Hematologist
CION Cancer Clinics
Prenatal diagnosis for thalassaemia and sickle cell | CION Cancer Clinics
If both parents carry a thalassaemia or sickle cell gene, each pregnancy has a 1 in 4 chance of an affected baby. Prenatal diagnosis tests the baby during pregnancy, most often by CVS near the end of the first three months, or by amniocentesis a little later. Both parents usually need DNA tests first. This guide explains the steps, what the result can and cannot tell you, and the questions to ask. At CION Cancer Clinics, our haematologist cares for anaemia, bleeding, clotting and inherited blood disorders, with ArogyaSri, CGHS and cashless insurance accepted.
BP
Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
17+specialists on panel
15,000+patients treated
35+centres across Telangana & AP
4.8★ / 800+Google rating
On this page
- What is prenatal diagnosis for thalassaemia or sickle cell?
- What happens between a carrier report and a result?
- What can the baby's result show?
- What do the words on these reports mean?
- What do families often get wrong about testing in pregnancy?
- What should you ask, and what can this test not tell you?
- How does testing early compare with testing late?
- Common questions about prenatal diagnosis
The short answer
What is prenatal diagnosis for thalassaemia or sickle cell?
Prenatal diagnosis is a test on the baby, done during pregnancy, to find out whether the baby has inherited a serious blood disorder such as thalassaemia major or sickle cell disease. It is offered when both parents carry a changed haemoglobin gene, because each pregnancy then carries a 1 in 4 chance that the baby inherits two changed genes.
How the sample is taken
The most common test in early pregnancy is chorionic villus sampling, or CVS. A thin needle takes a tiny piece of the placenta, which carries the same genes as the baby. It is usually done near the end of the first three months. Later in pregnancy, amniocentesis takes a small amount of the fluid around the baby instead. The lab then reads the baby's DNA.
Why the parents are tested first
The lab looks for the exact gene changes each parent carries. So both of you usually need a DNA test on your own blood before, or very early in, the pregnancy. Without the parents' results, the baby's sample may not give a clear answer, and there may not be time to repeat it.
Who it is not for
If only one parent is a carrier, the baby cannot have thalassaemia major or sickle cell disease from these genes, and a procedure is rarely needed. It is also a personal choice. Some couples decide not to test at all, and that decision deserves the same respect.
This page explains the process. It cannot tell you your own risk. That comes from both partners' reports, read together.The pathway
What happens between a carrier report and a result?
-
Both partners have a carrier test
A simple blood test, often called HPLC or Hb variant analysis, shows whether each of you carries a changed haemoglobin gene. If you are already pregnant, the partner's test should be done within days, not weeks.
-
Genetic counselling
A counsellor or haematologist explains what your two reports mean together, what the chances are for this pregnancy, and what your choices are. You can bring your parents or in-laws if that helps.
-
DNA testing of both parents
The lab identifies the exact gene change each of you carries. This is the key that lets the lab read the baby's sample accurately.
-
The procedure
An obstetrician trained in foetal medicine takes the sample under ultrasound guidance. Most women go home the same day.
-
The result and what comes next
The result is explained in person. The next steps depend on what it shows and on what you, as a couple, decide.
Not sure whether this applies to you?
Ask an oncologistThe result
What can the baby's result show?
There are three broad answers, and sometimes no clear answer. Each one is explained to you face to face, never only on paper.
Not affected, not a carrier
The baby has inherited no changed gene from either parent. The pregnancy continues with routine antenatal care.
A carrier, like a parent
The baby has one changed gene. Carriers are usually healthy and do not need treatment. The child should know this when they are older, before they plan their own family.
Affected
The baby has inherited two changed genes and is likely to have the disorder. How severe it will be is not always clear from DNA alone.
What you will be offered
- Time with a haematologist to understand the condition
- A discussion of continuing or ending the pregnancy
- Support whichever way you decide
No clear answer
Sometimes the sample is too small or mixed with the mother's cells. The team will explain whether a repeat test is possible in time.
This is uncommon, and one reason early testing matters.On your report
What do the words on these reports mean?
- Carrier or trait
- You have one changed haemoglobin gene. You are usually well, but you can pass the gene to your child.
- HbA2
- A type of haemoglobin. A raised level on HPLC often points to beta thalassaemia trait.
- HbS
- The sickle haemoglobin. If it appears on your report, you carry the sickle gene or have sickle cell disease.
- Mutation
- The exact change in the gene. The lab needs each parent's mutation to read the baby's sample.
- Maternal cell contamination
- The mother's cells mixed into the sample. Labs check for it, because it can hide the baby's true result.
Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Commonly believed
What do families often get wrong about testing in pregnancy?
"Our first child is healthy, so the next one will be too."
The chance is the same in every pregnancy. A healthy first child does not change the odds for the second. Each pregnancy is tested on its own if you want to know.
"We are from the same community, so we cannot both be carriers."
