hypertension and pregnancy(1)

8/11/2019 Hypertension and Pregnancy(1)

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Hypertension specialist ESH


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Hypertensive disorders in pregnancy:

maternal

fetal

neonatal morbidity and mortality

a major cause of


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Pregnant women with hypertension

at higher risk for

abruptio placentae

cerebrovascular events

organ failure

DIC


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Fetus at higher risk for

intrauterine growth retardation

prematurity

intrauterine death


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WHO definition of hypertension

in pregnancy

1. SBP > 140 mmHg or DBP > 90 mmHg

2. Rise in SBP > 25 mmHg or rise in DBP> 15 mmHg compared to pre-pregnancyvalues or those in the first trimester


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Definition of hypertensionin pregnancy

SBP > 140 mmHg or DBP > 90 mmHg


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Cardiovascular changes in pregnancy

SBP

DBP

MAP

HR

SV

CO

4-6 mmHg

8-15 mmHg

6-10 mmHg

12-18 BPM

10-30%

33-45%

All bottom at 20-24 wks, then rise

gradually to pre-pregnancy values at

term

Early 2nd trimester, then stable

Early 2nd trimester, then stable

Peaks in early 2nd trimester, then

until term

Parameter Timing

M ain DM , M ain EK: Obstetri cs and Gynecology, 1984


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Definition CHS NHBPEPWG WHO

Hypertension,mmHg

Severehypertension

DBP > 90

DP > 110

BP > 140/90

DP > 110 orSP > 160

BP > 140/90or riseSP > 25 and/orDP > 15 mmHg

DP > 110SP > 160

CHS = Canadian Hypertension SocietyNHBEPWG = National High Blood Pressure Education Program Working Group (US)

WHO = World Health Organization


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Definition ISSH ASSH ACOG

Hypertension,mmHg

Severehypertension

DP > 90

DP > 110

DP > 90 and/orSP > 140, or risein SP of > 25 andin DP of > 15

DP > 110 and/orSP > 170

DP > 90or SP > 140

DP > 110SP > 160-18

ISSH = International Society for Study of HypertensionASSH = Australian Society for Study of HypertensionACOG = American College of Obstetricians and Gynecologists


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Criterion CHS NHBPEPWG WHO

Korotkoffsound

Severe proteinuria(24-h urine

collection, g/d)

IV

> 3

V

> 2

IV

-

CHS = Canadian Hypertension SocietyNHBEPWG = National High Blood Pressure Education Program Working Group (US)

WHO = World Health Organization


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Criterion ISSH ASSH ACOG

IV

> 3

Korotkoffsound

Severe proteinuria(24-hr urine

collection, g/d)

IV

> 0.3 or positivedipstick result of> 2+

-

> 5

ISSH = International Society for Study of HypertensionASSH = Australian Society for Study of HypertensionACOG = American College of Obstetricians and Gynecologists


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Measurement of BP

Mercury sphygmomanometer

Both Phases IV and V to be recorded

Phase IV should be used for initiating

clinical investigation and management


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Classification of hypertensionin pregnancy

pre-existing hypertension

gestational hypertension pre-existing hypertension plussuperimposed gestational hypertensionwith proteinuria

antenatally unclassifiable hypertension


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Pre-existing hypertension

1-5% of pregnancies

BP > 140/90 mmHg predates pregnancy

or develops before 20 weeks of gestation

In most cases, hypertension persists more

than 42 days post partum, it may be

associated with proteinuria


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Gestational hypertension

Pregnancy-induced hypertension withor without proteinuria

Hypertension develops after 20 weeksgestation, in most cases, i t r esolves within42 days post par tum

Poor organ perfusion


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Antenatally unclassifiable hypertension

Hypertension with or without systemicmanifestation

BP f irst recorded af ter 20 weeks gestation,re-assessment necessary at or after 42 days

post partum


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Pre-eclampsia

Gestational hypertension associatedwith significant proteinuria

300 mg/l or 500 mg/24 h or dipstick 2+ or more

Poor organ perfusion


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Basic laboratory tests for monitoringhypertension in pregnancy

Hemoglobin and hematocrit Platelet count Serum AST, ALT, LDH Proteinuria (24-h urine collection) Urinalysis Serum uric acid

Serum creatinine


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Hemoglobinand hematocrit

Platelet count

Hemoconcentration supports diagnosis of gestationalhypertension with or without proteinuria. It indicates

severity. Levels may be low in very severe casesbecause of hemolysis.

