Hiro Clinic Offers Prenatal Diagnosis
to Detect Intellectual Disabilities
During pregnancy, it is not uncommon to have anxieties and questions such as, “Is my baby healthy?” or “Should I get prenatal testing?” To address these concerns, NIPT (Non-Invasive Prenatal Testing) is gaining attention as an option.
NIPT is a test that examines the baby’s chromosomal abnormalities using the mother’s blood during pregnancy. Since it is conducted through a blood draw from the mother’s arm, it is a safe test with virtually no risk of miscarriage for either the mother or the baby.
While previously only Down syndrome could be detected, advances in testing have now made it possible to detect conditions associated with many types of intellectual and developmental disabilities.
Here, we provide a detailed explanation of the conditions that can be detected through NIPT, as well as the differences in testing details across various facilities.
Conventionally, it was said that NIPT testing was impossible before the 10th week of pregnancy. However, through joint research with the Tokyo Health Laboratories, Hiro Clinic NIPT has made it possible to conduct the test from the moment the fetal heartbeat is confirmed via ultrasound. This allows for the early screening of many prenatal conditions, not only genetic abnormalities known as trisomies 21, 18, and 13, but also intellectual and developmental disabilities (microdeletions, autosomal recessive disorders, as well as whole-chromosome partial deletions and duplications).
NIPT = Non-Invasive Prenatal Testing
What is NIPT (Non-Invasive Prenatal Testing)?
Benefits of NIPT (Non-Invasive Prenatal Testing) and the Unique Strengths of Hiro Clinic
Can Be Performed with Just a Blood Draw
NIPT requires only a sample of the mother’s blood.
Unlike amniocentesis, there is no need to insert a needle into the uterus, making the physical burden relatively light.
Early Testing Available Before the 10th Week
While NIPT is generally available from the 10th week of pregnancy onwards, Hiro Clinic NIPT, through joint research with the Tokyo Health Laboratories, allows for early testing from the moment the fetal heartbeat is confirmed via ultrasound.
High Accuracy and Unique “Positivity Score”
Compared to conventional testing, NIPT features a high detection rate for chromosomal abnormalities (approx. 99.9% sensitivity for trisomy 21). Furthermore, instead of a simple age-based probability, Hiro Clinic provides a unique “Positivity Score” derived from fetal genetic data that indicates the likelihood of a condition (degree of genetic abnormality).
Important Notes on NIPT & Support for Positive Results
Not a Definitive Diagnosis
NIPT is a screening test; therefore, a positive result does not provide a definitive diagnosis. If a positive result is obtained, a definitive diagnosis through further testing, such as amniocentesis, is required. At Hiro Clinic, we provide a subsidy of up to 200,000 yen (including tax) for amniocentesis testing costs for individuals who receive a positive result.
Hiro Clinic NIPT offers a wide variety of tests and optional plans, including our Positivity Score Report, which was developed based on data from pregnant patients who have undergone our testing in the past. Please refer to this page for more details.
Main Conditions Detected by NIPT (Non-Invasive Prenatal Testing)
NIPT primarily allows you to check for the possibility of the following chromosomal abnormalities.
Trisomy 21 (Down Syndrome)
Among the various chromosomal abnormalities, this condition has the highest frequency of resulting in live birth. It is often accompanied by moderate intellectual and developmental disabilities, and complications such as heart defects, low muscle tone, and digestive tract abnormalities may also be observed. By understanding the possibility early on, families can consider post-birth medical support systems, prepare themselves emotionally, and arrange the living environment well in advance.
<Click here for details>Trisomy 18 (Edwards Syndrome) / Trisomy 13 (Patau Syndrome)
These are chromosomal abnormalities caused by an extra third copy of chromosome 18 or 13, respectively. The prognosis is very severe, and in many cases, it leads to spontaneous miscarriage or stillbirth during pregnancy. Even if the baby is born, the condition is often accompanied by severe malformations, heart defects, and central nervous system abnormalities, and many pass away within a few days to months after birth. Information regarding these conditions serves as crucial material to support families in their decision-making and choices regarding the continuation of pregnancy.
