HYPERTENSIVE DISORDERS OF PREGNANCY

Dr. Dianne MP Graham, MD, CCFPBased on Guidelines From SOGC ALARM Course

& WHO Guide on Managing Complications in Pregnancy and Childbirth

• Fourth leading cause of maternal death in pregnancy

• Those that survive can have major end organ damage such as stroke, kidney or hepatic failure

• Major cause of fetal morbidity such as IUGR, prematurity and fetal hypoxia

Why Recognize and Treat Hypertensive Disorders of Pregnancy?

DEFINITIONS

• 1. Chronic Hypertension (Onset before 20 weeks gestation.)

• 2. Chronic Hypertension with Superimposed Mild pre-eclampsia

• 3.Pregnancy Induced Hypertension• 4. Mild Pre-eclampsia• 5. Severe Pre-eclampsia• 6.Eclampsia

CHRONIC HYPERTENSION MANAGEMENT

• Diastolic blood pressure 90 mm Hg or more before first 20 weeks of gestation

• Encourage additional periods of rest• Do not lower blood pressure below pre-pregnancy

levels……higher levels of BP maintain renal and placental perfusion

• If patient was on anti-hypertensive meds before pregnancy continue them as long as they’re considered safe in pregnancy or switch to ones that are safe

CHRONIC HYPERTENSION MANAGEMENT

• If diastolic BP is 110 mm Hg or more treat with anti-hypertensive drugs

• If PROTEINURIA (urine protein dipstick 1+ or more) treat for Pre-eclampsia

• Monitor fetal growth & condition• If there are no complications deliver at term• If pre-eclampsia develops treat as for mild or

severe pre-eclampsia

PREGNANCY INDUCED HYPERTENSION

• Two readings of diastolic BP 90-110 Hg 4 hours apart after 20 weeks gestation

• No proteinuria • In PIH there may be NO symptoms and the only sign may

be hypertension• Monitor mother weekly for BP, urine protein and

educate patients and family to ominous symptoms• Monitor fetal growth and well being weekly• Treat with medication if BP is >110 mmHG• Do not restrict salt

MILD PRE-ECLAMPSIA

• Two readings of diastolic BP 90-110 mmHg 4 hours apart after 20 weeks gestation

• Proteinuria up to 2+• Mild pre-eclampsia can progress rapidly to

severe pre-eclampsia…..monitor closely• Educate patient and family as to signs of

severe pre-eclampsia and eclampsia

MANAGEMENT OF MILD PRE-ECLAMPSIA < 37 WEEKS

• Monitor BP, urine (for proteinuria), reflexes and fetal movement twice a week as an outpatient if signs remain unchanged or normalize

• Counsel woman and her family as to danger signs of severe pre-eclampsia or eclampsia

• Encourage additional periods of rest• Encourage woman to eat a normal diet. Do NOT advise

salt restriction• Do NOT give anti-convulsants, antihypertensives,

sedatives or tranquilizers.

MANAGEMENT OF MILD PRE-ECLAMPSIA < 37 WEEKS AS IN PATIENT

• Provide normal diet (No salt restriction)• Monitor BP (twice daily) • Monitor urine for proteinuria (once a day)• Do not give anticonvulsants, antihypertensives or

sedatives unless BP rises or urinary protein level increases.

• Do not give diuretics. They are harmful and should only be used in pre-eclampsia with signs of pulmonary edema or heart failure

MILD PRE-ECLAMPSIA <37 WEEKS MANAGEMENT AS OUTPATIENT

• If diastolic BP decreases to normal in hospital & condition remains stable she can be sent home

• Advise to rest and watch out for significant signs of severe pre-eclampsia

• See her twice a week to monitor BP, urine for proteinuria and fetal condition and to assess for symptoms and signs of severe pre-eclampsia

• If diastolic BP rises again readmit her

SIGNS OF SEVERE PRE-ECLAMPSIA

• Central Nervous System: Frontal headache, visual disturbance, tremulousness, irritability, somnolence, seizures

• Renal: Proteinuria, oliguria<500 ml/24 hour• Hepatic: severe nausea & vomiting, RUQ/Epigastric

pain• Hematologic: bleeding, petechiae, decreased platelets• Vascular: diastolic BP >110 or pulmonary edema, non-

dependant edema

SEVERE PRE-ECLAMPSIA

-Diastolic BP of 110 mmHg or more after 20 weeks gestation

-Proteinuria 3+ or more-Management is always active not expectant -Severe pre-eclampsia can progress to eclampsia

rapidly and is not related to how high the BP is-In severe pre-eclampsia delivery should occur in

24 hours.

