV bolus and infusion for eclampsia, antihypertensives, and delivery. The mother is the first priority in this circumstance.
* Delivery independent of gestational age for HELLP syndrome.
* Prevention: baby aspirin once every day; calcium 1g per day, every day.
* Magnesium Sulfate Toxicity
* May lead to cardiac arrest
* Decreased urine output
* Loss of deep tendon reflexes
* Respiratory insufficiency
* Must be treated with 10cc of 10% Calcium Gluconate STAT