<Click here for details>Aneuploidy of All Chromosomes (Miscarriage Screening)
In addition to the commonly known chromosomes 21, 18, and 13, it is possible to screen for abnormalities—including trisomy (one extra chromosome) and monosomy (one missing chromosome)—across all autosomes from chromosomes 1 to 22. This whole-chromosome testing plan is designed for individuals who wish to receive a more detailed and comprehensive risk assessment. In particular, whole-chromosome testing is recommended for the following individuals:
- Pregnant women who have been informed of fetal abnormalities of unknown cause
- Individuals with a history of miscarriage
- Those who desire a broader and more extensive risk assessment
- Those who wish to anticipate the likelihood of miscarriage to some extent
If an abnormality is detected, it enables a smooth transition to a definitive diagnosis via amniocentesis or to genetic counseling.
<Click here for details>All Autosome All Region Partial Deletion/Duplication & Microdeletion Syndromes (Intellectual Disability Screening)
These are cases where there is an abnormality in the “structure” of the chromosomes rather than the “number.” This refers to a state where a piece of a chromosome is missing (deletion) or extra (duplication), which frequently manifests as intellectual or developmental disabilities. At Hiro Clinic, it is possible to screen for up to 116 types of microdeletions and microduplications. Because these conditions occur independently of maternal age, this test provides meaningful insights for all pregnant individuals.
<Click here for details>Determination of Sex Chromosome Aneuploidies (Infertility Screening)
This checks for an abnormal number of sex chromosomes (X and Y chromosomes) that determine biological sex, such as Turner syndrome or Klinefelter syndrome. While clear abnormalities are often not visible immediately after birth, infertility or hormonal abnormalities frequently become apparent after adolescence or during adulthood. Early diagnosis allows for the timely preparation of appropriate treatment and support.
<Click here for details>Sex Determination
By analyzing the fetal DNA present in the mother’s blood, you can learn the sex of your baby at an early stage. In the case of twins, if a Y chromosome is detected, it indicates that one or both of the babies are boys.
<Click here for details>What NIPT Can Detect
Aneuploidy of All Chromosomes (Miscarriage Screening)
At Hiro Clinic NIPT, we inform you of chromosomal aneuploidy (numerical abnormalities), including not only trisomies—where there are three copies of a chromosome—but also monosomies and other numerical variations.
Aneuploidy of Autosomes (Chromosomes 1–22) [Miscarriage Screening]
About Whole-Chromosome Aneuploidy Testing
In addition to the commonly known aneuploidies (numerical abnormalities) of chromosomes 21, 18, and 13, Hiro Clinic NIPT allows you to screen for abnormalities across all autosomes from chromosomes 1 to 22, including trisomy (one extra chromosome) and monosomy (one missing chromosome).
This whole-chromosome testing plan is designed for individuals who wish to receive a more detailed and comprehensive risk assessment, covering abnormalities that cannot be detected by conventional basic NIPT.
We also offer single-item plans with a more targeted scope, catering to specific needs such as screening exclusively for chromosome 21 (Down syndrome).
Chromosome 21 of Particular Concern: Down Syndrome
Among various chromosomal abnormalities, Trisomy 21—commonly known as Down syndrome—is the condition that most frequently results in live birth.
- Approximately 20% of cases with a chromosome 21 abnormality at the fertilized egg stage (out of all cases with chromosomal abnormalities) proceed to live birth.
- It is often accompanied by moderate intellectual and developmental disabilities.
- Complications such as heart defects, low muscle tone, and digestive system abnormalities may also be observed.
By identifying the possibility of Down syndrome at an early stage, families can consider post-birth medical support systems, prepare themselves emotionally, and arrange the living environment well in advance.
Other Severe Chromosomal Aneuploidies: Chromosomes 18, 13, and Others
On the other hand, while Trisomy 18 (Edwards syndrome) and Trisomy 13 (Patau syndrome) are similar to Down syndrome in that they involve an extra copy of a chromosome, their prognosis is extremely severe and characterized by the following:
- In most cases, they lead to spontaneous miscarriage or stillbirth during pregnancy.
