By:Dr. Nik Harlina Roza Nik Kazim 4th year Family Medicine

Topics coveredScope of the problemScreening of Hpt in pregnancyAssessment of Hpt motherAntihypertensive when to start - aim of treatmentUse of oral antihypertensiveEclampsia Role of anti-convulsion - MgSo4When to deliverIndication of referal

I

Introduction Scope of problemCommonest medical problem in pregnancy.

Complicates 10-15% pregnancies in most developed countries.

Eclampsia occurs in about 1-2% of women with pre-eclampsia.

Introduction Major contributing factor to maternal death. Main cause of maternal mortality in UK 1996.

Death rate is about 2%.

Introduction-MalaysiaHDP accounts 7-10 % of admission.

The prevalence of HDP in Malaysia 23.3 per 1000 livebirths

Incidence rate of eclampsia has fallen from 0.73 per 1000 livebirths in 1991 to 0.44 per 1000 livebirths in 1998 in Peninsular Malaysia.

Introduction

Rate of eclampsia & maternal mortality reduced not only related to acute management but.

-Screening and intervention -Organized ANC (appropriate tx & surveillance) -Improved health community

DEFINITIONISSHPACOGMALAYSIAN CPG

Hypertension In PregnancyDiagnosis : ISSHP International Society for The Study Of Hypertension in Pregnancy.

On the basis of the diastolic blood pressure

Hypertension is defined as either :One measurement of DBP of 110 mm Hg or more OR2 consecutive measurements of DBP of 90 mm Hg or more 4 hours apart

Definition Why DBP 90 mmHg ?SBP or MAP does not add to the prognostic significant

A DBP of 90 mm Hg corresponds to the point at which the PNMR begins to rise in population studies

Definition - ACOG ACOGAmerican College Of Obstetrician & Gynaecologist ( Davis 1972 )

SBP rise >30 mm Hg or DBP > 15mmHg from 2nd TM valueHighly sensitive But lacks specificity

Definition - ACOG WHY ?In normotensive pregnancies,73% increase DBP by 15mmHg57% increase DBP by 20 mm Hg

Mac Gillivray I et all 1969 & Villar MA et all 1989

Definition - Malaysian CPG for HDPUse both systems.

Applicable to all health facilities.

Definition - Proteinuria In PregnancyBased on either :Total protein in 24H urine collection. 300 mg (0.3 g) or more. or 1 gm/L in 2 randomly collected urine samples 6 hrs apart

RISK FACTORS

Predisposing FactorsPrimigravidaGeneticMedicalSocio-economicObstetricAge

Predisposing FactorsPrimigravidityIncidence of PE in a first pregnancy = 6 %Overall incidence in 2nd pregnancy = 2 % WHY ? Immunity to the spermatozoa

Predisposing factorsGeneticMore likely in pt. with family history of PE or HT =mother with ht 20-25% risk =sister with hypertension 35-40 % risk.History of other CVD or autoimmune dis.

Medical Pre-existing HT and DM , migraine or Raynaud Phen, Chronic Renal Dis and anti Phospholipid

Predisposing factorsSocio-economicIncidence increase in low socio-economicIncidence reduced in smokers

ObstetricMultiple pregnancy , molar and hydrops fetalis

Age > 40 years

CLINICAL EFFECT

Clinical effectsEffects on mother CCF & Pulm EdemaCerebral haemorrhageRenal failureDIVCEclampsiaMaternal death

Clinical effectEffect on fetusMaternal vascular spasm lead to reduce placenta perfusion.Increase PNM x 2IUGRAbruptioFetal distressPrematurity - 30 % less than 32 week

ASSESMENT OF HPT

MATERNAL SURVEILLANCEFETAL SURVEILLANCE

Maternal surveillanceMonitoring of BP, urine for protein

Weight gain

Monitoring sign & symptoms of impending eclampsia

Biochemical investigations

Monitoring - Laboratory D(x)Serum uric acid > 350 micromol / L ( rising trend is important)Rise in serum urea & creatinine. serum urea >5 micromol / L serum creatinine > 100 mmol / L Serum transaminase Rising levels suggest severe preeclampsia with hepatic involvement

Hemoglobin & hematocrit Hemoconcentration supports d(x) of preeclampsia and indicator of severity. Values may be decreased, however, if hemolysis accompanies the disease.

Platelet count Thrombocytopenia < 100 x 1000microlitre suggests severe preeclampsia.

Quantification of protein excretion Pregnancy hypertension with proteinuria should be considered preeclampsia (pure or superimposed) until proved otherwise.

Serum albumin, LDH, blood smear and coagulation profile Values indicate extent of endothelial leak (albumin), presence of hemolysis (LDH increase, schistocytosis, spherocytosis) and possible coagulopathy.

Fetal SurveillanceFundal height / maternal weight gainFetal heartFetal movement chartCTGSerial U/S for growth fetal biometry (B.P.D / F.L / A.C) Amniotic fluid index Anomaly scan

TREATMENT

When to start treatment ???Aim of treatment ???Exact level to start tx is still controversial syst levels > 140-170 diast levels > 90-110 treatment mandatory b.p > or = 170/110

Above a certain MAP, loss of cerebral auto regulation and mother is at risk of cerebral haemorrhage.