Low levels < 100,000 x 10 9/L may suggest consumptionin the microvasculature. Levels correspond to severity

and are predictive of recovery rate in post-partum

period, especially for women with HELLP syndrome.*


* HELLP Hemolysis, Elevated Liver enzyme levels and Low Platelet count


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Serum uricacid

Serumcreatinine

Elevated levels aid in differential diagnosis ofgestational hypertension and may reflect sever ity.

Levels drop in pregnancy. Elevated levels suggest

increasing sever ity of hypertension; assessmentof 24-h creatinine clearance may be necessary.


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Serum AST,ALT

Serum L DH

Elevated levels suggest hepatic involvement. Increasing levels suggest worsening sever ity.

Elevated levels are associated with hemolysis andhepatic involvement. May reflect severity and maypredict potential for recovery post partum,especially for women with HELLP* syndrome.

* HELLP Hemolysis, Elevated Liver enzyme levels and Low Platelet count


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Urinalysis

Proteinuria(24-h ur inecollection)

Dipstick test for proteinuria has significant false-positiveand false-negative rates. If dipstick results are positive(> 1), 24-h urine collection is needed to confirmproteinuria. Negative dipstick results do not rule out

proteinuria, especially if DBP > 90 mmHg.

Standard to quantify proteinuria. If in excess of 2g/day,very close monitoring is warranted. If in excess of 3g/day,

delivery should be considered.


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Management of hypertension in pregnancy

depends on

BP levels gestational age associated maternal and fetal risk factors


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Non-pharmacologic management

SBP 140-149 mmHg or

DBP 90-99 mmHg

activity, bed rest (left lateral position)

AVOID : weight reduction and salt restriction


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Emergency management of hypertensionin pregnancy

SBP 170 or DBP 110 mmHg hydralazine, labetalol, methyldopa or nifedipine


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Thresholds for drug treatment initiation

BP > 140/90 mmHg in women

with gestational hypertension without proteinuria or pre-existing hypertension before 28 weeks' gestation or gestational hypertension and proteinuria or symptoms at any time or pre-existing hypertension and TOD or pre-existing hypertension and superimposed gestational hypertension

BP > 150/95 mmH g In all other circumstances methyldopa, labetalol, calcium antagoni sts, and beta-blockers

AVOID: ACE inhibitors, AIIA, diuretics

magnesium sulfate: eclampsia, treatment and prevention of seizures


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Br J Obstet Gynaecol 1998;105:718-22


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Antihypertensive drugs used in pregnancy

Women with pre-existing hypertension are advised

to continue their current medication except for ACE

inhibitors and AIIA


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Central alf aagonists

Beta-blockers

Alfa-/beta-blockers

Methyldopa is the drug of choice.

Atenolol and metoprolol appear to be safe and effective

in late pregnancy.

Labetalol has comparable efficacy with methyldopa,in case of severe hypertension, it could be given

intravenously.


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Calcium-

channel blockers

ACE inhibitors,

angiotensin I I

antagonists

Oral nifedipine or i.v. isradipine could be given

in hypertensive emergencies. Potential synergism

with magnesium sulfate may induce hypotension.

Fetal abnormalities including death can be caused

and these drugs should not be used in pregnancy.


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Diuretics

Direct

vasodilators

Diuretics are recommended for chronic hypertension

if prescribed before gestation or if patients appear to

be salt-sensitive. They are not recommended in

pre-eclampsia.

Hydralazine is no longer the parenteral drug of choice;

perinatal adverse effects.


