Hypertensive disorders of pregnancy Flashcards
Hypertensive disorders of pregnancy
- Features
- Complications
Features
* Most common complication
* One of three main causes of maternal death
* May resolve after pregnancy or persist in women with other hypertensive issues (such as
essential hypertension)
* Influenced by parity, ethnicity and dietary intake.
Complications
1. Mild HTN – minimal risk
2. Severe HTN – placental abruption, convolutions, proteinuria, edema, cerebral hemorrhage,
hepatic failure, DIC and death.
Definitions
- HTN - Systolic > 140 or diastolic > 90 (measured by 5th Korotkoff sound, and if absent then 4th
sound) on two or more measures at least 4 hours apart. - Proteinuria - >0.3g/L in 24-hour collection or 1 g/L on random sample on two measures with
minimum 6 hours apart. Factor that determines prognosis. - Edema – weight gain of ~2kg per week in areas such as feet, ankles and abdomen
- Gestational hypertension (pregnancy induced-hypertension PIH) – new onset of HTN (without
pre-eclampsia) after 20 weeks of gestation or within 24-hours of birth. - Chronic HTN – present before pregnancy or diagnosed before week <20
- Unclassified – arise in pregnancy on random basis
Pre-eclampsia
- Definition: HTN + proteinuria after 20 weeks of gestation (mostly seen in primigravida women =
first pregnancy) - Types (also use this for diagnosis):
a. Pre-eclampsia without severe features
▪ HTN >140/90 blood pressure
▪ Proteinuria >300 mg/24h (in a 24-hour collection)
a. Non-specific symptoms: asymptomatic, headache, visual disturbances, edema,
epigastric pain
b. Pre-eclampsia with severe features
▪ Severe HTN >160/110 blood pressure
▪ Proteinuria
▪ Elevated liver enzymes
▪ High serum creatinine (renal dysfunction)
▪ Thrombocytopenia
▪ Symptoms: visual disturbances, pulmonary edema, cerebral symptoms (mental
state)
c. HELLP syndrome
▪ Symptoms: rapid clinical deterioration, presence of pre-eclampsia
Pre-eclampsia
Pathomechanism
a. Vasoconstriction (of uteroplacental and kidneys)
i. During normal pregnancy cardiac output increases and TPR decreases which are
important factors for not developing pre-eclampsia.
However, failure of this
highly contributes to pre-eclampsia development and evidence suggests that:
- RAAS components increased during pregnancy due to excess formation
by the liver as result of estrogen stimulation. - Increased platelets AgII receptor inducing their activation
- Endothelial dysfunction (NO and EDRF are impaired)
- Reduced antioxidant activity (which limits lipid peroxidase that harms
endothelium and results in fluid loss)
b. DIC
c. Genetics
Vasoconstriction and possible abnormal placental implantation or development→
placental damage and hypoperfusion → maternal hypertension and release of trophoblasts to circulation
(thromboplastin rich) → DIC → ischemia and damage of kidney, liver and placenta →
aggravated HTN → acute kidney failure , hepatic failure, cardiac failure, pulmonary edema, infracted placenta with growth restrictions.
Pre-eclampsia
Morphology
d. Kidney – swelling, proliferation of endothelial cells, hypertrophy and hyperplasia of
mesangial cells, fibrin deposition (as result of hypertension and fibrin degradation
associated with DIC) in basement membrane
e. Placenta – loss of syncytium, villi necrosis, cytotrophoblast proliferation and trophoblast
membrane thickening → impaired trophoblastic invasion which normally vasodilates spiral arterioles
HELLP syndrome
- Acronyms: Hemolysis, Elevated Liver enzymes, Low Platelets
- Features:
a. Associated with severe pre-eclampsia and is extension of DIC (termination of pregnancy
needed)
Management
Gestational HTN and Pre-eclampsia
Assessment status (fetal and maternal)
and necessity for hospitalization and deliver by:
laboratoy values, fetal
ultrasound, non-stress test (NTS) – 20-40
minutes of CTG recording fetal
movements in relation to heart rate
(different from contraction test that is
used to assess heart rate in relation to
hypoxia).
Depending on results, either
monitor or hospitalize with delivery:
Monitor – 1-2 times a week (blood
pressure, urine analysis and lab tests),
educate patient for identifying symptoms
(mentioned above, reduced fetal
movements, vaginal bleeding) and start
antihypertensive therapy (labetalol,
hydralazine, methyldopa, NO ACE
inhibitors they are teratogenic)
Hospitalize and delivery if: >37 week,
suspected placental abruption,
oligohydramnios, abnormal lab
Management
Severe pre-eclampsia
Delivery is the only treatment.
Delivery if >34 week or <34 week with
maternal or fetal instability.
Immediate delivery if pulmonary
edema, eclampsia, DIC, placental
abruption
Delayed (24h – 48h) delivery if HELLP,
PROM,
Management
HELLP syndrome
Stabilization - blood transfusion and IV
fluids. Antihypertensives - methyldopa, hydralazine, alpha and beta blockers,
nifedipine
Delivery
If before <34 week or at any gestational
age with presence of deteriorating
maternal or fetal status → deliver.
If no maternal of fetal stress and
stabilization has calmed give
corticosteroids for 24-48 hours and
then deliver
Diagnosis
a. 4-hour monitoring until blood pressure has returned to normal.
b. Urine checks for proteinuria
c. Blood count (particular platelets)
d. Renal and liver functions
e. Uric acid
f. Clotting
g. Catecholamines (to rule out pheochromocytoma)
h. Serial ultrasounds (measure fetal growth
every 2 weeks and CSF volume twice a week)
i. Doppler ultrasound – umbilical and uterine arteries (check absence or reverse of flow)
j. Cardiotocography – fetal heart rate and uterine contraction
k. Ultrasound – fetal growth in relation to gestational age, placental implantation and
amniotic fluid
Prevention hypertensive disorders
a. Ca2+ (may reduce risk)
b. Low-dose aspirin (COX inhibitor)
Eclampsia
- Definitions
- Features
- Definition: pre-eclampsia and convulsions (fast relaxing and contracting muscles→seizures). It is
secondary to pre-eclampsia - Features
a. Manifests when pre-eclampsia is not recognized
b. Can be prevented
c. Can occur in pre-, intra- and post-partum periods.
Eclampsia
Management
Management:
d. Pre-term
i. Control seizures
* Ensure airway
* MgSu (drug of choice) - 4g solution over 20 minutes + maintenance dose
1 g/h.
ii. Control blood pressure
- Labetalol 20mg followed by 40mg, 80mg to total of 200mg
- Epidural analgesia - to relief pain and cause vasodilation in lower
extremities.
iii. Fetus delivery – after controlling blood pressure, oxytocin induced labor or Csection are followed.
b. Post-term – continues up to 7 days after delivery. In case seizures continue, epilepsy or
cortical thrombus need to be considered.
i. Constant patient observation
ii. Maintain levels of sedation
iii. Antihypertensive therapy (until returned to normal)
iv. Fluid balance