- Even if born, infants often present with severe malformations, heart defects, and central nervous system abnormalities, with many passing away within a few days to several months after birth.
- Therefore, our clinic categorizes these conditions as “miscarriage-associated chromosomal abnormalities” and views them as vital information to support families in making decisions regarding the continuation of pregnancy.
The Significance of Whole-Chromosome Testing
While conventional NIPT often focuses only on chromosomes 21, 18, and 13, in reality, a certain number of cases involve abnormalities in other chromosomes. In particular, whole-chromosome testing is recommended for the following individuals:
- Pregnant women who have been informed of fetal abnormalities of unknown cause
- Individuals with a history of miscarriage
- Those who desire a broader and more extensive risk assessment
- Those who wish to anticipate the likelihood of miscarriage to some extent
The benefit of finding an abnormality is that it enables a smooth transition to a definitive diagnosis via amniocentesis or to genetic counseling.
Determination of Sex Chromosome Aneuploidies (Infertility Screening)
About Sex Chromosome Aneuploidy (Abnormalities in the Number of X and Y Chromosomes)
Human chromosomes consist of autosomes (chromosomes 1–22) and sex chromosomes (X and Y chromosomes) that determine biological sex.
An abnormal number of these sex chromosomes is referred to as “sex chromosome aneuploidy.”
Hiro Clinic NIPT includes the following representative sex chromosome aneuploidies as targets for screening:
- Turner Syndrome (45,X): A monosomy condition where only one X chromosome is present instead of the normal pair of two.
- Klinefelter Syndrome (47,XXY, etc.): A trisomy condition where there is an extra X chromosome compared to a typical male karyotype (46,XY).
Features of Sex Chromosome Aneuploidy
Compared to autosomal aneuploidies (e.g., Down syndrome), these sex chromosome abnormalities often present with no obvious symptoms immediately after birth, and the degree of disability tends to be relatively mild.
However, infertility or hormonal abnormalities frequently become apparent during adolescence or adulthood, and growing up without realizing the condition can delay necessary treatment and support.
Recognizing the condition early and taking appropriate measures enables symptomatic management, such as hormone replacement therapy, helping to maintain a better quality of life (QOL).
Representative Sex Chromosome Disorders
| Disease Name | Chromosomal Abnormality | Main Features | Treatment & Management |
|---|---|---|---|
| Turner Syndrome | 45,X (Missing one X chromosome) | Short stature, ovarian dysfunction, delayed onset of puberty, infertility | – Growth hormone replacement therapy (from early childhood) – Estrogen replacement therapy (from adolescence) – Fertility treatment (such as egg donation) |
| Klinefelter Syndrome | 47,XXY (One extra X chromosome) | Tall stature, lack of muscle mass, incomplete secondary sexual characteristics, infertility | – Testosterone replacement therapy (from adolescence to adulthood) – Speech and learning support (depending on the case) – Fertility treatment via sperm retrieval (such as TESE) |
| Other Sex Chromosome Abnormalities (e.g., 47,XYY / 47,XXX, etc.) | One extra Y or X chromosome | May present with learning disabilities or developmental variations (significant individual differences) | – Developmental support and educational intervention as needed – Medical follow-ups (monitoring hormone levels and growth) |
Significance of Early Diagnosis
Sex chromosome aneuploidy is often overlooked at birth, and it is not uncommon for individuals to discover it for the first time as adults during fertility treatment or similar evaluations.
However, if early detection becomes possible during pregnancy through Non-Invasive Prenatal Testing (NIPT), it enables proactive measures such as:
- Starting appropriate treatment before adolescence
- Preparing academic and psychological support
- Emotional and social preparation for the family
…making such proactive measures possible.
At Hiro Clinic, we provide information during the prenatal stage to support families so they can look ahead to the future with peace of mind.
| Disease Name | Treatment Period | Treatment Method |
| Turner Syndrome | From age 3 to adolescence | Regular administration of growth hormone injections |
| From adolescence onwards | Female hormone injections | |
| Klinefelter Syndrome | By age 30 | Sperm retrieval via TESE. Performing intracytoplasmic sperm injection (ICSI) makes it possible to give birth to a healthy child; however, performing the procedure by age 30 leads to a higher success rate. |
Early diagnosis is essential to perform these treatments at an early stage.
