HYPERTENSIVE DISORDERS OF PREGNANCY Dr. Dianne MP Graham, MD, CCFP Based 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 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 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 mm Hg diastolic Avoid fluid overload Patient MUST be monitored closely after delivery