ANTI-HYPERTENSIVE THERAPY GOALS

• If diastolic BP is 110 mm Hg or more give anti-hypertensive drugs

• The goal is to keep diastolic BP between 90 mm Hg and 100 mm Hg to prevent cerebral hemorrhage

• Helps maximize maternal safety for safe delivery

ANTIHYPERTENSIVE DRUGS ACUTE

• Administered by IV route• Hydralazine is drug of choice (arteriolar dilator)

–Dosage: 5 mg IV test dose slowly over 5 minutes followed by 5-10mg IV q20 minutes until BP is lowered. Repeat hourly as needed or give hydralazine 12.5 mg I.M. every two hours as needed.

• Severe hypotension may occur with hydralazine if patient is hypovolemic

ANTIHYPERTENSIVE DRUGS ACUTE

• If hydralazine is not available , give labetolol or nifidepine

• Labetolol Dosage: 10 mg IV• If response to Labetolol inadequate (diastolic BP

remains above 110mm Hg) after 10 minutes give Labetolol 20 mg IV

• Increase dose of to 40 mg and then 80 mg if satisfactory response is not obtained after 10 minutes of each dose

ANTIHYPERTENSIVE DRUGS ACUTE

• Nifedipine : Dosage: 5 mg under the tongue• If response to nifedipine is inadequate

(diastolic BP remains above 110 mm Hg after 10 minutes, give an additional 5 mg under tongue

• CAUTION: Magnesium toxicity can occur with combining nifedipine with MgSO4

ANTIHYPERTENSIVE DRUGS ORAL

• For maintenance in cases of chronic hypertension, gestational hypertension and mild pre-eclampsia

• Aldomet (alpha-methyl-dopa) Dosage: 500 mg to 1000 mg bid to qid. Maximum dose 3000 mg daily

• Labetolol Dosage: 200 to 600 mg bid to tid• Nifedipine Dosage: 20 to 40 mg bid

SEIZURE PROHYLAXIS

• Difficult to predict who will seize. • Seizures not directly related to degree of

hypertension or level of proteinuria• Magnesium Sulfate is drug of choice when

seizure prophylaxis is indicated. Dosage:4 gm IV followed by 1-2 g/hour IV

• MgSO4 is superior to phenytoin or diazepam in prophylaxis and treatment of seizures in pregnancy

ECLAMPSIA

• Convulsions• Diastolic BP 90 mm Hg or more after 20 weeks

gestation• Proteinuria of 2+ or more• Coma• Clonus

MANAGEMENT OF ECLAMPSIA

• Call for help• Maternal left lateral position• Protect the airway• Establish IV access of Normal saline or Ringers• MgSO4• Post-Seizure: airway, oxygen, vital signs, fetal surveillance• assess for signs of abruption

MAGNESIUM SULFATE

• Loading Dosage: Give 4 gm of 20% magnesium sulfate IV over five minutes

• Follow promptly with 10 gm of 50% MgSO4 solution. Give 5 gm in each buttock as a deep IM shot with 1 ml of 2%lignocaine in the same syringe. Warn patient that a feeling of warmth will be felt when MgSO4 is given.

• If convulsions recur after 15 minutes give 2 gm of 50% MgSO4 IV over 5 minutes

MAGNESIUM SULFATE

• Maintenance Dose: Give 5 Gm of 50% MgNO4 with 1 ml of 2% lidocaine in same syringe by deep IM injection every four hours. Continue this treatment for 24 hours after delivery or the last convulsion (whichever occurs last)

• If 50% solution is not available give 1 gm of 20% MgSO4 solution IV every hour by continuous infusion

TOXICITY SIGNS FROM MAGNESIUM SULFATE

• Closely monitor the woman for signs of toxicity

• WITHHOLD OR DELAY DRUG IF:• Respiratory rate falls below 16 per minute• Patellar reflexes are absent• Urinary output falls below 30 ml per hour over

preceding four hours

MAGNESIUM SULFATE TOXICITY MANAGEMENT

• KEEP ANTIDOTE READY• In case of respiratory arrest:• Assist ventilation (mask and bag, anaesthesia

apparatus, intubation)• Give Calcium Gluconate 1gm (10 ml of 10%

solution) IV slowly until calium gluconate begins to antagonize the effects of magnesium sulfate and respiration begins.

REMEMBER

• 50% of patients seize before delivery• 25% seize during delivery• 25% of patients seize in the first 24 hours

AFTER delivery

• NEVER use ergometrine in patients with gestational hypertension or pre-eclampsia as it increases risk of seizures!!!!

DELIVERY- THE CURE

• Timely delivery minimizes morbidity and mortality• Stabilize mother before delivery• Delay delivery to gain fetal maturity only when

maternal and fetal condition allows• Gestational hypertension is a progressive disease• Expectant management is potentially harmful in

presence of severe disease or suspected fetal compromise

PERI AND POSTPARTUM MANAGEMENT

• Avoid abrupt drop in BP – aim for 80 -100 mm Hg diastolic

• Avoid fluid overload• Patient MUST be monitored closely after

delivery