Genetic Testing FAQs — NIPT, PGT-A, PGT-M, Amniocentesis | FertilityConnect

Question 1

What is NIPT?

Dr Vidhu D · Accepted Answer

NIPT (Non-Invasive Prenatal Testing) is a blood test done on the pregnant woman that analyses fragments of the baby's DNA circulating in her bloodstream (cell-free fetal DNA or cfDNA). It screens for chromosomal conditions including Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), Patau syndrome (Trisomy 13), and sex chromosome abnormalities. It is a screening test, not a diagnostic test — a positive result means increased risk, not a confirmed diagnosis. ACOG recommends NIPT as an option for all pregnant women, with particular value for those at higher risk.

Question 2

How accurate is NIPT?

Dr Vidhu D · Accepted Answer

NIPT has very high sensitivity and specificity for the three main trisomies. For Down syndrome (Trisomy 21): sensitivity approximately 99%, specificity approximately 99.9%. For Trisomy 18 and 13: sensitivity 97–99%. However, these figures apply to high-prevalence populations — in low-risk populations, the positive predictive value (the chance that a positive result is a true positive) can be as low as 40–90% depending on maternal age and the condition screened. A positive NIPT should always be confirmed by diagnostic testing (amniocentesis or CVS) before any clinical decision is made. Please consult a genetic counsellor or foetal medicine specialist to interpret your specific result.

Question 3

When should NIPT be done?

Dr Vidhu D · Accepted Answer

NIPT can be performed from 10 weeks of pregnancy onwards. It is most commonly offered between 10 and 14 weeks, often alongside the first trimester ultrasound (nuchal translucency scan). Testing before 10 weeks may result in insufficient fetal fraction (the proportion of fetal DNA in the sample), leading to test failure. There is no strict upper gestational age limit — NIPT can be performed in the second trimester if not done earlier. Your obstetrician will advise the optimal timing based on your specific pregnancy and risk factors.

Question 4

What conditions does NIPT detect?

Dr Vidhu D · Accepted Answer

Standard NIPT screens for: Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome), Trisomy 13 (Patau syndrome), and sex chromosome aneuploidies (Turner syndrome, Klinefelter syndrome, XXX, XYY). Expanded NIPT panels offered by some laboratories also screen for: microdeletion syndromes (DiGeorge/22q11.2 deletion, Prader-Willi, Angelman, Cri-du-chat), rare autosomal trisomies, and copy number variants. Expanded panels have lower positive predictive values and higher false positive rates. Discuss the specific panel offered with your obstetrician or genetic counsellor before testing.

Question 5

Can NIPT detect Down syndrome?

Dr Vidhu D · Accepted Answer

Yes — NIPT is the most sensitive screening test available for Down syndrome (Trisomy 21), with a detection rate of approximately 99% and a false positive rate below 0.1% (ACOG 2020). It significantly outperforms first trimester combined screening (nuchal translucency + blood tests) for Down syndrome detection. However, NIPT is a screening test — a high-risk result requires confirmation by amniocentesis or CVS (chorionic villus sampling), which are diagnostic tests that examine the baby's chromosomes directly. Please consult your obstetrician or foetal medicine specialist for guidance.

Question 6

Is NIPT safe during pregnancy?

Dr Vidhu D · Accepted Answer

Yes — NIPT is completely safe for both mother and baby. It requires only a maternal blood sample (a standard venepuncture) and carries no risk of miscarriage or harm to the pregnancy. This is a key advantage over invasive diagnostic tests such as amniocentesis and CVS, which carry a small but real procedural risk. The blood sample is processed in a laboratory to isolate and analyse cell-free fetal DNA. There are no known side effects or risks associated with NIPT beyond those of a routine blood test.

Question 7

What is the difference between NIPT and amniocentesis?

Dr Vidhu D · Accepted Answer

NIPT is a non-invasive screening test — a maternal blood sample that analyses fetal DNA fragments. It is safe, carries no miscarriage risk, and is highly accurate for common trisomies but cannot give a definitive diagnosis. Amniocentesis is an invasive diagnostic test — a needle is inserted through the abdomen into the amniotic sac under ultrasound guidance to obtain a sample of amniotic fluid containing fetal cells. It provides a definitive chromosomal diagnosis and detects a much wider range of conditions. It carries a small miscarriage risk (approximately 0.1–0.3% per ACOG 2021). The typical pathway: NIPT first for screening, amniocentesis if NIPT is high-risk and diagnostic confirmation is needed.

Question 8

Can NIPT detect baby gender?

Dr Vidhu D · Accepted Answer

Yes — NIPT identifies sex chromosomes (XX or XY) as part of its standard analysis, which reveals fetal sex. In India, disclosure of fetal sex is illegal under the PCPNDT Act 1994 and applies equally to NIPT. Laboratories and clinicians in India are legally prohibited from reporting or disclosing fetal sex from NIPT results. FertilityConnect complies fully with the PCPNDT Act. If you are outside India, your clinician can advise whether sex chromosome results will be reported based on local regulations.

Question 9

How long do NIPT results take?

Dr Vidhu D · Accepted Answer

NIPT results typically take 7–14 calendar days from the date the blood sample reaches the laboratory. Some laboratories offer expedited results in 5–7 days. Turnaround times vary by laboratory and whether the sample needs international shipping. If results are taking longer than expected, the most common reason is insufficient fetal fraction (low fetal DNA in the sample), which may require a repeat sample. Your obstetrician's office or the laboratory will notify you of any delay. Contact your doctor if you have not received results after 14 days.