Globally, tests to screen for sex chromosome aneuploidy are widely conducted as routine screening.
Sex Determination
We will inform you of your baby’s sex.
In the case of twins, the test determines whether a Y chromosome is present, which tells you whether at least one boy is present.
- Both are girls
- Either one or both are boys
This test analyzes fetal DNA from the mother’s blood, allowing you to learn the sex of your baby at an early stage. For twins, if a Y chromosome is detected (provided there is no aneuploidy in the fetal sex chromosomes), it indicates that one or both of the babies are boys. This test can help parents prepare and make important decisions ahead of time.
Whole-Chromosome Partial Deletion and Duplication Disorders (Intellectual Disability Screening)
Is Testing Only for Down Syndrome Enough? Why We Recommend Screening for “Intellectual Disabilities (Partial Deletions and Duplications)” That Heavily Impact Families
In prenatal diagnosis, screening for representative conditions caused by abnormalities in the “number of chromosomes”—such as Down syndrome (monosomy: one missing chromosome, trisomy: one extra chromosome)—is well known. However, that is not all. There are also numerous cases where anomalies occur in the “structure” of the chromosomes rather than the “number.”
A structural anomaly refers to a state where a piece of a chromosome is missing (deletion) or extra (duplication). Although these abnormalities may not be readily apparent at first glance, they have the potential to significantly impact development and overall health.
Partial Chromosomal Deletions and Duplications with Significant Impact on Families (Intellectual Disability Screening)
In cases of full trisomy (where an entire chromosome is duplicated), the condition often leads to severe, life-threatening complications shortly after birth.
On the other hand, individuals with partial deletions or duplications frequently live for a long period after birth, meaning families will spend many years raising and supporting them.
Consequently, long-term support systems that encompass not only medical care but also daily living assistance, specialized education, and social services become crucial. Because this has a profound, long-lasting impact on the family, receiving proper information and being able to prepare in advance is essential.
Screening for Up to 143 Types of Microdeletion and Duplication Disorders (Intellectual Disability Screening) View Details
About Disorders Caused by Microdeletions and Microduplications
In recent genetics, it has become clear that among chromosomal structural anomalies, abnormalities in extremely small regions—specifically known as “microdeletions and microduplications”—exert a major impact on a child’s development and health.
These are cases where deletions or duplications occur in incredibly small regions of 5 million base pairs (5 Mb) or less, making them notoriously difficult to detect using conventional chromosome testing (G-banding). However, even though the size is tiny, missing or extra material in a region containing crucial genes can severely affect development, intelligence, and physical functions.
Screening Available for Up to 143 Types of Microdeletions and Duplications
Hiro Clinic NIPT provides testing designed to address these minute structural abnormalities.
It is possible to screen for the presence of microdeletions and microduplications associated with up to 143 types of conditions.
These abnormal regions often contain many critical genes involved in brain development, neurological function, and organ formation, meaning that most cases are accompanied by intellectual and developmental disabilities.
In some instances, these abnormalities may not be visibly apparent immediately after birth, but developmental delays, learning difficulties, and specific behavioral traits can manifest as the child grows.
Younger Pregnant Women Also Face Risks
While the risk of numerical abnormalities—such as Down syndrome—is well known to increase primarily with advanced maternal age (35 and older), microdeletions and microduplications are unique in that they occur regardless of the mother’s age.
These structural anomalies almost always happen accidentally and at random during the very early stages of fetal chromosome formation. This means that even a young mother in her 20s has a possibility of conceiving a child with these specific abnormalities.
Therefore, rather than being an “evaluation limited to advanced maternal age” where the necessity of testing is judged purely by age, this screening provides meaningful insights for all pregnant individuals.
