5. Hypertensionin Pregnancy
There are four major types of high blood
pressure that may occur during pregnancy:
Pre-eclampsia
Chronic hypertension
Preeclampsia superimposed upon chronic
hypertension
Gestational hypertension (also called
transient hypertension)
6. Hypertensionin Pregnancy
Chronic Hypertension:
Chronic hypertension is defined as a blood
pressure ≥140/90 mmHg diagnosed either:
- Before pregnancy
- Before the 20th week of pregnancy
- Or that persists more than 12 weeks after
delivery.
8. Hypertensionin Pregnancy
Gestational Hypertension:
Women with gestational hypertension have all of
the following:
- Blood pressure ≥140/90 mmHg
- No protein in the urine (proteinuria)
- Are ≥20 weeks pregnant
- No previous history of high blood pressure.
9. Hypertensionin Pregnancy
Gestational Hypertension:
Over time, some pregnant women with gestational
hypertension will develop proteinuria and be
considered preeclamptic, while others will be
diagnosed with chronic hypertension because of
persistently high blood pressure after delivery.
10. Pre-DisposingFactors
Age: <20 years / >35 years
Ethnicity: Indian, Pacific
Obesity
Diet: <2 servings of fruit per week, high fat
Lifestyle: Working in pregnancy, high stress
Booking BP >130/80: Predisposing hypertension
Miscarriage: 1 x lowers risk (immune response)
3 x increases risk (underlying)
11. Pre-DisposingFactors
Partner: Relationship < 3 months, Father
previously involved in pre-eclamptic
pregnancy
Woman born SGA
Family History: Pre-eclampsia, hypertension,
diabetes, PCOS, underlying
thrombophilias
Obstetric History: Previous pre-eclampsia,
donated gamate
Multiple Pregnancy
12. Pathogenesis
NORMAL PREGNANCY:
Fetal trophoblast invade walls of spiral arteries
This disrupts their smooth muscle layer and
converts them into venous-like channels
Remodelling begins about 5-6 weeks and
continues until around 20-22 weeks
This allows blood supply to uterus to increase
from 10-15 mls (pre-pregnancy) to 600-800 mls
per minute to meet placental blood flow
requirements at term
13. Pathogenesis
In pre-eclampsia, this process is
DEFECTIVE
1. fewer of the arteries
undergoing these changes
2. changes may not extend throughout the
myometrium of the spiral arteries
19. Pathophysiology
FetalSignsandSymptoms
SYMPTOMS: Slowed or slowing fetal growth, signs and
symptoms related to abruption and/or preterm labour
Abnormal biophysical profile score
Slowed growth of the baby, based upon customised
growth chart and/or an ultrasound
Decreased amount of amniotic fluid around the baby, noted
on ultrasound
Decreased blood flow through the umbilical cord,
noted on Doppler tests
22. TestsandInvestigations:
CompleteBloodCount
HAEMOGLOBIN [Hb]: 100 – 140 g/L
The iron-containing protein, which transports
oxygen within the red blood cells
In normal pregnancy, there is a natural decrease
in Hb, due to haemodilation
In pre-eclampsia, expected plasma volume
increase is impaired, affecting Hb estimation
If at 28/40 bloods, Hb is not lower than booking
bloods, this could be significant, and therefore
need to be vigilant
23. TestsandInvestigations:
CompleteBloodCount
HAEMOGLOBIN [Hb]:
As the pregnancy progresses, and capillaries
become more damaged, they begin to leak,
causing fluid to shift from the blood vessels to
extravascular spaces
Blood therefore becomes more concentrated,
and a raised Hb may indicate reduced plasma
(haemoconcentration)
Plasma volume normal with mild disease, but
reduced with severe pre-eclampsia
24. TestsandInvestigations:
CompleteBloodCount
HAEMATOCRIT [PCV]: 0.28 – 0.41 (ratio)
The proportion of total blood volume that is
occupied by erythrocytes
High PCV is suggestive of hypovolaemia (low
volume), which therefore may affect placental
perfusion
No exact levels for Hb and PCV define significant
haemoconcentration, serial measurements are
more useful for monitoring the disease course
25. TestsandInvestigations:
CompleteBloodCount
PLATELETS: 150 – 400 109/L
The total number of thrombocytes, which play
an integral role in haemostasis
Platelet levels decrease as they aggregate
following damage to the endothelial cells of the
capillaries
Day-to day variations common so serial
measurements are necessary and more
informative
27. TestsandInvestigations:
RenalFunctionInvestigations
SERUM UREA: 2.0 – 4.0 mmol/L
An organic chemical compound which
essentially is the waste produced when the body
