Overview
2 separate Blood Pressure (BP) readings >140/90 mmHg at least 4 hours apart are needed to diagnose hypertension. All pregnant patients with hypertension should get a urinalysis to look for proteinuria.
| No or trace proteinuria (<300 mg/dL) | Proteinuria (≥ 300 mg/dL or ++ dipstick) | |
|---|---|---|
| < 20 weeks gestation | Chronic hypertension | Chronic hypertension with superimposed pre-eclampsia |
| ≥ 20 weeks gestation | Gestational hypertension | Pre-eclampsia |
| Pre-eclampsia with severe features | ||
| Eclampsia | ||
| HELLP syndrome |
- Indications for induction of labour or delivery in pregnant patients with hypertension
- Abnormal fetal testing
- Intrauterine growth restriction
- Development of pre-eclampsia or eclampsia
- Evidence of end-organ damage
- Labour or rupture of membranes
- Patient education and prevention of pre-eclampsia
- Educate the patient on the risk of recurrence
- Regular screening of blood pressure and urine, especially after 20 weeks
- Junior dose aspirin prior to and during subsequent pregnancies to reduce the risk of developing pre-eclampsia. Ideally from 13 weeks (or before the start of the second wave of placentation at 16 weeks) to 34 weeks gestation
- Doppler ultrasound of the umbilical artery to identify high-risk mothers
Blood Pressure in Pregnancy
Although pregnancy is a high-volume state, systemic vascular resistance decreases giving an overall reduction in BP (CO increases by 30-50%, but SVR decreases by 20%). BP reaches a nadir in the mid-second trimester and gradually increases to baseline in the third trimester.
NB:
BPs should never be higher than pre-pregnancy baseline
Hypertensive disorders in pregnancy are the leading cause of preterm delivery
Gestational Hypertension
Gestational hypertension is a sustained elevation of BP (>140/90 mmHg) after 20 weeks gestation in the absence of proteinuria in a normally normotensive patient. The next best step after getting a high BP reading is to repeat the BP measurement after 4 hours. For treatment, our BP goal should be between 130-140 systolic and 90-100 diastolic. Fetal demise can occur at BP < 120/60 mmHg. Blood pressure usually returns to normal at 12 weeks post-partum (3 months post-partum) in patients with gestational hypertension.
- Risk factors for grestational hypertension
- Primigravida (RR 1.5 – 8)
- Hypertension in a previous pregnancy
- Age > 40 yo
- BMI ≥ 35
- Multiple pregnancies
- Family history of gestational hypertension
- Medical conditions (autoimmune disorders, chronic kidney disease, diabetes mellitus)
- Investigations
- Urinalysis: Normal
- CBC with PBF: normal
- U/E/Cs: normal
- LFTs: Normal
- PT/PTT: Normal
- Obstetric ultrasound: to estimate fetal weight, amniotic fluid index, and Resistive index
- Treatment of Gestational Hypertension
- Lifestyle modifications
- PO Methyldopa or Labetalol or Nifedipine *or *Hydralazine
- Treatment of Severe gestational Hypertension (BP >160/110 mmHg)
- IV Labetalol or IV Hydralazine or PO Nifedipine
- Magnesium sulfate for seizure prophylaxis
Delivery plan for gestational hypertension
| Gestational age | Delivery plan |
|---|---|
| < 37 weeks and stable | Expectant management. Dexamethasone if < 34 weeks |
| < 37 weeks and unstable (or indications mentioned above present) | Induction. Dexamethasone if < 34 weeks |
| ≥ 37 weeks | Induction |
- Complications of gestational hypertension
- Preterm delivery
- Intrauterine growth restriction
- Small for gestational age
- Development of pre-eclampsia
- Abruptio placentae
- Fetal demise
- Maternal malignant hypertension (cerebral haemorrhage, cardiac decompensation, and renal failure)
- Warning symptoms for the development of pre-eclampsia
- Development of 1+ or greater proteinuria
- Vision changes (blurred vision)
- Headaches
- Right upper quadrant pain pain
- Peripheral edema
- How would you distinguish gestational hypertension from chronic hypertension?