Question 10

Can NIPT be wrong?

Dr Vidhu D · Accepted Answer

Yes — NIPT can produce both false positive results (test says high-risk but the baby is chromosomally normal) and false negative results (test says low-risk but the baby is affected). False positives are more common than false negatives. Important reasons for NIPT errors include: confined placental mosaicism (the placenta has a chromosomal abnormality that the baby does not), vanishing twin, low fetal fraction, maternal chromosomal abnormality, and maternal cancer. This is precisely why a high-risk NIPT result must always be confirmed with amniocentesis or CVS before any irreversible decision is made. Please consult a genetic counsellor or foetal medicine specialist.

Question 11

What causes false positive NIPT results?

Dr Vidhu D · Accepted Answer

The most common causes of false positive NIPT results: (1) Confined placental mosaicism — the placenta has a chromosomal abnormality that the developing baby does not share. (2) Vanishing twin — a co-twin that stopped developing early can contribute abnormal DNA. (3) Maternal chromosomal abnormality or mosaicism. (4) Maternal cancer — some malignancies shed abnormal DNA into the bloodstream. (5) Low fetal fraction with technical artefact. False positives are more common for rare conditions (microdeletions) than for the main trisomies. All high-risk results must be confirmed diagnostically. Please consult a foetal medicine specialist or genetic counsellor.

Question 12

What causes false negative NIPT results?

Dr Vidhu D · Accepted Answer

False negative NIPT results (missed affected pregnancies) are rare but occur due to: low fetal fraction (insufficient fetal DNA for accurate analysis), confined placental mosaicism where the placental cells analysed do not reflect the fetal chromosomes, and technical laboratory limitations. The false negative rate for Down syndrome with NIPT is approximately 0.1% (approximately 1 in 1000 affected pregnancies missed). A normal NIPT result significantly reduces but does not eliminate chromosomal risk. If clinical findings (ultrasound abnormalities, raised nuchal translucency) are concerning despite a normal NIPT, diagnostic testing should still be discussed with your foetal medicine specialist.

Question 13

What is low fetal fraction in NIPT?

Dr Vidhu D · Accepted Answer

Fetal fraction is the percentage of cell-free DNA in the maternal blood sample that comes from the placenta (representing fetal DNA). Most laboratories require a minimum fetal fraction of 3–4% for reliable NIPT analysis. Low fetal fraction increases the risk of test failure or inaccurate results. Common causes: testing too early (before 10 weeks), high maternal BMI (excess maternal DNA dilutes fetal fraction), incorrect sample handling, or rarely fetal chromosomal abnormality (very low fetal fraction can itself be a risk indicator for Trisomy 13 or 18). If your NIPT fails due to low fetal fraction, your doctor will advise on timing a repeat sample — usually waiting 1–2 weeks.

Question 14

Why did my NIPT fail?

Dr Vidhu D · Accepted Answer

NIPT failure (no result) most commonly occurs due to: low fetal fraction (insufficient fetal DNA — most common cause), sample handling or transport issues (temperature, timing), laboratory technical failure, or very early gestational age at the time of testing. An overall NIPT failure rate of 1–5% is expected across laboratories. Importantly, a higher rate of test failure is associated with fetal aneuploidy — particularly Trisomy 13 and 18 — because these conditions are associated with very low fetal fraction. If your test fails, please consult your obstetrician before simply repeating it, as the failure itself may be clinically informative and warrant ultrasound review.

Question 15

Should I repeat NIPT after inconclusive results?

Dr Vidhu D · Accepted Answer

Whether to repeat NIPT after an inconclusive result depends on the reason for the inconclusive report. If the cause was low fetal fraction due to early testing, repeating after 1–2 weeks is reasonable. If the repeat also fails, or if there are any ultrasound concerns, diagnostic testing (amniocentesis or CVS) is the more appropriate next step — it provides definitive results. Do not repeatedly retry NIPT if diagnostic answers are urgently needed. Please discuss the specific reason for your inconclusive result with your obstetrician or foetal medicine specialist, who can advise the best next step for your individual situation.

Question 16

What does high-risk NIPT mean?

Dr Vidhu D · Accepted Answer

A high-risk NIPT result means the test has detected an increased probability of a chromosomal condition in the pregnancy — it does not confirm that the baby has that condition. Depending on the condition screened and your specific risk factors, a high-risk result may have a positive predictive value (true positive rate) of 40–95%. The correct next step after a high-risk NIPT is always diagnostic confirmation via amniocentesis or CVS. Please do not make any irreversible decisions based on NIPT alone. Your obstetrician will refer you to a foetal medicine specialist or genetic counsellor who will explain the result and guide next steps.

Question 17

What does low-risk NIPT mean?

Dr Vidhu D · Accepted Answer

A low-risk NIPT result means the test did not detect significant evidence of the chromosomal conditions screened for. This is very reassuring — NIPT has a very low false negative rate for the main trisomies (Down, Edwards, Patau syndromes). However, low-risk does not mean the baby is guaranteed to be chromosomally normal or free of all birth defects. NIPT screens only for specific conditions — it does not detect structural birth defects, single gene disorders, or most rare chromosomal conditions. A detailed anatomy ultrasound at 18–20 weeks remains important even after a low-risk NIPT result.

Question 18

Can ultrasound be normal after abnormal NIPT?