Results of NIPT (Non-Invasive Prenatal Testing) View Details
Results of NIPT (Non-Invasive Prenatal Testing)
Test results are reported as either “negative” or “positive.” When a result is positive for trisomy 21, 18, or 13, we provide a Positive Score Report. This score is a numerical value derived from the fetal genetic data that reflects how likely it is that the fetus has the condition. While the positive predictive value (PPV) is automatically calculated based on maternal age and gestational weeks, the positive score is a unique figure representing the degree of genetic alteration, which Hiro Clinic offers to patients. However, if the amount of fetal DNA in the sample (blood) does not meet the required threshold, or if certain medications being taken interfere with the analysis, the test cannot be completed. In such cases, a “re-blood draw” will be required.
What Does It Mean That NIPT Is a Screening Test?
A screening test is designed to detect a disease or condition in individuals who do not show any symptoms. It differs significantly from diagnostic testing in the following two ways:
1. The test itself carries no risk to the pregnancy.
2. It avoids incorrectly classifying a true positive case as negative.
These two aspects set it apart.
While a definitive diagnostic test provides a neutral and comprehensive determination, a screening test functions primarily to separate individuals who are likely positive from those who are not. Therefore, it must be safe for anyone to undergo, and anyone with even a slight possibility of being positive needs to be flagged as positive. Consequently, some cases will include borderline or very low-level positives that could arguably be classified as negative. For this reason, if an NIPT result is positive, it is essential to undergo definitive diagnosis (amniocentesis). Conversely, a negative result offers significant reassurance. Although it is not 100%, it can be considered over 99.99% accurate in ruling out the conditions tested.
Amniocentesis carries risks because it involves inserting a needle into the abdomen, but it is necessary to establish a definitive diagnosis.
No matter how high the sensitivity and specificity (accuracy) of NIPT may be, it is dangerous to rely on a single test for diagnosis. This is an absolute principle that holds true across the entire medical field, not just in prenatal screening.
Consider cancer screening as an example.
A diagnosis is only reached after performing CT scans, MRIs, and biopsies. Although these procedures carry various risks, they are conducted because the benefits outweigh those risks. The initial screening test, however, keeps that risk as close to zero as possible.
In summary, a key difference between a screening test and a definitive diagnosis is that if there is even the slightest suspicion of a positive result, the screening test flags it as positive. In screening tests, false positives are not a primary concern.
Even if a result is incorrectly flagged as positive, it is viewed as a necessary step to prompt definitive diagnostic testing, including amniocentesis.
Hiro Clinic Offers Two Types of NIPT Options.
Our clinic can perform two types of NIPT analyses. If either test returns a positive result, we report the final result as positive. Those who understand the principles outlined above will recognize why: NIPT is fundamentally a screening test. In recent years, the number of facilities offering NIPT in Japan has been increasing. However, testing plans and workflows vary by provider, making it important to research these differences in advance.
For example, many facilities report only the results for Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome), and Trisomy 13 (Patau syndrome), which are the most frequently detected conditions. In other words, they only provide a simple negative or positive result.
While individuals who receive a negative result can generally feel reassured, those who receive a positive result are often left worrying about the degree or likelihood of that positive finding.
The positive score resolves this uncertainty.
The positive score is an indicator that shows the genetic likelihood of the positive finding. A higher score means a clearer positive indication, pointing to a more pronounced genetic deviation.
A term often compared with this score is the positive predictive value (PPV). While some facilities provide this percentage, the PPV is calculated strictly from maternal age and the type of test; it does not utilize individual genetic data. It can actually be calculated before the NIPT is even performed. For instance, every 34-year-old mother testing for Down syndrome would receive the exact same PPV.
NIPT is not mandated to screen for all chromosomal disorders or congenital defects, and the scope of testing varies among laboratories.
Additionally, NIPT can determine the baby’s sex with high accuracy through sex chromosome analysis. Because it relies on genetic data rather than visual confirmation via ultrasound, errors in sex determination are rare. It is worth noting that there are cases where a fetus may appear female anatomically but possesses a Y chromosome genetically. One example is an abnormality in androgen receptors. Even if male hormones are produced, an abnormality on the receiving end prevents development as a male (since the default human anatomical form is female).
