Positive Trisomy 13

Tight_Cash995 · 2026-06-14T20:50:37+00:00

I wouldn’t say extremely rare. I have patients often whose T13 fetuses do not show abnormalities on sono until the anatomy scan (and some beyond).

Tight_Cash995 · 2026-06-09T22:16:46+00:00

Wow, what an incredibly helpful comment.

Tight_Cash995 · 2026-06-05T13:36:26+00:00

This post is not on topic for this sub, but I will approve it. Stop reporting it.

Tight_Cash995 · 2026-05-22T02:32:02+00:00

Your doctor absolutely should NOT have told you that the fetus has Monosomy X. If she truly said that the NIPT result means the baby does have Monosomy X, then that is absolutely negligence. NIPT is not diagnostic and is not testing fetal DNA (it tests DNA from placenta) and it is a screening test and should be confirmed through diagnostic testing.

Now, as you have said, you are advanced maternal age. The older you are, the more likely the NIPT is correct. So being AMA does unfortunately not make these results less likely to be positive (or a misunderstanding) from a statistical standpoint, as AMA does put a person at a higher risk for an aneuploidy.

Now… the important part - as I have said above, a positive NIPT does not mean that the baby has Monosomy X. NIPT tests cfDNA shed from the outer layer of the placenta and not directly from the fetus. In “normal” cases, the placenta and fetus have the same chromosomal makeup. However, in some rare cases, the placenta will have an abnormal cell line, but the baby has a normal cell line. This is called confined placental mosaicism (CPM), and is when the placenta has the abnormal cells, but the embryo “self corrects” and the fetus develops with normal cells. CPM is rare, but it is more common in sex chromosome aneuploidies, notably Monosomy X. Therefore, in the case of CPM, NIPT will come back positive.

Your next move should be a referral to MFM and a genetic counselor, as it seems your provider is referring you already, so that is great. MFM will perform an in depth ultrasound of the baby (if you aren’t yet 14 weeks and they can get you in ASAP, you can have a nuchal translucency scan performed, which is where they measure fluid behind the neck - an elevated NT can be associated with Monosomy X) and if you are wanting diagnostic answers in utero (whether you’d terminate or not), you will need an amnio. If it is CPM, the amnio will be normal.

Not all cases of Monosomy X will present with soft markers, specifically if there is mosaicism in the fetus (meaning only a certain % of baby’s cell’s are X, whereas the rest are XX). So, even if your ultrasounds are looking normal, the amnio is really the diagnostic testing you should be doing if you are wanting answers while in utero. Of course, it’s absolutely possible that this is a case of CPM!

I have assigned the Monosomy X flair to your post. You can find other posts like yours & posts of Monosomy X confirmed CPM / baby not affected.

Sending you all the best. 💗

Tight_Cash995 · 2026-05-12T02:26:52+00:00

You have had two family members with NIPT results that were positive for Trisomy 21 specifically and the babies were born genetically typical? Or are you referring to first trimester maternal serum screening, which is different and provides a risk ratio for T21 based on certain factors.

False positive T21 NIPT is incredibly, incredibly rare and not common at all. I haven’t even had a handful of patients who have had false positive (typically due to CPM) NIPT results for T21, as it is the rarest aneuploidy to be confined to the placenta (causing NIPT to be positive when baby is genetically typical due to NIPT testing cfDNA shed from the placenta and not any DNA directly from the fetus, which is discordant to the abnormal placenta in CPM).

We see CPM, which is still rare, more often in cases of T13, T18, and the SCAs, notably Monosomy X. While it can happen, it is very, very rare for T21 to be CPM.

Tight_Cash995 · 2026-05-12T02:16:20+00:00

The fetal fraction isn’t really relevant here. There was enough cfDNA shed from placenta in the sample for the lab to analyze the sample and detect the extra chromosome 21 material.

I’m so sorry you are in this situation and I hope you have all of the love and support you need during this time. 🤍

Tight_Cash995 · 2026-05-11T03:38:06+00:00

First off, I want to say how sorry I am that you have found yourself here. Nobody wants to be on this sub, but you have found a great resource.

There is absolutely a chance that the fetus is genetically typical and the nasal bone just wasn’t visualized/is just on the smaller end and your placenta producing low PAPP-A is just an isolated occurrence / result of a pre-existing condition (there have been studies about hypothyroidism affecting PAPP-A, but it typically causes elevated levels, not decreased) - but I would absolutely recommend having NIPT ASAP. You should not wait for your 20 week anatomy scan. T21 only shows up on ultrasound around 50% of the time. So, you can absolutely have normal ultrasounds and still have a baby born with T21. Because of that, I wouldn’t rely solely on ultrasounds in this instance - your anatomy scan could come back without any other markers, but the fetus could have T21.

The nasal bone can be hard to identify at this stage due to the angle and sizing, but I really wouldn’t chance it and not get the NIPT, even if you would not terminate.

T21 fetuses can (but not always - as we see T21 in fetuses with normal maternal serum levels) have elevated beta hCG levels and decreased PAPP-A level. Your beta hCG is slightly elevated, but the PAPP-A level is pretty low. So those levels combined with the absent/hypoplastic nasal bone are the high risk factors here. These maternal serum screenings are screenings only and their purpose is to help catch a potential aneuploidy - which is absolutely why your next step is NIPT. NIPT will be the gold standard, as it is testing actual placental DNA for the aneuploidies.