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Breast-feeding

Does not increase BP in nursing mothers

All antihypertensive agents taken by the nursing

mother are excreted into breast milk; however,most of them are present at very low concentrations,except for propranolol and nifedipine concentrations,which are similar to maternal plasma

Implications of hypertension in pregnancy


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Implications of hypertension in pregnancy

P th h i l i f t i l d i l i


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Pathophysiologic factors involved in preeclampsia

Classification of hypertensive disorders of pregnancy


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Chronic hypertension BP 140/90 mm Hg before the 20th week of gestation

Preeclampsia Elevated BP ( 140/90 mm Hg) in a patient who was normotensivebefore 20 weeks of gestation, accompanied by

Urinary excretion of 0.3 g of protein in a 24-h collectionOther features that increase the certainty of the diagnosis of

preeclampsiaBP 160/110 mm HgProteinuria 2.0 g/24 h that appears initially during pregnancy and

regresses postpartumNewly-elevated serum creatinine concentration ( 1.2 mg/dL)

Platelet count 100,000/mm 3 and/or evidence of microangiopathichemolytic anemia

Elevated hepatic enzymes (ALT or AST)

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Preeclampsia superimposed upon chronic hypertension (which

carries a worse prognosis than either condition alone) is more likely with

one or more of the following:

New onset proteinuria ( 0.3 g/24 h)

Hypertension and proteinuria before 20 weeks of gestation

Sudden increase in proteinuria

Sudden increase in BP, despite previous good control

Thrombocytopenia (platelets 100,000 mm 3)

Increase in ALT or AST to abnormal levels



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Eclampsia

Occurrence of seizures that cannot be attributed to other causesin a patient with preeclampsia

Gestational hypertension Transient hypertension of pregnancy (if preeclampsia is not

present at time of delivery and BP returns to normal by 12 weekspostpartum)

Chronic hypertension (if the elevated BP seen during pregnancypersists longer than 12 weeks postpartum)

yp p g y

Management of hypertension in pregnancy


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g yp p g y

Drug therapy for hypertension in pregnancy


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RecommendedMethyldopa initial drug of choice against which all otherantihypertensive agents must be tested; used for the longest timein the treatment of hypertension in pregnancy, so it has the bestlong-term follow-up data supporting its lack of toxicity; also lowersthe number of midtrimester abortions in hypertensive womencompared with placeboHydralazine used extensively, usually with methyldopa, andconsidered safe for mother and fetus by most obstetricians-blockers (typically atenolol or labetalol) used with caution and

concern about growth retardation, fetal bradycardia, and the abilityof the fetus to withstand hypoxic stress

Nifedipine teratogenic in rats (at 30 the recommended dose inhumans); sometimes acutely used in preterm labor, but withoutFDA approval

Drug therapy for hypertension in pregnancy


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g py yp p g y

Not recommended

Diuretics cause volume depletion, which has been associated withpoor fetal outcomes

ContraindicatedACE inhibitors or angiotensin II receptor antagonists associated

with lethal acute renal failure in neonates of women treated in the

third trimester

Relative risk of preeclampsia: calcium supplementation vs placebo


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Preeclampsia: efficacy of anti-platelet agents vs placebo


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INCIDENCE OUTCOME ANTIPLT. AGENTS VS PLCB RR(95% CI)

Pregnancy-induced hypertension795/8464 (9.4%) 810/8450 (9.6%) 0.96 (0.88 1.05)

Proteinuric preeclampsia951/13,991 (6.8%) 1110/13,973 (7.9%) 0.85 (0.79 0.93)

Preterm delivery1772/13,473 (13.1%) 1928/13,534 (14.2%) 0.92 (0.87 0.97)

Fetal, neonatal, or infant death

361/14,325 (2.5%) 407/14,353 (2.8%) 0.88 (0.77 1.01)Small for gestational age

668/9439 (7.1%) 701/9448 (7.4%) 0.94 (0.85 1.04)

hypertension and pregnancy(1)

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