- Chronic hypertension is hypertension before pregnancy or before 20 weeks of gestation
- How would you distinguish gestational hypertension from pre-eclampsia?
- Pre-eclampsia has a dipstick urine protein + or > 300mg/24hrs with hypertension
Pre-eclampsia
Pre-eclampsia is a disorder of widespread vascular endothelial malfunction and vasospasm, clinically defined by hypertension (BP > 140/90 mmHg) and proteinuria (+ dipstick or >300 mg/day) occurring between 20 weeks gestation and 4-6 weeks postpartum. It has no definitive etiology, but is probably alloimmunogenic.
Uric acid > 5.5 mg/dL can be used as an alternative to indicate the presence of pre-eclampsia in a patient with chronic hypertension
The key principles of managing patients with pre-eclampsia includes :
- Prevent development of pre-eclampsia with junior aspirin
- Prevention of seizures with magnesium sulphate
- Blood pressure control
- Evaluate for end-organ damage (including hepatic and renal dysfunction)
- Optimizing delivery timing
- Close monitoring of the mother and fetus (including post-partum).
The definitive management of pre-eclampsia is delivery (termination of the pregnancy). It is important to balance fetal well-being (close monitoring and non-stress testing) as well as maternal well-being. Severe pre-eclampsia should be managed actively. There is no room for conservative management of severe pre-eclampsia.
Pre-eclampsia develops in 5-6% of live births usually towards the end of the 3rd trimester.
Definition of terms
| Term | Definition |
|---|---|
| Pre-eclampsia | SBP > 140 or DBP > 90 mmHg AND Proteinuria: 1+ dipstick or 300mg/day |
| Pre-eclampsia with severe features | Satisfies criteria of pre-eclampsia AND at least one severe feature |
| Chronic hypertension with superimposed pre-eclampsia | SBP >140 or DBP > 90 mmHg before 20 weeks gestation AND proteinuria 1+ dipstick or 300 m/day after 20 weeks gestation. Can also have chronic hypertension with super-imposed severe pre-eclampsia; the criteria are the same. |
- Features of severe pre-eclampsia
- Refractory headacheVisual changesSBP > 160 mmHgDBP > 110 mmHGPulmonary edemaAcute renal failureRUQ or epigastric painHELLP
- Hemolytic anemiaElevated Liver Enzymes 2x upper limit of normal(AST or ALT)Low platelets (< 100k – moderate thrombocytopenia)
- Refractory headacheVisual changesSBP > 160 mmHgDBP > 110 mmHGPulmonary edemaAcute renal failureRUQ or epigastric painHELLP
- Risk factors for pre-eclampsia
- Nulliparity with the particular father
- Extremes of age (mean age at 19 years old)
- Multiple gestation
- Chronic hypertension
- Diabetes
- Renal disease
- Father’s mother has a history of pre-eclampsia
- Parental ethnic discordance
- Pathophysiology of pre-eclampsia
- Waves of placentation
- First wave (6-10 weeks) involves invasion of the trophoblast into the decidua and remodelling of the spiral arteries
- Second wave (14 – 16 weeks) involves deeper invasion of the trophoblasts into myometrial segments of the spiral arteries
- Stage 1: Abnormal trophoblast invasion
- Failure to transform spiral arteries into lo-capaticance vessels due to patchy trophoblast invasion (possibly due to abnormal adaptation of the maternal immune system)
- Spiral arteries retain their muscular walls preventing the formation of high-flow, low-impedance uteroplacental circuation
- This leads to uteroplacental ischemia
- Stage 2: Uteroplacental ischemia
- Uteroplacental ischemia results in oxidative and inflammaotory stress
- Secondary mediators e.g. endotheloin cause systemic endothelial dysfunction, vasospasm and activation of the coagulation system