Furthermore, conditions involving missing or extra pieces of chromosomes, such as micro(partial)deletions and duplications, do not severely affect life expectancy but can impact high-order brain functions, leading to intellectual and developmental disabilities. Screening for these micro(partial)deletions and duplications makes it possible to anticipate whether a child may face intellectual or developmental challenges.
Opinions and discussions surrounding NIPT have recently been featured heavily across Japanese media, including television and newspapers. Various perspectives, centered primarily on ethical considerations, continue to be exchanged among the public and experts alike. However, NIPT is a test that not only assesses the risk of fetal chromosomal abnormalities but also provides insight into miscarriage risks early in pregnancy. It can be viewed as an important evaluation that helps mothers navigate their pregnancy safely and with greater peace of mind. Furthermore, identifying sex chromosome conditions early enables hormone therapies to begin from childhood, allowing parents to arrange a variety of supportive medical interventions for their child in advance.
At Hiro Clinic NIPT, physicians well-versed in NIPT (Non-Invasive Prenatal Testing) conduct genetic counseling, medical examinations, and screening, explaining the status of the fetus thoroughly and in easy-to-understand language. If there is anything you do not understand about NIPT, please feel free to ask us about anything.
Average Costs and Testing Plans for NIPT
While NIPT costs vary depending on the medical institution, the average price in Japan for screening only trisomies 21, 18, and 13 ranges from approximately 90,000 to 240,000 JPY (excluding tax).
At Hiro Clinic, we offer a variety of plans tailored to your specific objectives…
Workflow for NIPT (Non-Invasive Prenatal Testing) at Hiro Clinic NIPT
To minimize waiting times, Hiro Clinic NIPT operates strictly on an appointment-only basis. The testing process follows the steps outlined below:
Please note that depending on how busy the clinic is at the time of your appointment, you may still experience a short wait. We appreciate your understanding. For more details, please refer to our “Testing Guide.”
1.Online Reservation
After making a tentative booking through our reservation website, you will fill out the medical questionnaire, review the NIPT consent form, and watch an explanatory video with diagrams.
2.Clinic Visit (Consultation & Blood Draw)
During your visit, you will review the NIPT explanatory video, complete the medical questionnaire and consent form, undergo a consultation with a physician, and have your blood drawn.
3.Receiving Results
Approximately 95% of our patients receive their test results within 8 days of the blood draw (with the exception of certain specialized plans).
Additionally, the Express Delivery option is available at all Hiro Clinic NIPT branches, excluding affiliated clinics. The Express Delivery option is available for an additional fee of 44,000 JPY (including tax).
Please note that Hiro Clinic NIPT offers a medical consultation with a physician after you receive your results to discuss your NIPT findings. For details, please check “About Consultations with a Physician.”
The Uniqueness of Hiro Clinic’s NIPT (Non-Invasive Prenatal Testing)
Hiro Clinic NIPT provides proprietary testing based on a vast accumulation of data compiled from previously conducted NIPT (Non-Invasive Prenatal Testing) procedures.
By partnering with Tokyo Hygiene Laboratory, a domestic clinical laboratory in Japan, Hiro Clinic NIPT is able to swiftly deliver on the “right to know” for pregnant individuals and their families. Furthermore, in order to minimize instances where patients say, “Even though my NIPT result was negative…”, we offer a wide range of NIPT testing plans and optional services.
At Hiro Clinic, we perform screening to detect both trisomies and monosomies. Additionally, we report on disorders caused by whole-chromosome partial deletions and duplications of 5 million base pairs (5 Mb) or more.
Features of Hiro Clinic NIPT View Details
The most prominent feature is the ability to detect a broad range of disorders accompanied by intellectual and developmental disabilities.
At Hiro Clinic, our NIPT can report anomalies when a deletion or duplication of 5 million base pairs (5 Mb) or more is present. While missing or extra segments of a chromosome may not be fatal, they frequently impair the brain, which is responsible for higher-order functions. This impairment often manifests as intellectual or developmental disabilities.
The disorders detectable through this test are not limited to just a few types. Because hundreds to thousands of conditions can be covered, it is no exaggeration to say that the number of testable conditions is virtually limitless.