Target b.p not to jeopardize uteroplancetal circulation. MAP aim at ,125mmHg eg 150/100

CHOICES OF ANTI-HYPERTENSIVES

DRUG INDICATION STARTING DOSE MAX DOSE CI

Methyldopa 1st line 250 mg b.d 1 gm tds Depression

Nifedipine 2nd line 10 mg b.d 40 mg bd -

Hydralazine 2nd line 25 mg tds 75 mg qid -

Labetalol 2nd line 100 mg b.d 500 mg tds Asthma (1st line in 3rd trimester)

Beta blockers 3rd line 80 mg bd 120 mg qid Asthma (eg oxprenolol)

Alpha blockers 3rd line 1 mg tds 5 mg qid -(eg prasozin)

All are safe in breast feeding

Ideal Antihypertensive - ???

Methyldopa : safe

Long experience and reassuring - long term follow-up of children expose in utero. ( Cockburn 1982 )

MethyldopaSlow onset of action. Started after 4 to 6 hours and max by 12 to 24 H.

Side effect : depression sedation lupus like syndrome blood dyscrasias liver dysfunction

Disadvantage : CI in severe PE with hepatic Cx

Labetolol- alpha adrenergic & B blockerFaster action, third choice, may be 1st in 3rd trimester

Side effects : Complete heart block / bronchoconstriction Onset of tremulousness a/w IUGR ( Sibai 1987 ) not substantiated in RCT Impaired neonatal defense mechanism

Conclusion : Maternal B blockade with Labetolol is as save as Methyldopa for the fetus and the newborn.

Calcium Channel BlockersNifedipine

2nd line therapy (add on or replace methyldopa) Swallowed capsule - peak action in 60 minsEffective within 10-15 mins due to powerful vasodilator effect.The higher the BP the greater the effectAbility to maintain cerebral blood flowSide effect headache - facial flushing - oedema

Acute Severe HypertensionSublingual Nifedipine not advisable now.

Oral methyldopa, labetolol & nifedipine is effective

Insufficient trial regarding oral medication

If failed oral medication IV labetolol / IV hydralazine is recommended

ECLAMPSIA

Management of severe PE / IE & EclampsiaControl of severe PE & IE can abort eclampsia - appropriate and adequate anticonvulsant and anti-HT (20 % eclampsia occurs with normal B.P)Sibai 1981 - S & S of IE present in 80% of case.

EclampsiaEtiology of EclampsiaUnknown - Cerebral vasospasm or edemaCerebral edema ( Chesley 1978 )Cerebral vasospasm ( Sheehan 1980 )

Drugs To Control Convulsions -

Regime 1 IV Valium

Regime 2 Magnesium sulphate

Regime 3 Iv Valium / Phenytoin

The Collaborative Eclampsia TrialNo of Pt : 1687International multicentre randomized trial comparing standard convulsion regimen Primary measure - recurrent convulsion and maternal death. MgSO4 (453) Vs Diazepam (452) (388) Vs Phenytoin (387)

MgSO4 Vs Diazepam52% lower risk of recurrent convulsion in MgSO4 group (significant).

MgSo4 Vs Phenytoin67% lower risk of recurrent convulsion in MgSO4 group (significant)

Conclusion :Evidence favor MgSO4 rather than Diazepam or Phenytoin for the Rx of eclampsia.

MgSo4

Popular for many decadeDrug of choice following recent randomized trialEffective cerebral depression. Best reduce neuromuscular irritabilityUse for severe PE, IE or Eclampsia2 methods of administration :IV or IM

Mg SO4 - I.M Regime Pritchard 1975

MgSO4 IV Therapy Zuspan 1966

Monitoring

a) -Knee jerk hourly or before each IM injection b) -RR > 16 - every 15 mins c) -U/O > 25 cc / H every hour d) -Serum Mg BD - not required now unless failure of treatment.(1.7-3.5 mmol/l)

Antidote : 10cc of 10% Ca Gluconate IV over a period of 3 mins

DELIVERY

Definitive Treatment - delivery

Is to deliver the baby

Timing of delivery depends on :Availability of NICU and infant salvage ratePresence of unacceptable risk to motherPresence of fetal compromise

TreatmentLess 30 week / baby less 1 kg :low salvageable rate

30-34 week :severe PE - deliver after Dexa , booked ventilator & full explanation to parents.Deliver after 48 H of dexa 12 mg X 2 doses.

Treatment34-37 week : severe PE - delivery should be considered

Term pregnancyDelivery is always appropriateCx favorable - delivery Cx not favorable - can wait till 40 week if : BP not high minimal proteinuria no maternal or fetal compromise

TreatmentMode of delivery :VD is generally preferable to LSCS even with manifestation of severe disease.Age, BOH, parity, Hx of infertility, fetal and maternal condition Less than 34 LSCSMore than 34 prefer VD.

INDICATION FOR REFERALAdmission indicated when:Maternal causes 1) Monitor and stabilize the blood pressure 2) In ability to control b.p despite nearly max doses of 2 antihypertensive drugs 3) Rapid rising biochemistry and haematology index 4) Pre eclampsia / Eclampsia

Fetal causes Fetal distress, IUGR, oligo - hydramnios