Sickle Cell Disease in Pregnancy, Management of Flashcards
what is SCD?
group of inherited single-gene autosomal recessive disorders caused by the ‘sickle’ gene, which affects
haemoglobin structure
SCD prevalent area?
- origins in sub-Saharan Africa and the Middle East,
- most prevalent in African descent, Caribbean, Middle East, parts of India and Mediterranean, and South and Central America.
- migration, SCD: worldwide and Europe & USA.
The term SCD includes
- sickle cell anaemia (HbSS)
heterozygous haemoglobin S + other abnormal Hb.
- Hb S+ Hb C (giving HbSC),
- Hb S+ Hb beta thalassaemia (HbSB thalassaemia)
- Hb S+ Hb D, E or O-Arab.
- All these genotypes: similar clinical phenotype of varying severity.
- Hb S + normal Hb (A), known as sickle trait (AS), is asymptomatic, except for possible increased risk of UTI & microscopic haematuria,.
SCD burden
- most common inherited condition worldwide
- 300 000 children with SCD are born each
year - 2/3 of these births are in Africa.
- In UK, 12 000–15 000 affected individuals and
- over 300 infants born with SCD in the UK each year who are diagnosed as part of the neonatal
screening programme. - approximately 100–200 pregnancies with SCD per year in UK.
Complications: of SCD
- haemolytic anaemia,
- vaso-occlusion small blood vessels,
- acute painful crises.
- stroke,
- retinal disease,
- pulmonary hypertension,
- cholelithiasis
- renal dysfunction,
- avascular necrosis (which commonly affects the femoral head and may necessitate hip replacement).
- leg ulcers,
What are the additional risks to the woman and baby?
1- increase in spontaneous miscarriage,
2- fetal growth restriction
3- premature labour,
4- perinatal mortality,
5- acute painful crises during pregnancy.
6- antenatal /antepartum hospital admission
7- Infection, 8- antepartum haemorrhage. 9- pre-eclampsia and 10- pregnancy-induced hypertension + _ 11- thromboembolic events
12- delivery by caesarean section,
13- postpartum infection
14- maternal mortality,
Information that is particularly relevant for women planning to conceive includes:
● the role of dehydration, cold, hypoxia, overexertion and stress in the frequency of sickle cell crises
● how nausea and vomiting in pregnancy can result in dehydration and the precipitation of crises
● the risk of worsening anaemia, the increased risk of crises and acute chest syndrome (ACS) and risk of increased infection (especially urinary tract infection) during pregnancy
● the increased risk of having a growth-restricted baby, which increases the likelihood of fetal distress, induction of labour and CS
● the chance of their baby being affected by SCD
● an up-to-date assessment for chronic disease complications.
The assessment for chronic disease complications should include:
● Screening for pulmonary HTN with echocardiography. - incidence of pulmonary HTN increased with SCD and increased mortality.
- tricuspid regurgitant jet velocity > 2.5 m/second high risk of pulmonary HTN. Screening if not been last year.
● BP and urinalysis: to identify HTN and/or proteinuria.
- Renal and LFT annually to identify sickle nephropathy and/or deranged hepatic function.
● Retinal screening. Proliferative retinopathy is common with SCD, especially with HbSC, and can loss of vision.
- no randomised evidence: routine screening or only if visual symptoms, but screened preconceptually.
● Screening for iron overload. multiply transfused in past or high ferritin level, T2* cardiac MRI may helpful to assess body iron loading.
- Aggressive iron chelation before conception is advisable significantly iron loaded.
● Screening for red cell antibodies. increased risk of haemolytic disease of the newborn.
What is the importance of genetic screening and what procedure(s) are involved?
- haemoglobinopathy status of their partner
determined before pregnancy. - If identified as an ‘at risk couple’, as per National
Screening Committee guidance, they should receive counselling and advice about reproductive options.
Carrier state in partner which requires referral for counselling and offer of prenatal diagnosis
- woman SCD
HbS
β thalassaemia
HbC
D-Punjab
O-Arab
Carrier state in partner which requires counselling and may need further investigation
- woman SCD
HbE
DB thalassaemia
Lepore
Hereditary persistence of fetal hemoglobin (HPFH)
What is the importance of antibiotic prophylaxis and immunisation?
Penicillin prophylaxis or equivalent should be prescribed.
Vaccination status should be determined and updated before pregnancy.
What vitamin supplements should be given?
Folic acid (5 mg) should be given once daily both preconceptually and throughout pregnancy.
What medications should be reviewed preconceptually?
- Hydroxycarbamide (hydroxyurea) should be stopped at least 3 months before conception.
- ACE inhibitors & angiotensin receptor blockers should be stopped before conception.
SCD: Antenatal care: General aspects
- provided by MDT including obstetrician & midwife with experience of high-risk antenatal care & haematologist with an interest in SCD.
- medical review by haematologist and be screened for end organ damage (if not been preconceptually).
- 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 & women should be advised to seek medical advice early.
- influenza vaccine should be recommended if not been administered in previous year.