Dr Vidhu D · Accepted Answer

Yes — and this occurs relatively commonly, most often because of a false positive NIPT result (due to confined placental mosaicism or other causes) rather than because the ultrasound has missed an abnormality. In this situation, diagnostic confirmation by amniocentesis or CVS is essential — it is the only way to determine whether the NIPT result or the normal ultrasound reflects the true fetal chromosomal status. A normal ultrasound is reassuring but does not exclude all chromosomal abnormalities (particularly Trisomy 21, which may have subtle or no ultrasound markers). Please consult a foetal medicine specialist for combined assessment.

Question 19

Can IVF affect NIPT results?

Dr Vidhu D · Accepted Answer

IVF itself does not affect NIPT accuracy. However, specific IVF-related factors warrant awareness: egg donation pregnancies — NIPT analyses DNA from the placenta (which reflects the egg donor's genetic contribution, not the recipient). Maternal age risk tables used for result interpretation should reflect the egg donor's age, not the recipient's. Twin IVF pregnancies — NIPT in twins has reduced sensitivity and different interpretation thresholds. PGT-A prior to transfer — NIPT still provides value even after PGT-A, but interpretation differs (see separate FAQ). Please ensure your laboratory and clinician are informed of your IVF history before testing.

Question 20

Do I still need NIPT after PGT-A?

Dr Vidhu D · Accepted Answer

PGT-A and NIPT screen for similar chromosomal abnormalities but at different stages and with different limitations. PGT-A tests the embryo before implantation at the trophectoderm biopsy stage. NIPT tests the pregnancy after implantation, sampling DNA from the placenta. After a successful euploid PGT-A transfer, NIPT remains useful because: (1) PGT-A has a 1–5% error rate; (2) new chromosomal errors can arise after the biopsy stage; (3) NIPT provides independent reassurance. ACOG and ASRM do not recommend against NIPT after PGT-A — the decision should be made with your obstetrician and genetic counsellor based on your individual history and anxiety level.

Question 21

What is amniocentesis?

Dr Vidhu D · Accepted Answer

Amniocentesis is a diagnostic prenatal procedure in which a fine needle is inserted through the mother's abdomen, under continuous ultrasound guidance, into the amniotic sac to withdraw a small sample of amniotic fluid. This fluid contains fetal cells that are grown in culture and analysed for chromosomal abnormalities, genetic conditions, or infections. Unlike NIPT (a screening test), amniocentesis provides a definitive chromosomal diagnosis. It is typically offered when there is a high-risk screening result, advanced maternal age, abnormal ultrasound findings, or a family history of a specific genetic condition. Please consult a foetal medicine specialist or genetic counsellor.

Question 22

Is amniocentesis painful?

Dr Vidhu D · Accepted Answer

Most women describe amniocentesis as causing mild to moderate discomfort rather than significant pain. The sensation is typically pressure from the needle passing through the abdominal wall, and a cramping feeling as the amniotic fluid is withdrawn. The procedure takes approximately 2–5 minutes. Local anaesthetic cream or injection is used by some clinicians to numb the skin. Mild uterine cramping and light spotting may occur for 24–48 hours afterwards and is normal. If pain is severe, persistent, or accompanied by fever or heavy bleeding after the procedure, contact your obstetrician immediately.

Question 23

Is amniocentesis risky?

Dr Vidhu D · Accepted Answer

Amniocentesis is associated with a small but real procedural risk. Per ACOG 2021: the procedure-related miscarriage risk is approximately 0.1–0.3% (1 in 300–1000 procedures) when performed by an experienced operator under continuous ultrasound guidance. Other risks include: transient amniotic fluid leakage (rare), infection (very rare, less than 0.1%), and Rh sensitisation in Rh-negative mothers (prevented by anti-D immunoglobulin). The risk is substantially lower when performed in a foetal medicine centre with high procedure volumes. Please consult a foetal medicine specialist who performs amniocentesis regularly — operator experience significantly affects risk.

Question 24

When is amniocentesis done?

Dr Vidhu D · Accepted Answer

Amniocentesis is most commonly performed between 15 and 20 weeks of pregnancy, when there is sufficient amniotic fluid and the risk is lowest. Earlier amniocentesis (before 15 weeks) is associated with higher complication rates and is generally not recommended. In specific circumstances (such as late diagnosis of a structural abnormality or late referral), amniocentesis can be performed after 20 weeks, though this affects the timing of results and subsequent decision-making. CVS (chorionic villus sampling) is the alternative for earlier testing (10–14 weeks). Your foetal medicine specialist will advise on timing based on your gestational age and clinical situation.

Question 25

Can amniocentesis confirm NIPT?

Dr Vidhu D · Accepted Answer

Yes — amniocentesis is the gold standard diagnostic test for confirming or refuting a high-risk NIPT result. NIPT analyses cell-free DNA fragments from the placenta and can be wrong (particularly due to confined placental mosaicism). Amniocentesis analyses actual fetal cells from the amniotic fluid and provides a definitive chromosomal result. ACOG recommends that invasive diagnostic testing (amniocentesis or CVS) be offered to all women with a high-risk NIPT result before any clinical decision is made. Please consult a foetal medicine specialist or genetic counsellor who will explain what the specific NIPT result means and guide next steps.

Question 26

What disorders can amniocentesis detect?

