Hypertension-related problems in pregnancy are classified in four ways
• Chronic hypertension
• Pregnancy – induced chronic hypertension
• Preeclampsia
• Eclampsia

The hypertension in each of these dignoses is classified as:
Mild : Systolic > 140 mmHg and/or diastolic > 90 mmHg
Severe : Systolic > 160 mmHg and/or diastolic > 110 mmHg

The only cure for hypertension in pregnancy is delivery

Pathophysiology of Hypertension in Pregnancy
Normal : Arachdonic acid triggers two pathways:
1. Prostacycline: Decreases blood pressure via: decreased vasoconstriction, Increased uteroplacental blood flow
2. Thromboxane: Increases blood pressure via: increased vasoontriction, decreased uteroplacental blood flow

In Pregnancy-Hypertensive States
The balance is thought to be tipped toward the thromboxane pathway.
Hypertension related deaths in pregnancy account for 15% of maternal deaths
Chronic hypertension and pregnancy
If during pregnandy a chronic hypertensive patient’s systolic blood pressure rises by 30 mmHg or diastolic rises by 15 mmHg, it is pregnancy induced hypertension superimposed on chronic hypertension.
Management
Mild : Early and serial ultrasounds, biophysicals
Severe : serial ultrasounds and biophysicals, antihypertensives (methyldopa/nifedipine)

PREGNANCY INDUCED HYPERTENSION
Defined as hypertension during pregnancy in a previously normotensive woman (the patient had normal blood pressure prio to 20 weeks gestation)

Subsets of pregnancy-induced hypertension
1. Pregnancy induced hypertension
2. Preeclampsia : renal involvement leads to proteinuria
3. Eclampsia : central nervous system involvement leads to seizures
4. HELLP Syndrome : the clinical picture is dominated by hematoloic and hepatic manifestations

Complication
• Heart failure
• Cerebral hemorrhage
• Placental abruption
• Fetal growth restriction
• Fetal death

Management

Mild : observe, bed rest
Severe : always hospitalize + antihypertensive pharmacotherapy (hydralazine or labetalol short term, nifedipine or methyldopa long term)
In pregnancy induced hypertension we must monitor for intrauterine growth retardation and progression to superimposed preeclampsia

Severe Pregnancy induced hypertension usually occurs in the third trimester

Generally for all pregnancy-hypertensive states:
If > 36 weeks/fetal lung maturity : Induce labor
If < 34 weeks/fetal lung immaturity : steroids plus expectant management
If fetal or maternal deterioration at any gestational age, induce labor

PREECLAMPSIA
Preeclampsia is pregnancy induced hypertension with proteinuria +/- pathological edema. It is classified as mild or severe
Preeclampsia rarely develops before 20 weeks and usually occurs in a first pregnancy
Preeclampsia is usually asymptomatic; itscrucial to pick up during routine prenatal visits

Criteria for mild preeclampsia
• Blood pressure : ? 140 systolic or ? 90 diastolic
• Proteinuria : 300 mg to 5 g/24 hrs ( normal : < 300 mg/24 hrs in pregnancy, < 150 mg/24 hrs in nonpregnant state)

Manifestations of severe disease
• Blood pressure : > 160 systolic or > 110 diastolic
• Proteinuria : 5 g/24 hrs
• Elevated serum creatinine
• Oliguria (< 500 ml/24 hrs)
• Symptoms suggesting end organ involvement (headache, visual disturbances, epigastric pain)
• Pulmonary edema
• Hepatocellular dysfunction
• Thrombocytopenia
• IUGR or oligohydramnions
• Microangiophatic hemolysis
• Grand mal seizures (eclampsia)

Predisopsing Factors
• Nulliparity
• Family history of preeclampsia-eclampsia
• Multiple fetuses
• Diabetes
• Chronic vascular disease
• Renal disease
• Hydatidiform mole
• Fetal hydrops

HELLP SYNDROME

Hellp syndrome is a manifestation of preeclampsia with hemolysis, elevated liver enzyms and low platelets. In contrast to typical presentations of preeclampsia, it is associated with :
• High morbidity
• Multiparous mothers
• Mothers older than 25
• Less than 36 weeks gestation
The prime objectives in severe cases are to forestall convulsions, prevent intracranial hemorrhage and serious damage to other vital organs, and deliver a healthy infant

Diagnosis of Preeclampsia

Once preeclampsia is suspected, the following tests should be done :
• Blood : Electrolytes, blood urea nitrogen (BUN), creatinine, liver function tests (LFTs) (ALT, AST), complete blood count (CBC), uric acid, and platelet count
• Urine : Sediment, 24 hour protein, 24 hour creatinine
• Fetal : ultrasound, nonstress test, biophysical profile

Management

Varies depending on severity of disease and gestational age of fetus:
Mild Preeclampsia
• Hospitalize, observe, bedrest, low-salt diet, monitor labs closely

Severe Preeclampsia

• Hospitalize, bed rest, low salt, low calories
• Antihypertensive pharmacotherapy: hydralazine or labetalol short term nifedipine or methyldopa long term
• Anticonvulsive theraphy : magnesium sulfate

Plus the following :
• If > 36 weeks/fetal lung maturity : induce labor
• If < 34 weeks/fetal llung immaturity : steroids plus expectant management
• If fetal or maternaldeterioration at any gestational age : induce labor
The only cure is delivery

ECLAMPSIA

Criteria : Mild or severe preeclampsia ; generalized seizures
25% of seizures are before labor, 50 % of seizures are during labor, 25% of seizures are post labor (maybe encountered up to 10 days post partum)

Management

1. Control of the convulsions (magnesium sulvate IV and IM). Magnesium toxicity is associated with loss of patellar reflexes. Treat with calcium gluconate 10% solution 1g iv
2. Correction of hypoxia and acidosis
3. Blood Pressure control (hydralazine or labetolol)
4. Delivery after control of convulsions

Antihypertensive agents used in pregnancy
Short term control : hydralazine , labetolol
Long term control : methyldopa, nifedipine, atenolol