- Cardiovascular effects
- Marked peripheral vasocontriction resulting in hypertension
- Increased vascular permeability due to intravascular high pressure and loss of endothelial cell integrity leading to vasogenic oedema
- Renal effects
- Glomeruloendotheliasis = impaired glomerular filtration and proteinuria
- This leads to reduced plasma oncotic pressure and exacerbates oedema
- Hematologic efects
- Widespread endothelial damage causes platelets to adhere and fibrin to be deposited → coagulopathy, hemolysis, and thrombocytopaenia
- Effects on the liver
- Subendothelial fibrin deposition → ischemia and elevated liver enzymes
- Interstitial oedema → stretching of glisson’s capsule → RUQ/Epigastric pain
- Blood vessels may rupture leading to a subscapsular hematoma
- Neurologicla effects
- Vasospasma and cerebral odema → convulsions
- Retinal haemorrhage, exudates and papilloedema → visual disturbances
- Waves of placentation
- Investigations
- CBC: for hemolysis and for Disseminated Intravascular Coagulopathy
- Thrombocytopenia (severe < 50k and moderate < 100k)
- Normocytic anemia
- PBF: For hemolysis
- Schistocytes
- LFTs: Hepatic disorder and HELLP
- Elevated liver enzymes 2x upper limit of normal
- U/E/Cs: for renal dysfunction
- Disturbed BUN/Cr
- Uric acid: for renal dysfunction
- Elevated
- PT/PTT: for for Disseminated Intravascular Coagulopathy
- Elevated
- Fibrinogen: for Disseminated Intravascular Coagulopathy
- Decreased
- CBC: for hemolysis and for Disseminated Intravascular Coagulopathy
- Investigations for fetal wellbeing
- CTG if > 24 weeks
- Biophysical profile
- Umbilical artery flow (for resistive index)
- Follow up to scan to assess fetal growth velocity
Delivery plan for pre-eclampsia
| Gestational age | Delivery |
|---|---|
| 24 – 32 weeks and stable | Expectant management, control blood pressure, corticosteroids and schedule delivery at 34 weeks |
| < 37 weeks and stable | Expectant management, control blood pressure, corticosteroids, and schedule delivery at 37 weeks |
| ≥ 34 weeks and severe features | Control BP, magnesium sulphate, induce labour |
| ≥ 37 weeks and severe features | Control blood pressure, magnesium sulphate, induce labour, and attempt vaginal delivery if there are no contraindications |
- Postpartum management of pre-eclampsia
- Continue magnesium sulfate for 12-24 hours postpartum (25% of seizures occur postpartum)
- Monitor blood pressure (may use Labetalol, Hydralazine, or Nifedipine to control BP)
- Repeat CBC, BUN, Creatinine, and LFTs qd for 3 days
- What should be given if delivering before 34 weeks?
- Betamethasone/Dexamethasone
- When should C-section delivery be considered in pre-eclampsia?
- Preterm birth (< 32 weeks)
- Biophysical profie (≤ 4)
- Maternal complications of pre-eclampsia
- Seizure (eclampsia)
- Cereberal hemorrhage (stroke – most common cause of death)
- Disseminated intravascular coagulopathy and thrombocytopaenia
- Renal failure
- Hepatic failure or rupture
- Pulmonary oedema
- Obstetric and Fetal complications of pre-eclampsia
- Uteroplacental insufficiency/infarction
- IUGR/SGA
- Abruptio placentae
- Intrapartum fetal distress
- Oligohydramnios
- Fetal compromise
Eclampsia
Eclampsia is defined as new onset of seizures or coma in a woman with pre-eclampsia. ****It may occur with or without proteinuria.
Eclampsia occurs in 10 – 20% of cases of severe eclampsia (0.5 % of all pregnacies). 75% of women with eclampsia will have had severe pre-eclampsia. 25% occur before labor. 50% occur during labor. 25% occur postpartum. Maternal mortality is nearly 2%. Fetal mortality is 1 in 14.