Dr Vidhu D · Accepted Answer

Amniocentesis can detect: all chromosomal abnormalities (trisomies, monosomies, deletions, duplications) by standard karyotype; submicroscopic chromosomal abnormalities by chromosomal microarray (detects 3–5% additional clinically significant findings beyond standard karyotype); specific single gene disorders if targeted testing is requested (e.g. cystic fibrosis, thalassemia, SMA); congenital infections (CMV, toxoplasma) by PCR; and neural tube defects (via alpha-fetoprotein levels). It cannot detect all genetic conditions — only conditions for which specific tests are ordered. Discuss the appropriate test panel with your foetal medicine specialist or genetic counsellor.

Question 27

What is the miscarriage risk with amniocentesis?

Dr Vidhu D · Accepted Answer

The procedure-related pregnancy loss rate with amniocentesis is approximately 0.1–0.3% per ACOG 2021 — meaning 1 in 300 to 1 in 1000 procedures. This risk is significantly lower than quoted in older literature, reflecting improved ultrasound guidance and operator technique. Risk is lowest when performed: between 15–20 weeks, by a experienced foetal medicine specialist, in a high-volume centre, using continuous ultrasound guidance. The decision to proceed requires weighing the diagnostic information gained against the procedural risk. A genetic counsellor can help you understand this risk in the context of your specific situation.

Question 28

How long do amniocentesis results take?

Dr Vidhu D · Accepted Answer

Results timing depends on the analysis method: Rapid FISH or QF-PCR (preliminary result for main chromosomes 13, 18, 21, X, Y): 2–3 working days. Standard karyotype (full chromosome picture, 46 chromosomes): 10–14 working days. Chromosomal microarray: 2–3 weeks. Single gene disorder testing (e.g. thalassemia): 2–4 weeks depending on the test. Most centres provide the rapid result first (within days) to allow earlier decision-making, followed by the complete karyotype. Ask your foetal medicine specialist which tests have been ordered and what the expected turnaround is for each.

Question 29

Should I do amniocentesis after positive NIPT?

Dr Vidhu D · Accepted Answer

ACOG and ESHRE both recommend offering diagnostic confirmation (amniocentesis or CVS) to all women with a high-risk NIPT result before any clinical decision is made. Whether to proceed is ultimately your personal choice. Some couples choose to proceed directly to diagnostic testing to have certainty; others may feel the NIPT result is sufficient for their decision-making; some choose to continue the pregnancy regardless and may decline further testing. There is no single correct answer. A genetic counsellor is invaluable in this situation — they will explain the specific positive predictive value for your result, the procedural risk, and help you make an informed, unpressured decision.

Question 30

What is the difference between CVS and amniocentesis?

Dr Vidhu D · Accepted Answer

Both are invasive diagnostic tests that provide definitive chromosomal results. CVS (Chorionic Villus Sampling): performed at 10–14 weeks, samples placental tissue (chorionic villi), results available earlier in pregnancy, slightly higher miscarriage risk (0.5–1%), and cannot test for neural tube defects. Amniocentesis: performed at 15–20 weeks, samples amniotic fluid (fetal cells), slightly lower miscarriage risk (0.1–0.3%), and can test for neural tube defects. CVS is preferred when earlier results are needed. Amniocentesis is preferred when later gestational age, or when neural tube defect testing is required. Your foetal medicine specialist will advise which is more appropriate for your situation.

Question 31

Is CVS safer than amniocentesis?

Dr Vidhu D · Accepted Answer

CVS carries a slightly higher procedure-related miscarriage risk than amniocentesis — approximately 0.5–1.0% for CVS versus 0.1–0.3% for amniocentesis per ACOG 2021. However, CVS is performed earlier (10–14 weeks) which is its primary advantage, allowing earlier decision-making if needed. In very experienced hands at specialist foetal medicine centres, the risk difference between the two procedures may be smaller. The choice depends on gestational age, clinical indication, and the couple's specific situation and preferences. Please consult a foetal medicine specialist who performs both procedures to discuss the most appropriate option for you.

Question 32

Can amniocentesis detect autism?

Dr Vidhu D · Accepted Answer

No — amniocentesis cannot detect autism. Autism Spectrum Disorder (ASD) does not have a single identifiable chromosomal or genetic cause in the vast majority of cases. It is a complex neurodevelopmental condition influenced by many genetic and environmental factors, most of which are not detectable by standard chromosomal analysis. Some specific genetic syndromes associated with autism (fragile X syndrome, Phelan-McDermid syndrome, some 22q11.2 deletions) can be identified if specifically tested for — but these account for only a small minority of autism cases. There is currently no prenatal test that can reliably predict whether a child will have autism.

Question 33

What is chromosomal microarray testing?

Dr Vidhu D · Accepted Answer

Chromosomal microarray analysis (CMA) is a high-resolution genetic test that detects submicroscopic chromosomal deletions and duplications (copy number variants or CNVs) that are too small to be seen by standard karyotype. It detects approximately 3–5% additional clinically significant findings over standard karyotype in pregnancies with structural abnormalities, and 1–1.7% additional findings in low-risk pregnancies. ACOG recommends offering CMA in addition to karyotype when a structural abnormality is found on ultrasound. In IVF, CMA is the basis for PGT-A (embryo chromosome testing). Please discuss with your foetal medicine specialist or genetic counsellor whether microarray is recommended for your specific situation.

Question 34

What is fetal karyotyping?

