Hypertension in Pregnancy

1. Hypertension in Pregnancy Dapinderjit Gill Ross University MS3

2. Gestational HTN • Transient HTN of pregnancy • Preeclampsia • Mild • Severe • Eclampsia • Chronic HTN preceding pregnancy • Chronic HTN with superimposed pregnancy-induced hypertension • Superimposed preeclampsia • Superimposed eclampsia Hypertension Disorders in Pregnancy Classification of the American College of Obstetricians and Gynecologists

3. Gestational Hypertension

4. Gestational HTN • sustained systolic blood pressure at or above 140mmHg, or a diastolic blood pressure of 90mmHg or greater • increase in BP must be present on at least two separate occasions, 6 hours or more apart • HTN in late pregnancy (>20 weeks gestation) in the absence of other findings suggestive of preeclampsia • if BP returns to baseline by 12 weeks postpartum = dx. of Transient hypertension of pregnancy

5. Gestational HTN • 5-10% of pregnancies that proceed beyond 1st trimester develop gestational HTN • increased incidence of up to 30% in multiple gestation • 15-25% of women initially diagnosed with gestational HTN develop preeclampsia • Earlier onset of gestational HTN are more likely to progress to preeclampsia

6. PathophysiologyChanges seen in patients • Cardiovascular effects • Elevated BP • Increased cardiac output • Hematologic effects • Third spacing of fluid due to increased blood pressure and decreased plasma oncotic pressure • Renal effects • Atheroscleroticlike changes in renal vessels (glomerular endotheliosis)  decreased glomerular filtration rate and proteinuria • Uric acid filtration is decreased

7. PathophysiologyChanges seen in patients • Neurologic effects • Hyperreflexia/hypersensitivity (does not correlate with severity of disease) • In severe cases, grand mal seizures • Pulmonary effects • Pulmonary edema may occur due to decreased colloid oncotic pressure • Fetal effects (severe gestational HTN) • Vasospasm  Decreased intermittent placental perfusion  IUGR, oligohydramnios, low birth weight

8. PathophysiologyMechanisms • Uterine vascular changes • Trophoblastic-mediated vascular changes  decreased musculature in spiral arterioles  development of low resistance, low pressure, high-flow system • Inadequate maternal vascular response • Endothelial damage is also noted within the vessels • Hemostatic changes • Increased PLT activation with increased endothelial fibronectin and decreased antithrombin III and alpha-2-antiplasmin  further endothelial damage is thought to promote further vasospasm

9. PathophysiologyMechanisms • Changes in prostanoids • During pregnancy, both PGI2 (vasodilation and decreased PLT aggregation) and TXA2 (vasoconstriction and PLT aggregation) are increased with balance favored to PGI2 • In preeclampsia, TXA2 is favored • Changes in endothelium-derived factors • Decrease in Nitric oxide promoting vasoconstriction

10. Gestational HTN • Mild: outpatient with weekly visits, bed rest • Antihypertensive therapy: • Indicated if diastolic pressure is repeatedly above 110mmHg • Hydralazine (Apresoline) 5mg increments IV until acceptable BP is obtained (diastolic pressure to 90-100mmHg range) • Other medications that can be used in pregnancy (oral): • methyldopa 250mg BID/TID max 3g/day • Labetalol 100mg max 2400mg/day • Nifedipine 30-60mg max 120mg/day • Magnesium sulfate in severe gestational HTN for seizure prophylaxis

11. Chronic Hypertension

12. Chronic HTN • HTN present before 20th week of gestation or beyond 6 weeks postpartum (>12 weeks postpartum from uptodate.com) • 15% of gestational HTN cases go on to develop chronic HTN • 25% risk of developing superimposed preeclampsia or eclampsia • Close monitoring of maternal BP and follow appropriate fetal growth and well-being • Pt. should be encouraged to increase the amount of time she rests

13. Preeclampsia

14. Preeclampsia • Development of HTN with proteinuria induced by pregnancy generally in the second half of gestation • More frequent at the extremes of reproductive years • More common in women who have not carried a previous pregnancy beyond 20 weeks old women or young lady?

15. Preeclampsia • Mild: • BP: systolic > 140mmHg and/or diastolic > 90mmHg • Proteinuria: >300mg on 24h collection of +1 on single sample • Severe: • BP: systolic > 160-180mmHg and/or diastolic > 110mmHg • Proteinuria: >5g on 24h collection or +2 on single sample • Multisystem alterations: cerebral or visual disturbances, oliguria, pulmonary edema, cyanosis, epigastric or right upper quadrant pain, thrombocytopenia

16. Preeclampsia

17. Preeclampsia • Mild preeclampsia • If immature fetus  bed rest mainly in lateral decubitus position • HTN therapy if needed • Severe preeclampsia • Magnesium sulfate 4g loading dose with 1-3g/hr infusion rate • Antihypertensive therapy • Induction or cesarean delivery • fetal pulmonary maturity depending on gestational age should be considered (>=34weeks)

18. Eclampsia

19. Eclampsia • addition of convulsions in a woman with preeclampsia • occurs in 0.5-4% of deliveries • most cases occur within 24h of delivery with about 3% of cases diagnosed between 2-10 days postpartum • 25% have eclamptic seizures before labour, 50% during labour, and 25% after delivery

20. Eclampsia • Anticonvulsant therapy • Diazepam or similar drugs • Magnesium sulfate to prevent further seizures • Maintain adequate airway, oxygenation, restraining gently as needed and inserting a padded tongue blade

21. HELLP Syndrome

22. HELLP Syndrome • HTN patients with hemolysis (H), elevated liver enzymes (EL), low platelet count (LP) • 4-12% of pt. with severe preeclampsia and eclampsia develop HELLP syndrome • first sx. often missed: nausea, emesis, and non-specific viral-like syndrome HELLP!

23. HELLP Syndrome Treatment: • cardiovascular stabilization, correction of coagulation abnormalities, and delivery • PLT transfusion before or after delivery if PLT count is <20,000/mm3(advised at <50,000/mm3before cesarean) • <32 weeks gestation; steroid therapy may help stabilize maternal PLT count

24. Thank You!

25. References Beckmann, Charles R.B., Ling, Frank W., Smith, Roger P., Barzansky, Barbara M., Herbert, William N.P., Laube, Douglas W. “Obstetrics and Gynecology”. 5th edition Lippincott Williams & Wilkins. pp. 188-196 Magloire, Lissa etc. “Gestational Hypertension”. May 2011.<uptodate.com> August, Phyllis et. al. “Management of hypertension in pregnancy and postpartum women”. May 2011 <uptodate.com>