CME Hypertension in Pregnancy & Management

Refresher CME on hypertension in pregnancy

1. Hypertension
in Pregnancy
A Revision on the Basics
Nor Zaihan Binti Muhamad Yusof (RPh. 21540)

2. Navigating
the Session
Pathophysiology01
Management03
Clinical Values02
Drugs of Choice04

3. Physiological Changes in
Pregnancy
Hormonal Changes
Increased level of estrogen
and progesterone
Circulatory Changes
Increased vasodilation
Cardiovascular
Changes
Increased heart rate and
cardiac output
Blood Pressure = Cardiac Output X Total Peripheral
Resistance
Pathophysiology01

4. Pathophysiology01
Sanghavi, M. and Rutherford, J.D. (2014) ‘Cardiovascular physiology of pregnancy’, Circulation,
130(12), pp. 1003–1008. doi:10.1161/circulationaha.114.009029.
1.

5. Mechanism of Hypertension
in Pregnancy
Pathophysiology01
2. Granger, J.P. et al. (2001) ‘Pathophysiology of hypertension during preeclampsia linking placental ischemia with
endothelial dysfunction’, Hypertension, 38(3), pp. 718–722. doi:10.1161/01.hyp.38.3.718.
An initiating event in PIH has been postulated to
be reduced placental perfusion that leads to
dysfunction of the maternal vascular
endothelium by mechanisms that remain to be
defined.
Endothelial dysfunction will stimulate the
release of Endothelin-1 (vasoconstrictor) and
Thromboxane (vasoconstrictor)
Endothelial dysfunction will also reduce the
release of Nitric Oxide (vasodilator) and
Prostaglandins (vasodilator)
1.
2.
3.

6. Clinical Values
Hypertension in Pregnancy

7. Blood Pressure of 140/90mmHg taken after a period of rest on two
occasions
OR
Rise of systolic blood pressure (SBP) of 30mmHg and/or a rise in diastolic
blood pressure (DBP) of 15mmHg compared to pre pregnancy levels.
HYPERTENSION IN
PREGNANCY SEVERITY
SBP (mmHg) DBP (mmHg)
Mild 140 - 149 90 - 99
Moderate 150 - 159 100 - 109
Severe > 160 > 110
Hypertension in Pregnancy
Clinical Values02

8. 3 Classifications of
Hypertension in Pregnancy
Pregnancy
Induced
Hypertension
(PIH)
Hypertension after
the 20th week of
pregnancy in a
previously
normotensive
woman.
Chronic
Hypertension
Hypertension of at
least 140/90 before
20 weeks of
pregnancy OR
beyond 6 weeks
postpartum.
Chronic
Hypertension
with
Superimposed
Preeclampsia
Development of PE in
women who have
pre-existing
hypertension
Clinical Values02

9. Preeclampsia
(PE)
PIH with proteinuria
Gestational
Hypertension
(GH)
PIH without proteinuria
Pregnancy Induced
Hypertension (PIH)
Clinical Values02
Eclampsia
PIH with convulsions

10. Hypertension in Pregnancy
Clinical Values02
3. American College of Obstetricians and Gynecologists. Hypertension in pregnancy. Accessed at:
http://www.acog.org/Resources-And-Publications/Task-Force-and-Work-Group-Reports/Hypertension-in-Pregnancy

11. Management
Hypertension in Pregnancy

12. Mild - Moderate
Pregnancy
Induced
Hypertension
(PIH)
GOAL OF THERAPY
To prolong the pregnancy to as near term
as possible provided there are no
evidence of maternal complications or
fetal compromise (fetal distress,
intrauterine growth restriction (IUGR) or
oligohydramnios).
CRITERIA FOR OUTPATIENT TREATMENT
BP ≥140/90mmHg but less than 160/100mmHg.
No proteinuria.
No signs/symptoms of impending eclampsia.
No excessive weight gain.
No signs of intrauterine growth retardation.
Normal biochemical investigation.
TREATMENT
Not all mild HDP require antihypertensive treatment. A
majority of them may benefit from adequate rest.
Patients with BP of 140/90mmHg without any complications
may not require antihypertensive treatment.
Antihypertensive treatment may be considered when
diastolic BP is persistently above 100mmHg.
In all cases, care should be taken to avoid reducing the
blood pressure below the lower limits (110/80mmHg) which
would lead to a risk of placental underperfusion.