Dr Vidhu D · Accepted Answer

Fetal karyotyping is the analysis of the chromosomes obtained from fetal cells (via amniocentesis or CVS). Chromosomes are stained, photographed, and arranged in pairs to produce a karyogram showing all 46 chromosomes. It detects major numerical abnormalities (trisomies, monosomies) and large structural rearrangements (translocations, inversions). Standard karyotyping has a resolution limit of approximately 5–10 megabases — smaller abnormalities require chromosomal microarray. The karyotype result is reported as a formula: 46,XX (normal female), 47,XY+21 (male with Down syndrome), etc. Please have your result explained by your foetal medicine specialist or genetic counsellor.

Question 35

What happens if prenatal testing is abnormal?

Dr Vidhu D · Accepted Answer

An abnormal prenatal test result opens a series of decisions, all of which are yours to make at your own pace with full support. Steps: (1) Genetic counselling — to fully understand what the specific abnormality means for the baby's health, development, and prognosis. (2) Detailed ultrasound — to look for structural abnormalities associated with the diagnosis. (3) Specialist consultation — paediatric cardiologist, neonatologist, or paediatric specialist depending on the diagnosis. (4) Decision-making about the pregnancy — all options are valid and deeply personal. You should never feel rushed. A genetic counsellor and a foetal medicine specialist are your most important supports at this stage. Please consult both.

Question 36

What is PGT-A?

Dr Vidhu D · Accepted Answer

PGT-A (Preimplantation Genetic Testing for Aneuploidy) is a genetic test performed on IVF embryos before transfer to identify which embryos have the correct number of chromosomes (euploid) and which have abnormal chromosome numbers (aneuploid). A small biopsy of 5–10 cells is taken from the outer layer of each blastocyst (Day 5–6) and sent for chromosomal analysis using Next-Generation Sequencing (NGS). Only chromosomally normal embryos are selected for transfer. The goal is to improve implantation rates, reduce miscarriage, and reduce the time to successful pregnancy.

Question 37

How does PGT-A work?

Dr Vidhu D · Accepted Answer

PGT-A follows this sequence: (1) Standard IVF stimulation and egg retrieval. (2) Fertilisation and embryo culture to blastocyst stage (Day 5–6). (3) Trophectoderm biopsy — 5–10 cells removed from the outer layer (which forms the placenta) without disturbing the inner cell mass (which forms the baby). (4) Embryo vitrification (freezing) — the biopsied embryos are frozen while awaiting results. (5) Genetic analysis — typically Next-Generation Sequencing (NGS) — analyses all 23 chromosome pairs. (6) Frozen embryo transfer (FET) — only euploid embryos are transferred in a subsequent cycle. Results take approximately 7–14 days.

Question 38

Is PGT-A worth it?

Dr Vidhu D · Accepted Answer

Whether PGT-A is worth it depends on your specific situation. It is most clearly beneficial for: women aged 38 and over (where aneuploidy rates are high — 60–80%), recurrent implantation failure (2+ failed transfers with good embryos), recurrent pregnancy loss (3+ miscarriages), and severe male factor infertility with high DNA fragmentation. In women under 35 with good prognosis, PGT-A may improve per-transfer success rates but has less impact on cumulative live birth rates since euploid embryos are available anyway. PGT-A adds cost and the biopsy step. Please consult your fertility specialist, who can advise whether PGT-A is likely to benefit your specific situation.

Question 39

Does PGT-A improve IVF success?

Dr Vidhu D · Accepted Answer

PGT-A consistently improves per-transfer live birth rates — transferring only euploid embryos means each transfer has the best possible chance. Studies show per-transfer live birth rates of 50–65% for euploid embryo transfers regardless of age (ESHRE 2023). However, PGT-A does not improve overall (cumulative) live birth rates in good-prognosis young patients, because aneuploid embryos in younger women often self-correct or would not implant anyway. The clearest benefit is in women 38+ and those with recurrent failure, where identifying the euploid embryos from a pool with mostly aneuploid ones prevents futile transfers. Discuss your specific situation with your fertility specialist.

Question 40

Does PGT-A reduce miscarriage?

Dr Vidhu D · Accepted Answer

Yes — this is one of the strongest and most consistent benefits of PGT-A. Aneuploidy is the cause of 50–70% of early miscarriages. By selecting only euploid embryos for transfer, PGT-A significantly reduces the miscarriage rate after embryo transfer. Studies consistently show miscarriage rates of 5–10% after euploid embryo transfer, compared to 15–25% without PGT-A (ESHRE 2023). This benefit is most pronounced in women with recurrent pregnancy loss and women aged 38+. PGT-A is one of the most evidence-supported interventions for recurrent miscarriage associated with recurrent implantation failure.

Question 41

Who should do PGT-A?

Dr Vidhu D · Accepted Answer

ASRM 2023 identifies the strongest indications for PGT-A as: women aged 38 and over (high baseline aneuploidy rate), recurrent implantation failure (2+ failed transfers with good-quality embryos), recurrent pregnancy loss (3+ miscarriages), severe male factor infertility, and previous pregnancy with chromosomal abnormality. PGT-A is also used for family balancing (where legal) as sex is identified alongside chromosome status. For women under 35 with good prognosis and no prior failures, PGT-A is optional and its benefit on cumulative outcomes is less clear. Please consult your fertility specialist for an individualised recommendation.

Question 42

Can PGT-A guarantee a healthy baby?

