Transcript Normal Labor and Delivery

Haemoglobinopathies
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-inherited conditions
- haemoglobin is abnormal.
- a haem unit made up of an iron &protein.
- 97% of adult Hb (HbA) has two α- and two βchains
• -is HbA2 and is composed of two α- and two δchains.
• -Fetal Hb (HbF) has two α- and two γ-chains
• - by 6 months of age this has been replaced by
adult haemoglobin.
• -. Blood is examined by electrophoresi
• Thalassaemia
• -The basic defect is a reduced rate of globin chain
synthesis in adult haemoglobin.
• -ineffective erythropoiesis and increased
haemolysis
• - a low Hb and MCHC level but raised serum iron
level.
• - Definitive diagnosis DNA analysis.
• - The severity of the condition depends on the number of
abnormal genes.
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• Types of thalassaemia and their inheritance
• α-chains
• α-thalassaemia major = four defective α genes
• α-thalassaemia intermedia = three defective α genes
• α-thalassaemia minor = two or one defective α genes
• β-chains
• β-thalassaemia major = two defective β
genes
• β-thalassaemia minor = one defective β
gene
• Alpha thalassaemia major
• α-Thalassaemia major is incompatible with
extrauterine life.
Beta thalassaemia major
• -severe haemoglobin deficiency, which may result
in cardiac failure and death in early childhood.
• - the ineffective erythropoiesis and increased
haemolysis cause hypersplenism.
• -A splenectomy is often performed in order to
increase RBC survival and reduce the need for
frequent blood transfusions.
• - Blood transfusions increase the possibility of
survival to childbearing age.
Alpha and beta thalassaemia
minor
• -α- and β-thalassaemia minor is the most common
problem encountered among pregnant women.
• -This heterozygous condition produces an anaemia
that is similar to iron deficiency in that the Hb, the
MCV and the MCH are all lowered.
• -A definitive diagnosis needs DNA analysis.
• -no deficiency in iron
• -. In pregnancy, oral iron and folate
supplements are necessary in order to
maintain the iron stores.
• -Parenteral iron should never be given
• - Blood transfusions may be required if the
haemoglobin is thought to be inadequate for
the stress of labour and blood loss at birth
• Sickle cell disorders
• -abnormal haemoglobin alpha or beta
chains; the resulting Hb is called HbS.
• - SCA) abnormal genes have been inherited
from both parents,
• - sickle cell trait (HbAS) only one abnormal
gene has been inherited
• Sickle cell anaemia
• -increased fragility and shortened life span
of 17 days
• -chronic haemolytic anaemia and causes
episodes of ischaemia and pain, known as
attacks of pain or sickle cell crises.
• -Sickling crisis may occur whenever oxygen
concentration is low.
precipitating factors that affect
oxygen uptake include
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-sychological stress
- cold climate
- extreme temperature changes
- smoking-induced hypoxia
-strenuous physical exertion and fatigue
-respiratory disease
- infection
- pregnancy.
• -sickle cells easily adhere to the vascular
epithelium causing a reduced blood flow,
vascular obstruction and hypoxia.
• - This results in acute pain, particularly in
the bones, joints and abdominal organs.
• -Painful episodes last for a few hours to a
few days
Effective management of sickle cell
crisis can be achieved by:
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utilization of pain assessment tools to determine severity of the
pain
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administration of effective analgesia within 30 min of admission
to hospital starting with a non-opioid analgesia, e.g. paracetamol
before moving to opioid analgesia for moderate/severe pain
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liaison with the acute pain management team to ensure adequate
and continuing pain relief
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administration of oral and intravenous fluids to correct
dehydration and electrolyte imbalance caused by pyrexia, vomiting or
diarrhea
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pulse oximetry to assess oxygen saturation and the administration
of oxygen therapy if indicated
• antibiotic treatment if infection is suspected
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assessment of haematological indices and liaison with
the haematology department
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keeping warm and promoting rest
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provision of social, psychological and physical
support to alleviate symptoms associated with chronic
pain.
• -Blood transfusion therapy is key to the management of
sickle cell anaemia as it increases the oxygen carrying
capacity of blood by increasing the haemoglobin
concentration and decreasing the percentage of sickle
haemoglobin.
• - However, due to the risk of developing red cell
antibodies and iron overload
• -the indications for the use of blood transfusion
therapy include:
• 1-acute chest syndrome,
• 2- heart failure
• 3- multiorgan failure
• 4-,stroke
• 5- splenic sequestration
• 6- aplastic crisis.
