SICKLE CELL ANAEMIA IN PREGNANCY FOR MBBS UNDERGRADUATES OBG

1. SICKLE CELL
ANAEMIA
- ANJANA.B.S

2. DEFINITION
Sickle haemoglobin (HbS) results from substitution of glutamic acid with valine at the sixth
position in the Beta globin chain of haemoglobin - point mutation in chromosome 11.
3 types of sickle cell disease:
 Homozygous HbS individuals with no HbA have full blown sickle cell anemia
 Compound heterozygous states (Hb S & Other abnormal haemoglobin) like sickle cell haemoglobin
C disease ( HbS & Hb C) & Sickle cell alpha thalassemia disease.
 Sickle cell trait (heterozygous) 40% HbS and 60% HbA
PATHOGENESIS
Under conditions of hypoxia, cold, acidosis and dehydration, sickling of red cells occurs i.e. these
red cells become sickle shaped and haemolyse easily resulting in anaemia & jaundice. These cells
are rigid and fail to pass through the microcirculation causing intravascular thrombosis.

3.  Intravascular sickling leads to vaso oclusive symptoms and tissue infarction along with severe pain called
sickling crisis. This can occur in any organ & cause renal damage, splenomegaly, hepatomegaly, pulmonary
infarction, cerebrovascular accidents and leg ulcers.
 Common complication is acute chest syndrome characterised by pleuritic chest pain, fever, cough and hypoxia.
Pathology may include infection, infarction & fat embolization . Recurrent episodes can lead to pulmonary
hypertension. Avascular necrosis most commonly involving the head of the femur.
 Pregnant women can also have cardiac dysfunction due to ventricular hypertrophy. These changes in placenta
can cause preeclampsia and harmful effects on fetus.
Many of these patients have chronic haemolytic anaemia but are generally healthy except during crisis

4. LAB FINDINGS IN SICKLE CELL ANAEMIA
Peripheral blood
 Hb: decreased & usually in the range of 5-10g/dl
 PCV: decreased & usually in the range of 18-30%
 Reticulocytosis: increased reticulocyte count and usually in range of 5-20%.
 ESR: Low because sickle cells do not form rouleaux.
Peripheral smear
 RBCs
 Red blood cells are normocytic normochromic to mildly hypochromic
 Moderate to severe anisopoikilocytosis.
 The characteristic cell seen in the smear is the sickle cell. These appear as long , curved cells with pointed ends.
 Smear may also show target cells( due to red cell dehydration) and ovalocytes.
 There is polychromatophilia due to reticulocytosis.
 Few RBCs show Howell Jolly bodies ( small nuclear remnants), which is due to hypofunction of spleen resulting
from autosplenectomy.
 Few nucleated RBCs are also observed.
 WBCs: Total count mildly increased
 Platelets: Platelet count is mildly increased.

5. Bone Marrow
 Cellularity: Bone Marrow hypercellular
 Erythropoiesis: bone marrow - normoblastic erythroid hyperplasia but chronic
haemolysis can result in secondary folate deficiency and it shows megaloblastic
type of hyperplasia. BM hyperplasia expands the marrow causing resorption of
bone and secondary new bone formation. In severe cases, these changes result
in prominent cheek bones and skull bones resemble a crew cut (hair on end
appearance) in X-ray.
 Myelopoiesis Within normal limits
 Megakaryopoiesis: Within normal limits
 Iron stores: usually increased
Serum findings
 Iron status: Increase in serum iron , serum ferritin and transferrin saturation.
 Serum bilirubin: increased haemolysis can cause hyperbilirubinemia and
consequently pigment gallstones.
Urine urobilinogen: It is increased.

6. Diagnosis
Screening recommended for a high risk population. The diagnosis can be made on
haemoglobin electrophoresis. Electrophoresis will also reveal the relative
proportions of HbS and HbF. The more the proportion of HbF, the better is the
outcome.