Dr Vidhu D · Accepted Answer

No — PGT-A cannot guarantee a healthy baby, and no test can. PGT-A screens for chromosomal number errors (aneuploidy) only. It does not detect: single gene disorders (unless combined with PGT-M), structural birth defects, conditions arising from environmental factors, or conditions caused by very small chromosomal changes below the resolution of the test. Even after a euploid transfer, approximately 5–10% of pregnancies miscarry (from non-chromosomal causes), and approximately 3–5% of liveborn babies have some form of birth defect or genetic condition unrelated to chromosome number. A normal PGT-A result means the embryo has the correct number of chromosomes — it is a very reassuring finding but not a guarantee.

Question 43

How accurate is PGT-A?

Dr Vidhu D · Accepted Answer

PGT-A has a technical accuracy of approximately 95–98% for detecting aneuploid embryos using modern NGS platforms. The main sources of error are: allele dropout (technical failure to amplify DNA from all chromosomes), mosaicism (where some cells in the biopsy are euploid and others aneuploid), and biopsy sampling variability (the biopsied trophectoderm cells may not fully represent the inner cell mass). False positive rate (calling a euploid embryo aneuploid) is estimated at 1–2%. False negative rate (calling an aneuploid embryo euploid) is estimated at 1–3%. These figures come from studies using blinded validation, and accuracy continues to improve with platform development.

Question 44

Can PGT-A be wrong?

Dr Vidhu D · Accepted Answer

Yes — PGT-A can produce incorrect results, though this is uncommon. The most clinically important scenario is a false positive (a euploid embryo incorrectly called aneuploid and discarded). This is estimated to occur in 1–2% of embryos. Conversely, a false negative (aneuploid embryo called euploid and transferred) occurs in approximately 1–3% of cases. Mosaicism (mixed chromosomal populations within the embryo) is the most complex and contested issue — mosaic results occupy a grey zone between clearly euploid and clearly aneuploid. For this reason, ASRM recommends that PGT-A results be interpreted by an experienced embryologist and clinical geneticist alongside clinical context.

Question 45

What are euploid embryos?

Dr Vidhu D · Accepted Answer

Euploid embryos have the correct number of chromosomes — 46 chromosomes in 23 pairs (46,XX for female or 46,XY for male). Euploid embryos have the highest implantation potential and lowest miscarriage risk of any embryo category. Per-transfer live birth rates for euploid embryos are approximately 50–65% (ESHRE 2023), compared to 30–40% for untested embryos in the same age group. The proportion of euploid embryos declines with maternal age: approximately 60–70% of blastocysts are euploid in women under 35, declining to 20–30% in women aged 41–42. PGT-A identifies euploid embryos for preferential transfer.

Question 46

What are aneuploid embryos?

Dr Vidhu D · Accepted Answer

Aneuploid embryos have an abnormal number of chromosomes — either extra chromosomes (trisomy) or missing chromosomes (monosomy) in one or more pairs. Aneuploid embryos either fail to implant, cause a chemical pregnancy, or result in early miscarriage in the vast majority of cases. Some specific aneuploidies (Trisomy 21, 18, 13, and sex chromosome aneuploidies) can result in ongoing pregnancies. The proportion of aneuploid embryos increases steeply with maternal age — approaching 70–80% of blastocysts in women over 40. PGT-A identifies aneuploid embryos to avoid transfer of embryos that are very unlikely to result in a healthy live birth.

Question 47

What are mosaic embryos?

Dr Vidhu D · Accepted Answer

Mosaic embryos contain a mixture of chromosomally normal (euploid) cells and chromosomally abnormal (aneuploid) cells. They are detected in approximately 5–15% of biopsied blastocysts. The clinical significance of mosaicism is complex and debated. A mosaic embryo's potential depends on: the percentage of abnormal cells (low-level mosaicism <40% is more favourable than high-level >40%), which chromosome is involved, and whether the abnormal cells are in the trophectoderm (placenta-forming) or the inner cell mass (baby-forming). Mosaic embryos have lower implantation rates and higher miscarriage rates than fully euploid embryos but higher rates than fully aneuploid embryos. Please consult your fertility specialist and genetic counsellor before deciding.

Question 48

Should mosaic embryos be transferred?

Dr Vidhu D · Accepted Answer

The transfer of mosaic embryos is an active and evolving area of practice. ASRM 2023 and ESHRE 2023 position: mosaic embryo transfer may be considered when no fully euploid embryos are available, after thorough counselling. Key points: low-level mosaicism (<40% abnormal cells) carries a more favourable prognosis than high-level mosaicism. Some chromosomal mosaicisms are more concerning than others. Live birth rates from mosaic transfers are lower than from euploid transfers (approximately 30–40% vs 50–65%). Prenatal diagnostic testing (NIPT and amniocentesis) is recommended after a successful mosaic transfer to confirm fetal chromosomal status. Please consult your fertility specialist and genetic counsellor.

Question 49

Can mosaic embryos become healthy babies?

Dr Vidhu D · Accepted Answer

Yes — healthy babies have been born from mosaic embryo transfers, and published data from multiple centres confirm this. The mechanism by which this occurs is thought to involve self-correction: abnormal cells may be preferentially eliminated during development, or confined to placental rather than fetal tissue. However, not all mosaic embryos self-correct, and the risk of an ongoing pregnancy with chromosomal abnormality remains. Cumulative data from the PGDIS registry and published case series show healthy births from many types of mosaic embryos. Amniocentesis during the pregnancy is strongly recommended after a mosaic transfer. Please discuss your specific mosaic result with your fertility specialist and genetic counsellor.