- Signs and symptoms of imminent pre-eclampsia (Magpie trial)
- Frontal Headache (83%)
- Hyperactive reflexes (80%)
- Marked proteinuria (52%)
- Generalized edema (49%)
- Visual disturbances (44%)
- RUQ or epigastric pain (19%)
- Altered sensorium
- Signs suggestive of eclampsia in the Fetus
- Intrauterine growth restriction
- Oligohydramnios
- Abnormal fetal oxygenation
- Treatment of eclamptic seizure
- ABCs
- Take the mother to a dark room
- Insert a mouth gag and suction oral secretions
- 100% Oxygen via face mask
- 2 large bore peripheral IVs
- Seizure control
- Magnesium sulphate (first-line)
- Benzodiazepines (diazepam) or phenytoin (if poor response)
- Control severe Hypertension with target BP of <160/110 (About 140 – 150 systolic and 90 – 100 diastolic)
- IV labetalol (first-line) or hydralazine
- Be judicial. Rapid drop in BP an cause inadequate uteroplacental perfusion and fetal compromise
- Start continuous fetal monitoring
- Delivery only after the patient is stabilized
- Betamethasone/Dexamethasone if < 34 weeks
- Nil Per Oral
- Notify anesthesia
- Caesarean delivery
- ABCs
- Post-partum management
- Continue Magnesium sulfate through first 12-24 hours
- Manage post-partum seizures with Magnesium sulfate
HELPP syndrome
Hemolysis Elevated Liver enzymes Low Platelets (HELLP) is a laboratory diagnosis. Should be suspected in any pregnant woman presenting in the second half of gestation or immediately postpartum with significant new-onset epigastric/RUQ pain until proven otherwise
15-20% of women with HELLP syndrome do not have pre-eclampsia but 10-20% of women with severe pre-eclampsia develop HELLP syndrome (compared to about 0.1-0.8% in the general population). Maternal mortality is about 1.1%; infant morbidity and mortality is 10-60%.
- Risk factors (compared to pre-eclampsia)
- Older maternal age (Mean age of 25 yo vs 19 yo in pre-eclampsia)
- White race/ European descent
- Previous pregnancy with HELLP (2-27%)
- Signs and symptoms
- Nausea, Vomiting, Epigastric/RUQ pain (40-90%)
- Headache (33-61%)
- Hypertension (33-88%)
- Visual changes (<20%)
- Brisk tendon reflexes
- Jaundice (5%)
- Investigations
- Complete blood count: Normocytic anemia, Thrombocytopenia
- Peripheral blood film: Schistocytes
- U/E/Cs: Elevated BUN/Cr
- Liver function tests: Elevated AST, ALT (2x ULN), elevated total bilirubin (hemolytic anemia)
- PT/PTT: Normal but proonged in advanced cases
- Serum amylase and Lipase: Normal
- Haptoglobin: low (indicates hemolysis)
- Lactate Dehydrogenase: elevated (indicates hemolysis)
- Fibrinogen: low
- D-dimer: high
- Differentials
- Acute fatty liver of pregnancy: presents with hypoglycemia
- Thrombotic thrombocytopenic purpura: presents with profound thrombocytopenia
- Treatment
- Admit
- Stabilize the patient: IV access and foley for urine output.
- Assess fetal wellbeing: kick-chart, ultrasound and biophysical profile, intermittent auscultation of fetal heart rate etc.)
- BP management: Labetalol or Nifedipine or Hydralazine
- Seizure prophylaxis: Magnesium sulfate
- Serial Liver function test and platelet counts
- Dexamethasone (also matures fetal lungs)
- Periodic recheck CBC and LFTs. If LFTs are worsening get Abdominal CT to evaluate for subcapsular hematoma
- Notify anesthesia
- Delivery
- Deliver immediately if unstable
- <34 weeks and stable: Dexamethasone and evaluate for delivery afer 24-48 hours
- ≥ 34 weeks and stable: Dexamethasone and deliver after 24-48 hours
- Complications of HELLP
- Disseminated intravascular coagulation (21%; dropping platelet count, PT and PTT progressively prolonging)
- Abruptio placentae (6%; vaginal bleeding, abdominal pain, and nonreassuring fetal status)
- Pulmonary edema/ARDS (6%, SOB, CP, or DIB)
- Acute Kidney Injury (2-8%; oliguria, rising creatining levels)
- Subcapsular hematoma of the liver (1%, presents with worsening liver markers)
- Hepatic rupture (rare; sudden worsening of RUQ pain)