metabolizes protein
A late sign of renal injury as a result of
pre-eclampsia is impairment of glomerular
filtration which causes an increase in serum urea
28. TestsandInvestigations:
RenalFunctionInvestigations
SERUM CREATININE: 0.04 – 0.08 mmol/L
A breakdown product of creatine (muscle waste
material), which is constantly produced and
filtered by the kidneys
Creatinine is removed from the body entirely by
the kidneys
If kidney function is abnormal, creatinine levels
will increase in the blood
29. TestsandInvestigations:
RenalFunctionInvestigations
URATE (URIC ACID): 0.20 – 0.42 mmol/d
End product of protein metabolism
Excreted by renal tubule, in preeclampsia this
function is impaired by damage to kidney and
blood levels rise
High levels associated with poor fetal outcome
Useful diagnostic feature of early preeclampsia
Diet may affect level
30. TestsandInvestigations:
RenalFunctionInvestigations
PROTEIN-CREATININE RATIO: 0 – 30 mg/mmol
Random (spot) urine protein-creatinine ratio
collected during normal daytime activity
Provides an accurate and rapid quantitation of
proteinuria in pregnant women with systemic
arterial hypertension and increased risk of pre-
eclampsia
31. TestsandInvestigations:
RenalFunctionInvestigations
CREATININE CLEARANCE: 120 – 160 ml/min
The volume of plasma completely cleared of
creatinine per unit of time
Assesses the glomerular filtration rate
Gives an indication of renal function
Creatinine clearance may be reduced in pre-
eclampsia as a result of decreased GFR
Assessed via 24 hour specimen
32. TestsandInvestigations:
LiverFunctionInvestigations
ASPARTATETRANSAMINASE [AST]: < 45 U/L
An enzyme, involved in cellular metabolism
that has raised levels in acute liver damage
Also found in high concentrations in heart,
muscle, kidney, pancreas and red blood cells
If any of these areas are damaged the blood
levels of the enzyme will increase
Not specific for liver function
33. TestsandInvestigations:
LiverFunctionInvestigations
ALKALINE PHOSPHATASE [ALP]: 90 - 250 U/L
An enzyme made in the liver, bone, and the
placenta, released into the blood during injury and
during such normal activities as bone growth and
pregnancy
Involved in cell metabolism and present in nearly all
tissues
Levels reach up to 3 times normal in pregnancy due
to placental phosphatase
Exaggerated increases may point to placental and
hepatic damage in preeclampsia
34. TestsandInvestigations:
LiverFunctionInvestigations
ALANINETRANSAMINASE [ALT]: 7 - 45 U/L
An enzyme involved in cellular respiration, found in
highest amounts in the liver. It is released into the
blood through liver injury.
Found in low levels in other tissues
High levels are specific for hepatic damage
In normal pregnancy AST and ALT
usually remain unchanged.
In severe preeclampsia they may be elevated
38. TestsandInvestigations:
LiverFunctionInvestigations
SERUM ALBUMIN: 35 – 45 g/L
Albumin transports many small molecules in the
blood (for example, bilirubin, calcium,
progesterone, and drugs). It is also of prime
importance keeping the fluid from the blood from
leaking out into the tissues.
Because albumin is made by the liver, decreased
serum albumin may result from liver disease
In pre-eclampsia low levels of albumin may also be
the result of protein lost through proteinuria
39. TestsandInvestigations:
Coagulation
ACTIVATED PARTIALTHROMBOPLASTINTIME [APTT]:
35 - 45 secs
When you bleed, the body launches the coagulation
cascade. There are three pathways to this event.
The APTT test looks at special proteins, called
factors, found in two of these pathways (intrinsic).
A blood test that looks at how long it takes for
blood to clot
It can help tell if there are bleeding or clotting
problems
A prolonged APTT time can be indicative of
disorders such as DIC, haemophilia, lupus, etc.
40. TestsandInvestigations:
Coagulation
THROMBIN CLOTTINGTIME: 10-18 secs
A test which measures time required for plasma
fibrinogen to form thrombin. Exogenous
thrombin is added to citrated plasma and the
time to clot formation is measured.
TCT is prolonged with abnormalities of
fibrinogen and in the presence of heparin or of
fibrin/fibrinogen degradation products
Prolonged in DIC as clotting mechanism fails
41. Section88 MaternityNotice
ReferralGuidelines
Current Pregnancy - Pre-Eclampsia:
LEVEL 3 (Code 4022)
- Blood Pressure >140/90 (or rise of >30/15)
AND...