Question 50

Does embryo biopsy damage embryos?

Dr Vidhu D · Accepted Answer

Trophectoderm biopsy at the blastocyst stage (Day 5–6) is considered safe with minimal damage to the embryo when performed by an experienced embryologist. The biopsy removes 5–10 cells from the trophectoderm (the outer layer that forms the placenta), not from the inner cell mass (which forms the baby). Studies comparing outcomes of biopsied versus non-biopsied embryos show no significant difference in implantation rates, live birth rates, or birth defect rates (ASRM 2023). Early cleavage-stage biopsy (Day 3) is no longer recommended because it is associated with worse outcomes — modern PGT uses only blastocyst biopsy.

Question 51

Why are all my embryos abnormal?

Dr Vidhu D · Accepted Answer

Finding all or most embryos aneuploid after PGT-A is distressing but not uncommon, particularly in women over 38. The most common reason is maternal age — aneuploidy rates increase steeply with age (approaching 80–90% in women over 42). Other contributing factors: very low ovarian reserve (fewer embryos means less chance of a euploid one in the sample), poor sperm quality or high sperm DNA fragmentation, and rarely, an underlying parental chromosomal abnormality. Recommended next steps: parental karyotyping (to rule out a structural chromosomal abnormality in either partner), sperm DNA fragmentation testing, and a full review with your fertility specialist and genetic counsellor about options including donor eggs or donor sperm.

Question 52

Can abnormal embryos self-correct?

Dr Vidhu D · Accepted Answer

Most aneuploid embryos do not self-correct in any clinically meaningful way. The concept of 'self-correction' is most relevant for mosaic embryos (where only some cells are abnormal) — there is evidence that abnormal cells can be preferentially eliminated in favour of normal cells during early development, particularly if abnormal cells are confined to the trophectoderm. Fully aneuploid embryos (where all cells carry the abnormality) do not self-correct — they either fail to implant, cause a chemical pregnancy, or in the case of viable trisomies (21, 18, 13, sex chromosome), result in an ongoing pregnancy with that chromosomal condition. Please do not transfer aneuploid embryos without specialist and genetic counsellor guidance.

Question 53

How long do PGT-A results take?

Dr Vidhu D · Accepted Answer

PGT-A results are typically available within 7–14 calendar days from the date of embryo biopsy. Most laboratories now routinely return results within 7–10 days. During this time, all biopsied embryos are vitrified (frozen) at the IVF laboratory and await results before transfer is planned. If results are delayed, the embryos remain safely stored — vitrification does not impose a time limit on storage. Once euploid embryos are identified, a frozen embryo transfer (FET) cycle is planned — usually in the subsequent menstrual cycle. Your fertility clinic will communicate results directly and schedule your transfer consultation.

Question 54

Does embryo grading matter after PGT-A?

Dr Vidhu D · Accepted Answer

Yes — embryo morphological grading (the visual quality score: AA, AB, BA, BB etc.) still provides additional prognostic information even after PGT-A confirms euploidy. Among euploid embryos, those with better morphological grades (higher inner cell mass and trophectoderm scores) have modestly higher implantation rates. However, the difference is smaller than it appears without PGT-A — even low-grade euploid embryos have meaningful implantation potential. ESHRE 2023 recommends transferring the highest-grade euploid embryo first. Do not discard low-grade euploid embryos — they still represent viable transfer options, particularly if higher-grade ones have already been used.

Question 55

Can genetically normal embryos still miscarry?

Dr Vidhu D · Accepted Answer

Yes — approximately 5–10% of euploid embryo transfers result in miscarriage. This occurs because chromosomal abnormality (aneuploidy) is the most common but not the only cause of miscarriage. Other causes include: endometrial receptivity issues (timing of transfer, thin lining, displaced implantation window), uterine abnormalities (polyps, fibroids, adhesions, septum), thrombophilia (antiphospholipid syndrome), immune factors, sperm DNA fragmentation, and unexplained causes. After a euploid embryo miscarriage, investigation should include ERA testing, hysteroscopy, thrombophilia screen, and sperm DNA fragmentation testing. Please consult your fertility specialist for a structured review.

Question 56

Why did my euploid embryo fail?

Dr Vidhu D · Accepted Answer

A failed euploid embryo transfer (no implantation) is one of the most frustrating outcomes in IVF. The embryo was chromosomally normal — so the cause lies elsewhere. Most likely causes: endometrial receptivity (the most common — including displaced implantation window detectable by ERA test), subclinical chronic endometritis (diagnosed by CD138 biopsy), uterine cavity abnormalities (polyps, fibroids, adhesions — diagnosed by hysteroscopy), suboptimal progesterone levels on the day of transfer, sperm DNA fragmentation, or thrombophilia. After one failed euploid transfer, a structured investigation is strongly recommended before the next transfer. Please consult your fertility specialist and request a dedicated review.

Question 57

Is PGT-A covered by insurance?

Dr Vidhu D · Accepted Answer

In India, PGT-A is not typically covered by health insurance — it is generally considered an elective add-on to IVF rather than a standard medical treatment. Costs vary by centre: PGT-A adds approximately Rs 50,000–1,50,000 to an IVF cycle depending on the number of embryos biopsied and the laboratory used. In some countries (UK, some US states) PGT-A may be partially or fully covered for specific indications (recurrent miscarriage, advanced maternal age). Check your specific insurance policy and consult your fertility clinic's finance team. For patients with recurrent pregnancy loss or repeated IVF failure, a cost-benefit discussion with your fertility specialist is worthwhile.