The brain is a highly complex organ responsible for higher-order functions such as thinking, memory, and emotion. Consequently, even a minute genetic abnormality can affect development and intellectual function to some degree.
In fact, it is well known that many children who possess missing or extra portions of chromosomes present with intellectual disabilities, developmental delays, learning difficulties, and distinct behavioral traits.
Hiro Clinic NIPT has board-certified obstetricians and gynecologists recognized by the Japan Society of Obstetrics and Gynecology. Additionally, ultrasound (echo) examinations can be performed prior to NIPT at our Omiya Ekimae and Osaka Ekimae clinics. With a comprehensive support system provided by physicians and staff well-versed in NIPT, anyone can undergo their consultation and testing with peace of mind.
Please check here for Available Clinics.
Hiro Clinic NIPT offers a choice of three Amniocentesis Support Plans (Lite, Standard, and Wide). For individuals who receive a positive test result, we provide a subsidy of up to 300,000 JPY (including tax) for amniocentesis costs, depending on the plan selected.
The Principle of NIPT (Non-Invasive Prenatal Testing)
The Principle of NIPT (Non-Invasive Prenatal Testing) View Details
The length of each gene fragment is typically between 50 to 200 bp.
“bp” (base pairs) is the unit representing the sequence count of A, G, T, and C nucleotides.
A sequencer reads the genetic sequences, and
a computer maps and analyzes exactly
where they originate from within the human genome.
By measuring and adjusting the count of nucleotide sequences present in each genomic region,
the overall distribution of genetic material is calculated.
This shows the length distribution of cell-free DNA (cfDNA) in maternal plasma. The blue line represents fetal cfDNA, and the red line represents total cfDNA.
By utilizing this difference in length, the fetal fraction (FF)—which is the proportion of fetal-derived cfDNA within the total circulating cfDNA—can be determined.
[Citation] Lo YM, Chan KC, Sun H, Chen EZ, Jiang P, Lun FM, Zheng YW, Leung TY, Lau TK, Cantor CR, Chiu RW. Maternal plasma DNA sequencing reveals the genome-wide genetic and mutational profile of the fetus. Sci Transl Med. 2010 Dec 8;2(61)
As gestational age progresses, you can see that the fetal fraction (FF) of cfDNA gradually increases.
Q&A
Frequently Asked Questions
We have compiled some frequently asked questions about NIPT. Please use them for your reference.
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QWhat is the correct pronunciation of “出生前診断” (Prenatal Diagnosis) in Japanese?
There are two main pronunciations in Japanese: “shusseimae shindan” and “shusshomae shindan.”
Both pronunciations exist as word combinations. While the standalone word “出生” is often pronounced “shussho” in general everyday speech, it is frequently pronounced “shussei” when used as a medical term. For this reason, the pronunciation “shusseimae shindan” is specifically used within the medical field. -
QWhat can be detected through NIPT (Non-Invasive Prenatal Testing)?NIPT (Non-Invasive Prenatal Testing) can identify risks for fetal chromosomal abnormalities, determine biological sex, evaluate the risk for certain hereditary conditions, and screen for specific structural abnormalities. This information helps identify conditions that could potentially impact the health of the fetus.
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QWhat types of prenatal diagnosis are available?Types of prenatal diagnosis include NIPT (Non-Invasive Prenatal Testing), ultrasound examinations, amniocentesis, and chorionic villus sampling (CVS). These evaluations are used to assess the overall health status of the fetus.
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QWhat can be discovered through Hiro Clinic’s NIPT screening?An NIPT screening uses a blood sample drawn from the mother to analyze fetal DNA for chromosomal abnormalities, such as Down syndrome, Trisomy 18 (Edwards syndrome), and Trisomy 13 (Patau syndrome).
Hiro Clinic’s NIPT screening is capable of detecting numerical abnormalities across all chromosomes, and can also determine whether partial deletions or duplications are present. -
QCan I completely rest assured if the NIPT result is negative?The “negative predictive value” delivers a very high accuracy rate of 99.9% across all maternal age groups; however, NIPT remains a non-definitive screening test designed to evaluate the risk of conditions caused by chromosomal abnormalities.