13. Mild - Moderate
Pregnancy
Induced
Hypertension
(PIH)
CRITERIA FOR INPATIENT TREATMENT
symptomatic patients.
maternal or fetal complications.
persistent diastolic blood pressure >100mmHg or
systolic >160mmHg for stabilization.
abnormal biochemical PE profile.
presence of severe proteinuria >2+.
TREATMENT
Alpha-Methyldopa or
Labetalol
In moderate HDP, the following antihypertensive drugs may be
considered:
Start with monotherapy and increase gradually till maximum
dose.

14. Mild - Moderate
Pregnancy
Induced
Hypertension
(PIH)
PREVENTION OF PRE-ECLAMPSIA
1. Calcium Supplementation
2. Low Dose Aspirin
3. Other Supplementation
Extracellular ionised calcium concentrations are crucial for
production of endothelial nitric oxide (NO) and regulation of
vascular tone. Decreased NO is implicated in pathophysiology of
pre-eclampsia
The WHO recommends calcium 1.5g to 2g daily for pregnant
women with low dietary calcium intake.
Aspirin blocks the production of certain eicosanoids by inhibition
of action of cyclo- oxygenase (COX)
Dietary supplementation of fish oil (rich in omega-3
polyunsaturated fatty acids) was considered to correct
thromboxane/prostaglandin ratios and consequently influence
vascular sensitivity BUT it is unclear whether they decrease
incidence of pre-eclampsia.
Zinc and magnesium supplements have also been considered
but the evidence is not strong

15. Severe
Pregnancy
Induced
Hypertension
(PIH)
CRITERIA FOR INPATIENT TREATMENT
SBP ≥160mmHg or DBP ≥110mmHg on two occasions 6
hours apart.
Proteinuria of 3+ or >3g/L.
Oliguria (<400ml/24 hours).
Headache
Pulmonary oedema.
Impaired liver function tests.
Increased serum creatinine (>1.2mg/dl).
Retinal haemorrhage, exudates or papilloedema.
TREATMENT
IV MgSO4 4g diluted in normal saline slow bolus if not
given earlier. This is followed by maintenance IV infusion of
MgSO4 1g per hour to prevent eclampsia
If the diastolic BP ≥110mmHg, hydralazine infusion should be
started: 20mg in 500ml of NS or Hartman’s solution, starting
at 5dpm and increasing by 5dpm every 15 minutes until the
diastolic BP is about 90mmHg.
Upon hospitalization:
GOAL OF THERAPY
To prevent a cerebro-vascular accident to
the mother whilst trying to achieve a
clinically useful prolongation of the
pregnancy

16. Eclampsia
CRITERIA TO MONITOR FOR POSSIBLE ECLAMPSIA
Severe frontal headache
Vomiting
Blurring of vision
Epigastric pain
Hyper-reflexia
TREATMENT
Give MgSO4:
10g 50% solution (20mls) is injected intramuscularly.
Continue antihypertensive drug
During ConvulsionGOAL OF THERAPY
To treat convulsions and prevent
recurrence
To control the blood pressure.
To stabilise the mother.
To deliver the fetus.
Continue MgSO4 infusion 1g/hour and to be continued till 24
hours after delivery or convulsion whichever is later
If diastolic BP is more than 110mmHg, treat with IV hydralazine
infusion titrate to BP OR
Infusion syringe pump labetalol at 20mg/hr ie. 20mg or
4mls/hr and increase at 30 minutes. Stop infusion if rate
exceeds 150mg/hr (30mls/hr) and inform specialist
After Convulsion

17. Drugs of Choice
Hypertension in Pregnancy

19. Magnesium
Sulphate
MONITORING PARAMETERS
Respiratory rate >6/minute
Urine output >25ml/hr
Patellar reflexes are present -
TOXICITY

20. Hypertension in Pregnancy can be classified into Gestational
Hypertension (GH), Preeclampsia and Eclampsia
In mild to moderate hypertension in pregnancy, the goal of treatment is
to prolong the pregnancy to as near term as possible
In severe pregnancy, the goal of treatment is to prevent cerebrovascular
accident in the mother while trying to achieve a clinically useful
prolongation of pregnancy
1.
2.
3.
SUMMARY of Hypertension
in Pregnancy