7. Complications
Both the maternal and perinatal mortality and morbidity are increased.
Maternal
• Acute painful sickling crisis (common in pregnancy)
• Early onset preeclampsia and HELLP syndrome
• Infections like pyelonephritis and puerperal sepsis
• Thromboembolism
• Cardiac dysfunction
Perinatal
• Miscarriage and preterm delivery
• Fetal growth restriction
• Intrauterine fetal death
• Isoimmunisation and haemolytic disease of newborn

8. MANAGEMENT
Preconceptional
Pregnancy should be planned and chronic disease should be assessed
preconceptionally for end organ damage.
Women with hypertension, proteinuria & proliferative retinopathy should be
identified.
Renal and liver function should be checked.
An echocardiography should be done to assess the presence of pulmonary
hypertension and cardiac dysfunction.
Those who have had multiple blood transfusions should be screened for iron
overload and aggressive iron chelation done before pregnancy. Such women should
be screened for red cell antibodies as it may predict an increased risk of haemolytic
disease of newborn. Their vaccination status should also be checked. They should
receive hepatitis B vaccination if not already immunised.

9. Other vaccines to be considered are influenza, swine flu, meningococcal and pneumococcal
vaccines.
Folic acid 5 mg daily is supplemented preconceptionally and continued throughout pregnancy
because of the increased turnover of red cells.
Hydroxyurea should be stopped at least 3 months preconceptionally.
Women with hypertension and renal disease, who are on ACE inhibitors and ARB’S, should be
switched to other drugs preconceptionally.
 Partner screening should be encouraged prior to pregnancy and genetic counselling given in
high risk cases.
 Prenatal diagnosis is available by DNA analysis of material obtained by chorionic villus
sampling or amniocentesis.
Preimplantation genetic diagnosis of SCD is now available but it requires assisted reproductive
technology.

10. Prenatal Care
Prenatal care should be provided jointly by an obstetrician and a haematologist.
 If end organ damage screening has not been done preconceptionally, it should
be done.
Women should aim to avoid precipitating factors of sickle cell crises such as
exposure to extreme temperatures, dehydration and overexertion. Persistent
vomiting can lead to dehydration and sickle cell crisis and women should be
advised to seek medical advice early.
 The influenza vaccine should be recommended if it has not been administered .
 Folic acid 5 mg daily and prophylactic antibiotics can be given.

11. Oral iron should be given only if there is laboratory evidence of iron deficiency.
Women with SCD should be considered for aspirin 150mg once daily after 12 weeks of
gestation in an effort to reduce the risk of developing preeclampsia and fetal growth
restriction.
Blood pressure and urinalysis should be performed at each consultation, and midstream urine
for culture performed monthly to screen for asymptomatic bacteriuria. If detected, it should
be treated promptly to prevent pyelonephritis .
Routine prophylactic blood transfusion is not recommended in pregnancy.
If partner screening was not done previously, it should be done and prenatal diagnosis offered
if necessary.
 Apart from the routine scans, these women should be offered monthly growth scans to check
for growth restriction.

12. Complications
Complications in pregnancy are acute painful sickling crisis, acute stroke and severe anaemia.
 Acute painful sickling crisis is the most common complication of SCD in pregnancy & should
be managed aggressively with analgesics, hydration and antibiotics.
A probable danger is that it may difficult to differentiate crisis from other obstetric conditions
causing severe pain, like abruption.
Thromboprophylaxis with heparin should be considered in acute painful crisis.
 In the case of severe anaemia, blood transfusions may be needed, which will replace the
abnormal cells with normal red cells for the time being. Sometimes exchange transfusion may
be indicated.

13. Intrapartum Management
Elective delivery is preferable after 38 weeks of gestation.
If fetal growth restriction is present , earlier delivery may be indicated.
Vaginal delivery is preferred.
If caesarean section is indicated general anaesthesia is best avoided and epidural anaesthesia
preferred.
Blood should be kept ready and in case of atypical antibodies, blood should be crossmatched
for delivery.
 The woman should be kept warm and adequate hydration and oxygenation should be
maintained carefully.
Postpartum Management
Heparin is given prophylactically to prevent thrombosis.
 Infections should be monitored carefully and vigorously treated in the puerperium.
If the baby is at high risk for SCD, it should be tested for.
Haemolytic disease shoud be anticipated in cases where red cell antibodies are identified in
the mother.

14. Contraception
The combined estrogen- progesterone pill should be avoided for contraception.
Progesterone is known to prevent sickle cell crisis and hence, progesterone only contraception
is ideal. Intrauterine devices are not preferred due to the risk of infection.
Sickle Cell trait
This is the heterozygous condition, where one gene is of HbA.
The only complication in pregnancy is an increased incidence of asymptomatic bacteriuria and
urinary tract infection.
It is not associated with fetal loss.
 Inheritance is a concern when the partner is also a carrier and hence partner screening is
essential.

15. Thank you!!