To establish a definitive diagnosis, a definitive diagnostic procedure such as amniocentesis or chorionic villus sampling (CVS) is required. -
QHow much does an NIPT screening typically cost?
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QWhat is prenatal diagnosis?Prenatal diagnosis refers to evaluations conducted during pregnancy using maternal blood, ultrasound, and other modalities to assess fetal development, check for structural abnormalities, and specifically evaluate the risk of chromosomal abnormalities.
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QAre there any risks involved in undergoing prenatal diagnosis?Non-definitive screening tests carry essentially no physical risk to the pregnancy, but definitive diagnostic tests (such as amniocentesis and chorionic villus sampling) carry small risks of miscarriage or infection. It is important to consult with your physician to select the most appropriate testing method.
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QIs it mandatory to undergo prenatal diagnosis?Prenatal diagnosis is entirely optional, and it is not a requirement for all pregnant individuals. The decision to undergo screening should be made by the pregnant person and their partner after consulting with a physician and thoroughly understanding the risks and purposes.
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QHow can the information obtained from prenatal diagnosis be utilized?The information obtained from prenatal diagnosis is valuable for understanding the fetal health status and evaluating the risk of chromosomal abnormalities. This allows families to establish delivery plans and arrange necessary medical support systems well in advance.
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QWhen is the most appropriate timing to undergo prenatal diagnosis?Generally, Non-Invasive Prenatal Testing (NIPT) can be performed from the 10th week of pregnancy onwards. Other diagnostic procedures, such as amniocentesis or chorionic villus sampling (CVS), are typically carried out around weeks 15 to 20 of pregnancy. You should determine the most suitable timing in consultation with your physician.
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QWhen can the sex of the baby be determined through prenatal screening?With NIPT, it is possible to determine the biological sex of the fetus with high accuracy from the 10th week of pregnancy onwards by analyzing fetal DNA circulating in the maternal bloodstream. Confirming the sex via ultrasound typically occurs around the 18th to 20th week of pregnancy or later.
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QWhat steps should be taken if a fetal condition is identified through prenatal diagnosis?If a fetal abnormality is suspected, your physician may suggest undergoing a definitive diagnostic procedure (such as amniocentesis). Following those results, you can evaluate your options and next steps in close consultation with your family and medical specialists.
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QIs prenatal diagnosis necessary for advanced maternal age pregnancies?Because the risk of chromosomal abnormalities increases with advanced maternal age (35 and older), prenatal diagnosis is frequently recommended. It is important to decide whether to undergo screening based on your individual risk factors and preferences.
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QIs prenatal diagnosis covered by health insurance?Generally, prenatal diagnosis is considered an elective evaluation and is not covered by public health insurance. However, exceptions may apply if there are specific medical complications or if the evaluation is conducted at certain specialized medical institutions.
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QIs it possible to discover abnormalities other than the targeted conditions during prenatal diagnosis?While the primary objective of prenatal diagnosis (especially NIPT) is to evaluate the risk of specific chromosomal abnormalities, other unexpected anomalies may occasionally be detected. In such instances, additional follow-up evaluations will be required.
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QWhat kind of medical institutions offer prenatal diagnosis?Prenatal diagnosis can be performed at obstetrics and gynecology clinics or specialized testing facilities. Since institutions offering NIPT must meet specific clinical and accreditation criteria, it is important to research providers and book your appointment in advance.
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QDoes a positive prenatal diagnosis result mean the fetus definitively has the condition?A positive result from a prenatal screening (especially NIPT) indicates a high risk for a chromosomal abnormality, but it is not a definitive diagnosis. To establish a definitive confirmation, diagnostic procedures like amniocentesis or chorionic villus sampling (CVS) are necessary.
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QPlease explain the ethical issues surrounding prenatal diagnosis.Ethical debates continue regarding prenatal diagnosis, as concerns have been raised regarding its potential connection to selective termination and eugenic philosophies. Consequently, individuals considering these screenings are encouraged to receive comprehensive counseling and make informed decisions based on their own personal values.
Videos of Hiro Clinic
Our clinic was featured in a special segment on Wake Up!