Question 58

What is PGT-M?

Dr Vidhu D · Accepted Answer

PGT-M (Preimplantation Genetic Testing for Monogenic disorders) is a specialised form of IVF-based genetic testing that screens embryos for a specific, known single-gene disorder present in the family. Unlike PGT-A (which screens for chromosome number), PGT-M identifies whether each embryo has inherited a specific gene mutation. Examples of conditions tested: thalassemia, sickle cell disease, cystic fibrosis, SMA (spinal muscular atrophy), Huntington's disease, BRCA1/2 mutations. Only embryos free of the specific mutation are selected for transfer, with the goal of preventing the condition from being passed to the next generation.

Question 59

Who should do PGT-M?

Dr Vidhu D · Accepted Answer

PGT-M is appropriate for couples where: both partners are carriers of an autosomal recessive condition (e.g. thalassemia, SMA, cystic fibrosis), one partner has or carries an autosomal dominant condition (e.g. Huntington's disease, BRCA1/2, myotonic dystrophy), one partner has an X-linked condition (e.g. haemophilia, Duchenne muscular dystrophy), or the family has a known serious genetic disorder with an identified causative mutation. A genetic counsellor should be consulted before embarking on PGT-M to confirm the indication, establish the mutation, and counsel on all reproductive options. Please consult a gynaecologist and genetic counsellor as the first step.

Question 60

What diseases can PGT-M detect?

Dr Vidhu D · Accepted Answer

PGT-M can in principle test for any single gene disorder for which the specific causative mutation has been identified in the family. Most commonly tested conditions include: Thalassemia (alpha and beta), sickle cell disease, cystic fibrosis, spinal muscular atrophy (SMA), Huntington's disease, BRCA1/2 breast/ovarian cancer mutations, myotonic dystrophy, fragile X syndrome, Duchenne/Becker muscular dystrophy, haemophilia A and B, and many other rare inherited conditions. Each PGT-M test requires a bespoke laboratory design specific to the family's mutation. Please consult a genetic counsellor and your fertility specialist to confirm whether your specific condition can be tested.

Question 61

Can PGT-M prevent inherited diseases?

Dr Vidhu D · Accepted Answer

PGT-M can prevent a specific known inherited disease from being passed to a child conceived through IVF. By transferring only embryos that do not carry the causative mutation (or only carrier embryos for recessive conditions, depending on preference), the condition is not transmitted. It does not prevent de novo (new) mutations or other unrelated conditions. PGT-M is one of the most powerful tools in reproductive genetics for families with serious hereditary conditions. It requires: identification of the specific causative mutation, IVF, embryo biopsy, and genotyping. Prenatal testing (NIPT or amniocentesis) is still recommended in the resulting pregnancy as a safety check.

Question 62

Can PGT-M test for thalassemia?

Dr Vidhu D · Accepted Answer

Yes — thalassemia (both alpha and beta) is one of the most common indications for PGT-M, particularly relevant in India where thalassemia carrier rates are high in certain populations (2–17% in different regions). PGT-M for thalassemia allows couples who are both carriers to conceive through IVF, have their embryos tested, and transfer only embryos that are either unaffected (normal) or carriers (who will not have the disease). The test requires prior identification of both partners' specific thalassemia mutations, a 6–8 week laboratory setup period, and a full IVF cycle. Please consult a haematologist and genetic counsellor alongside your fertility specialist.

Question 63

Can PGT-M test for SMA?

Dr Vidhu D · Accepted Answer

Yes — Spinal Muscular Atrophy (SMA) is one of the most common serious autosomal recessive conditions tested with PGT-M. SMA is caused by deletions or mutations in the SMN1 gene. With carrier rates of approximately 1 in 40–50 in the general population, both partners being carriers (and therefore a 1 in 4 chance of an affected child) is not uncommon. PGT-M for SMA involves: confirming both partners' SMN1 mutation status, laboratory test design (6–8 weeks), IVF with embryo biopsy, and transfer of unaffected or carrier embryos only. Please consult a neurologist or genetic counsellor alongside your fertility and IVF specialist.

Question 64

Can PGT-M test for BRCA mutations?

Dr Vidhu D · Accepted Answer

Yes — PGT-M for BRCA1 and BRCA2 mutations (which confer significantly elevated lifetime risk of breast and ovarian cancer) is technically available and ethically complex. It involves selecting embryos that have not inherited the BRCA mutation. Key considerations: BRCA is not a certainty of disease — it is a risk gene. Not all BRCA carriers develop cancer. The decision to use PGT-M for BRCA requires careful genetic counselling covering: the specific mutation's penetrance, the couple's values regarding testing for adult-onset conditions, and whether they would consider non-carrier embryo transfer. ESHRE 2023 considers PGT-M for BRCA ethically permissible under appropriate counselling. Please consult a genetic counsellor and oncologist.

Genetic Testing FAQs — NIPT, PGT-A, PGT-M & Amniocentesis

NIPT

Amniocentesis & Prenatal Dx

PGT-A (Embryo Chromosome)

PGT-M (Single Gene)

PGT-SR (Translocation)

Carrier Screening

Browse by Testing Category