It is the other way round. Carrier genes are more common within some communities, and marriage within the family raises the chance that both partners carry the same change.
"The test will harm the baby."
CVS and amniocentesis carry a small risk of miscarriage, and that risk should be explained to you honestly. In experienced hands, most pregnancies continue normally. You weigh that small risk against the value of knowing.
"If we test, we will be pushed to end the pregnancy."
The result gives you information, not an instruction. What you do with it is your decision as a couple. A good counsellor will support either choice without judgement.
Being straight with you
What should you ask, and what can this test not tell you?
The test tells you which genes the baby has inherited. It does not tell you exactly how a child with an affected result will grow up. Two children with the same gene changes can need very different levels of care, and a DNA report cannot promise either the mild end or the severe end.
Questions worth asking before the procedure
Ask whether both parents' mutations are already known. Ask who takes the sample, how many of these procedures they do, and which lab reads it. Ask how long the result usually takes and who will explain it to you. Ask what happens if the sample does not give a clear answer.
Where CION fits in
CION does not perform CVS or amniocentesis. Our haematology team can read your carrier reports with you, explain what the two results mean together, and help you reach a qualified foetal medicine centre. If the baby is affected, we can talk you through what living with the condition involves, so your decision is an informed one.
If you are reading this late in pregnancy
Testing is still possible later, but the options narrow. Speak to your obstetrician this week rather than waiting for the next routine visit.
Timing
How does testing early compare with testing late?
Planned before or early in pregnancy
Arranged late in pregnancy
Parents' DNA is ready before the sample is taken
Parents' DNA and the baby's sample may be rushed together
CVS is usually possible
Amniocentesis or a cord blood sample may be the only choice
Time to repeat a test if the first gives no answer
Little or no time to repeat
More time to think and talk as a family
Decisions made under legal and medical time limits
Questions we are asked
Common questions about prenatal diagnosis
Both of us are thalassaemia carriers and I am pregnant. What do we do first?
Contact your obstetrician straight away and ask for genetic counselling. Both of you will usually need a DNA test to find your exact gene changes. Doing this quickly keeps CVS open as an option. Bring both carrier reports to every appointment so nobody has to repeat a test that is already done.
Is CVS or amniocentesis risky for the baby?
Both carry a small risk of miscarriage. The doctor doing the procedure should tell you the figure for their own practice. Most pregnancies continue without any problem. The risk is one part of the decision, alongside how much knowing the result matters to you as a couple.
Only I am a carrier. Does my baby need this test?
Usually not. If your partner's test is clearly normal, the baby cannot inherit thalassaemia major or sickle cell disease from these genes. Make sure your partner's test was the right kind, because a routine blood count alone can miss a carrier. Your haematologist can check both reports for you.
Can we test for sickle cell disease the same way?
Yes. The same procedures and the same approach work for sickle cell disease and for combinations such as sickle beta thalassaemia. The lab needs to know which gene changes each parent carries. Couples from tribal communities where the sickle gene is common should ask about this early in pregnancy.
Does this test tell us whether the baby is a boy or a girl?
No. In India, revealing the sex of a baby before birth is against the law, and prenatal diagnosis for a blood disorder is only done to look for that disorder. The report will say whether the baby is affected, a carrier or unaffected, and nothing else.
What if the baby is affected?
You will be offered time with a haematologist and a counsellor to understand the condition, its treatment and what daily life involves. Some couples continue the pregnancy and plan for care. Others choose to end it within the legal limits. Both are valid choices, and you should not be rushed.
Can we avoid this next time?
Some couples choose IVF with testing of embryos before one is placed in the womb, so that only an unaffected embryo is used. It is expensive and not suited to everyone. Others choose to test early in each natural pregnancy. A counsellor can help you compare the two.
Is prenatal diagnosis covered by any scheme?
Coverage varies. Some government programmes for thalassaemia and sickle cell support screening and counselling, and rules change from year to year. Ask the centre what applies to you, and check the current rules for Aarogyasri, PM-JAY and your insurer before the procedure.
Your Haematologist
Meet CION's haematologist. One specialist for your blood report and your plan.
Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Sources
- NHS — Chorionic villus sampling (CVS)
- NHS — Amniocentesis
- NHS — Thalassaemia
- National Heart, Lung, and Blood Institute — Thalassemia
- National Health Mission — Sickle cell mission portal
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Both Partners Are Carriers: What the Odds MeanWhat the chance means for each pregnancyChorionic Villus Sampling and Amniocentesis ExplainedThe two procedures and their timing, side by sideGenetic Counselling for Haemoglobin DisordersWhat happens in a counselling sessionIVF and Preimplantation Testing for ThalassaemiaTesting embryos before a pregnancy beginsCarrier Screening and Genetic CounsellingThe full guide to carrier testing
Talk to us
Holding two carrier reports?
Tell us what the reports say. A CION haematologist will read them with you and help you reach the right foetal medicine centre.