- Proteinuria > 0.3g / 24 hours
- Platelets < 150 x 109 / L
- Abnormal renal or liver function
- Imminent eclampsia / eclampsia
45. CLASPTrial
CollaborativeLow-doseAspirinStudiesinPregnancy
Aspirin and Calcium thought to produce
modest reductions in blood pressure in
pregnant women who are at above-average
risk for PE
Debate continues over gestation at which
prophylactic treatment should begin, but
earlier the better (approx. 6/40 gestation)
Aspirin may also be beneficial in the
treatment of IUGR
46. CLASPTrial
CollaborativeLow-doseAspirinStudiesinPregnancy
For women who are at high risk of pre-
eclampsia (>20%)
Aspirin 100 mg daily
Calcium 1.5 g daily
For women who are at very high risk of pre-
eclampsia or previous pregnancy had very
early onset
Heparin 7500 u BD or enoxaparin 40mg daily
Aspirin 100 mg daily
47. Management
Depends on many factors:
Gestational age of the pregnancy
Severity of the disease
Presence of complicating factors
Evidence of maternal compromise
Evidence of fetal compromise
The definitive treatment for pre-eclampsia is
delivery of the fetus and placenta
48. Management
Expectant Management:
No evidence that hospital admission for mild PE
improves maternal or fetal outcomes
Admission to hospital is stressful, emotionally and
financially costly
Women with mild PE without significant
proteinuria may be treated as outpatient or
admitted as a ‘day case’ for assessment and
evaluation
49. Management
Expectant Management:
Expectant management at home or hospital requires:
Reduced activity
Woman may be advised to stop working
May be advised to go on bed rest – although this is logical
it has not been proved to improve outcomes
Careful recording and daily checking of:
Fetal activity
Blood pressure
Urine protein
Any other signs and symptoms of PE
50. Management
Collaborative Management:
The goal is to:
Recognise pre-eclampsia early
Monitor the woman for evidence of disease
progression that would mandate either delivery
of more intensive fetal surveillance
51. Management
Collaborative Management:
Education for the family begins as soon as the diagnosis is
confirmed:
Should include information about the disease process
Signs and symptoms
Proposed course of treatment
Physical and laboratory investigations
Medications
Potential complications to mother and baby
Plan for birthing
Baseline laboratory evaluations:
Should be performed early in pregnancy for all women known to be
at high risk of PE
52. Management
Collaborative Management:
Blood pressure:
Should be recorded more frequently in women at high risk of
PE
Rapid increases warrant closer observation
Fundal height:
Should be measured at each visit
A measurement less than expected may indicate IUGR or
oligohydramnios
Presence of either IUGR or oligohydramnios may occur
before any other diagnostic criteria for PE become apparent
Oedema:
Rapidly increasing generalised, facial and/or periorbital
oedema requires further assessment
53. Management
Collaborative Management:
Once hypertension is documented in second half of
pregnancy, or onset of PE is suspected laboratory
investigations to track progression:
Full blood count
Liver function tests
Renal tests
Coagulation screening
Urinanalysis
54. Management
Collaborative Management:
Fetal monitoring:
Antepartum surveillance (CTG’s)
Symphyseal-fundal height measurements
Record of fetal movements
Ultrasonography:
Amniotic fluid index
Fetal growth
Biophysical profiles
Umbilical artery Doppler studies
Used to monitor fetal growth and to ascertain the most
appropriate and safest time for delivery
55. Management
Hospital Management:
May be necessary for woman who:
Feel safer in hospital
Hypertension worsens
Presence of significant proteinuria
Signs of end organ involvement
There are concerns about fetal wellbeing
Baseline laboratory evaluations as with Collaborative
management to monitor progression of disease
Crucial that an accurate fluid-balance chart maintained to
ensure that renal impairment detected early
56. Management
AntihypertensiveTherapy:
Indicated once the BP is persistently above
>160/100 mmHg, with the aim of achieving a
diastolic reading of 90 – 100 mmHg
This is to avoid ‘overcorrection’ and the risk of
exacerbating placental hypoperfusion
Drugs used include methyldopa, atenolol and
labetalol
ACE inhibitors contraindicated in pregnancy
57. Management
Timing of Delivery:
Delivery is the only cure for clinically diagnosed PE
Should be accomplished once the fetus is mature
Earlier if maternal condition deteriorates or if there is
evidence of significant fetal compromise
Delivery should always take place in a level 2 hospital,
where there are obstetric and paediatric facilities
readily available
Timing and management of delivery requires close
collaboration between the woman, midwifery,
obstetric, paediatric and anaesthetic teams
58. Management
Timing of Delivery:
If fetus is between 24 -34 weeks gestation and urgent
delivery is required, corticosteroids are administered
to the mother
Vaginal birth preferable
Epidural anaesthesia preferred choice of pain relief as
the maternal stress response releases catecholamines
and increases BP, although contraindicated if there is
evidence of coagulopathy
Continuous monitoring of fetus
Syntometrine to be avoided for third stage due to
ergometrine component
59. Management
Timing of Delivery:
Fetal indications for immediate delivery:
Intrauterine Growth Restriction
Non-reassuring CTG
Oligohydramnios
Maternal indications for immediate delivery:
Progressive deterioration of liver function
Progressive deterioration of renal function
Suspected placental abruption
Persistent severe headache or visual changes
Persistent severe epigastric pain, nausea or vomiting
60. Management
ManagementAfter Delivery:
30% of cases of PE only diagnosed in postpartum
period
Following initial improvement, 60% of women will
worsen within 48 hours of delivery
Antihypertensive drugs usually continued for a
further 48 hours
Close monitoring of BP should continue, as well as a
meticulous fluid balance chart
Good analgesia cover to reduce maternal stress
Follow-up consultation and/or debrief
61. ImplicationsforMidwiferyCare
Must begin with an accurate record of a woman’s
history to identify risk factors and establish
baseline recordings of BP and laboratory values
Early recognition and diagnosis of physical signs
rather than symptoms, as woman may feel well,
yet have severe pre-eclampsia
Scope of care depends on severity of disease
Referral guidelines encompass a three-way
discussion between the woman, her midwife,
and specialist – therefore availability of the
midwife paramount