Sickle cell anemia is a rare blood disorder passed down in families. Doctors can test for the trait that causes it before, during, or soon after birth.
Sickle cell anemia (SCA) is an inherited blood disorder. This means that it is passed in the genes at conception.
For a baby to be born with the disorder, both biological parents must carry the affected gene (also called the sickle cell trait). A blood test before or during pregnancy can help determine your carrier status and level of risk.
Here’s more about the tests for SCA, how they’re performed, and what the results mean.
If you or your partner have a family history of SCA, you may opt to get genetic testing to determine your carrier status. Genetic testing involves a blood test to look for the sickle cell trait in the genes.
Why is screening necessary? SCA is passed down in an autosomal recessive manner. This means that for a baby to have the disorder, they must inherit a gene from each parent.
It is possible to carry the trait without knowing because carriers do not have symptoms associated with SCA. If both parents are carriers of the gene, there is an increased risk of having a child with the disorder.
This type of testing is called carrier screening. It can be performed before pregnancy (preconception) or during pregnancy (prenatal) — as early as
A negative result means the sickle cell trait was not found in your blood. A positive result means the sickle cell trait was found in your blood.
If your screening is positive, your doctor will test your partner to see if they also carry the trait.
When both parents carry the sickle cell trait, there’s a:
- 1 in 4 chance of the baby not being affected
- 2 in 4 chance of the baby being a carrier of SCA
- 1 in 4 chance of the baby having SCA
If just one parent tests positive for the sickle cell trait, there is a 1 in 2 chance the baby will be an asymptomatic carrier of the disorder.
Carrier screening can be performed with a blood test. During the test, a needle is inserted into a vein in the arm to collect a blood sample. The blood specimen is then sent to a lab for analysis. The results from the carrier screening may take around a week to arrive.
Again, this test can and should be done as early as 8 to 10 weeks into pregnancy. If your result is positive, you may opt for further testing, which must be completed soon after this window of time.
Your doctor can get confirmation about your baby’s SCA status by directly testing fetal or pregnancy cells. This more invasive prenatal testing includes:
Chorionic villus sampling (CVS): The American College of Obstetricians and Gynecologists (ACOG) reports that CVS is usually performed between week 10 and week 13 of pregnancy. It takes approximately 10 minutes to complete, but the appointment may last longer. A sample of cells is removed from the placenta using transabdominal CVS (needle through the stomach) or transcervical CVS (tube inserted through the cervix). You may feel cramping during or in the hours following the procedure.
Amniocentesis: Amniocentesis is usually performed between week 15 and week 20 of pregnancy, per the NHS. It takes approximately 10 minutes to complete, but the appointment may last longer. In this test, your doctor uses a long, thin needle to collect amniotic fluid from the sac that surrounds your baby in the womb. The needle is guided through the abdominal wall using ultrasound imaging. You may experience cramping or pressure during the procedure.
There is no standard cure for SCA. Babies born with the disorder may need regular medical treatment to manage their symptoms and avoid complications.
It’s important that you keep your baby’s vaccinations current to help avoid infections and ensure they take all medications as prescribed to manage their condition and support their best quality of life.
Avoiding triggers, like extreme heat or cold, can also help prevent painful episodes called sickle cell crises throughout life.
If a baby has sickle cell anemia, is the pregnancy at high risk?
According to the American College of Obstetricians and Gynecologists (ACOG), women who are carriers of the sickle cell trait may have healthy pregnancies. If your baby tests positive for having SCA, you and your doctor will work together to determine the risk status of your pregnancy.
Are you tested for sickle cell at birth?
According to the
Is sickle cell anemia detected before or after birth?
If you opt to have genetic testing, amniocentesis, or CVS, you may learn if your baby has SCA before they are born. Otherwise, your child is screened at birth.
If you and your partner carry the sickle cell trait, there’s a 25% chance your baby may be born with SCA. Your doctor may refer you to a genetic counselor for an additional risk assessment and options for the next steps.
Even if you are not tested during pregnancy, your child’s status can be detected after birth through routine hemoglobin disorder testing. Early detection is important in making sure a child with SCA can get the care they need to manage the condition.