Sickle cell anemia is an autosome linked recessive trait that can be transmitted from parents to the offspring when
both the partners are carrier for the gene (or heterozygous). The disease is controlled by a single pair of allele, HbA
and HbS. Out of the three possible genotypes only homozygous individuals for HbS (HbS, HbS) show the diseased phenotype. The ability to predict the clinical course of SCD during pregnancy is difficult. It is mandatory to follow up the patient closely from the very beginning i.e. from preconception to antenatal till labor. SCD is associated with both maternal and fetal complications and is associated with an increased incidence of perinatal mortality, premature
labor, fetal growth restriction and acute painful crises during pregnancy.
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Apollo Medicine 2012 September; Vol. 9, No. 3
ANTENATAL CARE
Women with SCD 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. Women
with HbSC experience fewer adverse outcomes, but there
is still evidence of an increased incidence of painful crises
during pregnancy, fetal growth restriction, antepartum
hospital admission and postpartum infection. Although
outcomes among women with HbSC are better than in
women with HbSS, some do have serious, unpredictable
complications, and women with HbSC should therefore
be monitored in the same way as those with HbSS.3
Management & treatment
Women should be offered a viability scan at 7e9 weeks of
gestation and the routine first-trimester scan (11e14 weeks
of gestation) followed by a detailed anomaly scan at 20
weeks of gestation. In addition, women should be offered
serial fetal biometry scans (growth scans) every 4 weeks
from 24 weeks of gestation. Routine prophylactic transfusion is not recommended during pregnancy for women
with SCD. If acute exchange transfusion is required for
the treatment of a sickle complication, it may be appropriate
to continue the transfusion regimen for the remainder of the
pregnancy. Blood should be matched for an extended
phenotype including full rhesus typing (C, D and E) as
well as Kell typing.
The influenza vaccine should be recommended if it has
not been administered in the previous year. Iron supplementation should be given only if there is laboratory evidence
of iron deficiency. Women with SCD should be considered
for low-dose aspirin 75 mg once daily from 12 weeks of
gestation in an effort to reduce the risk of developing preeclampsia. Women with SCD should be advised to receive
prophylactic low-molecular-weight heparin during antenatal hospital admissions.
Non-steroidal anti-inflammatory drugs (NSAIDs) should
be prescribed only between 12 and 28 weeks of gestation
owing to concerns regarding adverse effects on fetal development blood pressure and urinalysis should be performed
at each consultation, and midstream urine for culture performed monthly.4
EMERGENCY MANAGEMENT
Pregnant women presenting with acute painful crisis should
be rapidly assessed by the multidisciplinary team and
appropriate analgesia should be administered. The
Sharma
requirement for fluids and oxygen should be assessed.
Thromboprophylaxis can be given to women admitted to
hospital with acute painful crisis but Pethidine should be
avoided because of the associated risk of seizures.
SCD is associated with other acute complications
including ACS, stroke and acute anemia. After acute
pain, ACS is the most common complication, reported in
7e20% of pregnancies. Top-up blood transfusion may be
required if the hemoglobin is falling, and certainly if the
hemoglobin is less than 6.5 g/dl, but in severe hypoxia,
and if the hemoglobin level is maintained, exchange transfusion will be required.5,6
Acute anemia in women with SCD may be attributable
to erythrovirus infection. Infection with erythrovirus in
SCD causes a red cell maturation arrest and an aplastic
crisis characterized by a reticulocytopenia. Therefore,
a reticulocyte count should be requested in any woman presenting with an acute anemia and, if low, may indicate
infection with erythrovirus. Other investigations will
depend on the clinical scenario but may include blood
cultures, chest X-ray, urine culture and liver function tests.
In case of low levels of hemoglobin and erythrovirus infection blood transfusion may be required. With erythrovirus
infection there is the added risk of vertical transmission to
the fetus, which can result in hydrops fetalis, hence a review
by a fetal medicine specialist is indicated. Women with
SCD can develop anemia owing to bleeding or any other
causes of anemia incidental to the SCD. Rare causes of
anemia in SCD include malaria and, occasionally, splenic
sequestration in women with a mild phenotype.
LABOR CARE
Pregnant women with SCD who have a normally growing
fetus should be offered elective birth through induction of
labor, or by elective caesarean section if indicated, after
38þ0 weeks of gestation. SCD should not in itself be
considered a contraindication to attempting vaginal delivery
or vaginal birth after caesarean section. Blood should be
cross-matched for delivery if there are atypical antibodies
present (since this may delay the availability of blood),
otherwise a ‘group and save’ will suffice. In women who
have hip replacements (because of avascular necrosis) it
is important to discuss suitable positions for delivery. It is
recommended that, like most ‘high-risk’ conditions,
delivery of the baby at 38e40 weeks of gestation will
prevent late pregnancy complications and associated
adverse perinatal events.
Women should be kept warm and given adequate fluid
during labor. Continuous intrapartum electronic fetal heart
rate monitoring is recommended owing to the increased
4. Management of sickle cell disease in pregnancy
risk of fetal distress which may necessitate operative
delivery. There is an increased risk of painful crisis with
protracted labor (more than 12 h), but this is often
secondary to dehydration. In this situation, if the woman
is well hydrated and labor is progressing, the labor should
be carefully supervised; caesarean section should be considered if labor is not progressing well and delivery is not
imminent. The demand for oxygen is increased during the
intrapartum period and the use of pulse oximetry to detect
hypoxia in the mother is appropriate during labor. Arterial
blood gas analysis should be performed and oxygen therapy
instituted if oxygen saturation is 94% or less. The clinician
should have a low threshold to commence broad-spectrum
antibiotics.8,9
Postpartum contraceptive advice should be given to all
of them Prostoge containing contraceptive like progesterone only pills, cerazette injectable contraceptives
(Depo-Provera) levenorgestrel intrauterine system (Mirena
IUS) are safe and effective in SCD. Estrogen-containing
contraceptives should be used as second-line agents. Barrier
methods are as safe and effective in women with SCD as in
the general population.
DISCUSSION
SCD is associated with both maternal and fetal complications and is associated with an increased incidence of perinatal mortality, premature labor, fetal growth restriction and
acute painful crises during pregnancy. Some studies
describe an increase in spontaneous miscarriage, antenatal
hospitalization, maternal mortality, delivery by caesarean
section, infection, thromboembolic events and antepartum
hemorrhage. An increased risk of pre-eclampsia and pregnancy-induced hypertension has been described in other
studies but not in all. In HbSC there are fewer reported
Review Article
183
adverse outcomes, but there is evidence of an increased
incidence of painful crises during pregnancy, fetal growth
restriction, antepartum hospital admission and postpartum
infection.
CONFLICTS OF INTEREST
The author has none to declare.
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