• -New therapies include the use of drugs such as hydroxyurea, which
inhibits the development of sickle cells by increasing fetal
haemoglobin production.
• - Bone marrow and stem cell transplantation can cure SCA
• -Maternal and fetal effects;
• . -antenatal and postnatal attacks of pain
• -infections
• - pulmonary complications
• - anaemia
• -pre-eclampsia
• - and caesarean section.
• - Fetal and neonatal complications include spontaneous abortion, preterm birth, intrauterine growth restriction and perinatal death
Preconception care;
• . All women should be offered haemoglobin
electrophoresis in early pregnancy and for any
with positive results it is important to have their
partner tested.
• counselling regarding prenatal diagnosis should be
offered
• . If both parents are carriers for HbS (i.e.
heterozygous) there is a one in four chance that
the fetus will inherit the more serious condition,
sickle cell anaemia
Antenatal care:
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Antenatal care aims to minimize the maternal and fetal
complications
• -women with SCA will experience sickle crises during
pregnancy which requires hospital admission and treatment
• -Monitoring of pregnancy is performed at frequent
intervals by a multidisciplinary team involving a midwife,
obstetrician, haematologist, specialist nurse and physician,
• - Midwives have an important role in providing
information and education about SCA and how it affects
• pregnancy, particularly in emphasizing the factors that may
precipitate sickle crisis.
• - initial blood tests should include :
• 1-screening for red cell antibodies
• 2- haemoglobin electrophoresis
• 3- serum iron
• 4- total iron-binding capacity
• 5- serum ferritin levels
• 6-liver function tests,
• 7-blood urea nitrogen and serum creatinine.
• - Regular monitoring of the haemoglobin concentration is
required throughout pregnancy; this is usually in the range
of 6–9 g/dL.
• -Fluid intake should be well maintained to prevent
dehydration
• - detect bacterial infections, particularly genitourinary and
respiratory infections, at an early stage.
• - Good nutrition and folic acid supplements
• -The use of prophylactic blood transfusions to improve the
outcome of pregnancy remains controversial.
- a policy of transfusing only when
indicated, for example in :
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symptomatic anaemia,
severe anaemia with a haematocrit <18%,
sickle crisis,
cardiac failure
or prior to caesarean section.
- Fetal assessment includes regular ultrasound
scans to assess fetal growth. biophysical profiles
and uterine Doppler blood flow studies
Intrapartum care:
• . Timing and mode of birth is gauged
according to maternal and fetal health
• induction of labour or caesarean section
should be performed for obstetric reasons.
• Good pain relief
• adequate hydration are essential to reduce
the risk of a sickle crisis
• an epidural is usually recommended.
• Oxygen therapy via a nasal prong or mask is
advised to maintain adequate oxygenation and
improve cardiac function.
• Prophylactic antibiotics may be considered to
prevent infection.
• Prolonged labour should be avoided and active
management or a caesarean section may be
advised
• CTG monitoring is recommended, especially
where there is intrauterine growth restriction.
Postnatal care.
• Women with SCA are at a high risk of developing
thromboembolic disorders
• early ambulation
• wearing anti-embolic stockings should be encouraged.
• To prevent puerperal sepsis, antibiotic cover is continued
throughout the postnatal period.
• Neonatal screening of babies must be undertaken by
obtaining a sample of neonatal capillary or venous blood at
birth.
• Those with positive results should be followed-up by a
haematologist
• -Sickle cell trait is usually asymptomatic.
• -The blood appears normal
• -although the sickle screening test is
positive.
• -The woman may be mildly anaemic in
pregnancy and folate 5 mg daily is
recommended to help erythropoiesis.
Other rare inherited disorders
Glucose-6-phosphate dehydrogenase
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency is
an X-linked, hereditary genetic defect.
• -G6PD is an enzyme necessary for the survival of the red
cell;
• - when it is deficient RBCs are destroyed in the presence
of certain substances.
• -These include fava beans, sulphonamides, vitamin K
analogues, salicylates and camphor (found in products
such as ‘Vicks VapoRub’).
• - To prevent haemolysis these substances should be
avoided
Spherocytosis
• -the red cells are spherical instead of
biconcave
• - easily destroyed.
• -In this disease the abnormal gene is
dominant.
• -Midwives need to be aware that women
with this condition might have had a
splenectomy