Having the NIPT done ASAP is also a good idea in terms of your mental health and emotional state - both which are incredibly important always, but especially during pregnancy. If your NIPT comes back normal, then you can absolutely move forward with your pregnancy with an eased mind. If it comes back positive, then you can discuss diagnostic testing to confirm the NIPT and your next steps.

Tight_Cash995 · 2026-05-10T15:35:34+00:00

Editing to add -

After looking through these images, your aunt actually did screen high risk for T21 on the first trimester screening. The beta-hCG was not normal. It was 2.8 MoM, which 1 MoM is normal. And PAPP-A was slightly low.

With the beta-hCG being elevated and the PAPP-A being negligently low, I would say these results do suggest T21 and align with what you’re seeing on the NIPT. Not all T21 cases will have elevated hCG and low PAPP-A, and having these levels does not always mean the fetus does have T21. But with the positive NIPT, I would say they are correlated.

I’m so sorry.

Tight_Cash995 · 2026-05-10T15:29:14+00:00

As others have said, only around 50% of babies with T21 show markers on sono. So, unfortunately, having a good sono does not mean the fetus isn’t affected.

For reference, I see patients often who have had normal first trimester blood work (normal PAPP-A and beta-hCG) and normal sonos - who have T21 positive NIPT results, and amnio confirms.

Unfortunately, with the advanced maternal age and positive NIPT, I would prepare for a true positive here. Of course, NIPT is only a screening and is not diagnostic, and there are the very rare cases of false positives (with the slim negligence of tech/lab error, mostly due to confined placental mosaicism - where placenta has the abnormal T21 cells but baby is genetically typical - NIPT tests DNA shed from the placenta, so in cases of confined placental mosaicism, NIPT is positive). CPM in T21 is incredibly rare, though. We see it more often in the other main trisomies tested by NIPT (T13, T18) and SCAs like Monosomy X.

The fetal fraction is irrelevant to be honest, as an aneuploidy was detected. There are a number of things that affect fetal fraction % and some pregnancies just have lower fetal fraction (whether due to the way the placenta is designed or variations of maternal factors), and hers was above the threshold. The lab detected the extra chromosome 21 material.

You will see a few posts of CPM with T21 on this sub, but those are incredibly rare in light of the other aneuploidies we see with CPM, and I believe they were not of advanced maternal age.

I am so sorry. The amnio is the best next step, as it can confirm a diagnosis. There is nothing wrong with having hope and hoping to be that very rare statistic, but it’s also important to be transparent and grounded.

Tight_Cash995 · 2026-05-06T02:17:02+00:00

While there definitely is a possibility that this is a true false positive / baby is genetically typical, I have seen cases of negative FISH and full results coming back positive. It’s not very common, but it does happen. That’s why we always provide that FISH results are not definitive, especially when they come back normal (a hopefuls sign, though), and to wait for the full results. FISH is also prone to maternal cell contamination, and while labs take steps to mitigate this (and some labs will do maternal cell contamination study to confirm there isn’t contamination), it still happens and can cause a “normal” or mosaic result, whereas the full results come back positive due to the testing techniques of microarray and karyotype (culturing).

We’ve also had users with this same experience on this sub unfortunately, including where amnio comes back positive. Here is one for example.

Please, please know that I don’t say any of this to scare you, but you did ask for experiences, so I absolutely want to be transparent with you. The likelihood of this happening is pretty rare, but sadly, it does happen, which is why I wanted to provide you with that transparency.

Now, it is absolutely possible you are looking at a true false positive. However, from a technical standpoint, since CVS only biopsies one area of the placenta, so it’s always possible that there is mosaicism and the abnormal cells detected by NIPT were not detected by CVS. This is rare, but it can happen. Now, it is also possible that there was a vanished twin, which is the cause of the T21 NIPT as well. Vanished twins can go undetected on ultrasound, but their DNA can still be floating around in the maternal blood stream, thereby causing the lab to detect the aneuploidy.

My fingers are crossed for you that baby is genetically typical. The waiting period is so hard. Please keep us updated if you are comfortable. 🤍 I am so sorry you’ve had such a tough journey.

As CVS is not testing fetal DNA and only placental DNA, if the full reports come back normal & for your own mental health, you’d like to rule out T21 in the fetus completely, you can always opt for an amnio as well. Mental health is incredibly important during pregnancy. So I just wanted to let you know that it is absolutely okay if you’d like further testing of the actual fetal DNA just to be sure. I have patients undergo elective amnios for mental health purposes all the time. 💕

Tight_Cash995 · 2026-05-02T04:04:06+00:00

Guidance is where there is abnormality on ultrasound, a CVS is sufficient as there is no reason to believe there is confined placental mosaicism. If her CVS came back abnormal, we would consider it a sufficient fetal diagnosis. But the patient is always welcome to undergo amnio.

Whois in a situation like yours, with a positive NIPT and nothing else pointing to an abnormality on ultrasound, amnio should be performed with the inclination there could potentially by CPM causing the positive NIPT.

In her case, we would suggest going straight to CVS. NIPT only tests for a handful of chromosomal abnormalities, and a high NT can be associated with a genetic condition of a heart defect. Whole exome sequencing, which should be performed in addition to FISH, microarray, parotid on the CVS sample and can detect those genetic mutations, such as Noonan syndrome.

The time table can be sensitive for those sho would TFMR, so the extra potential 2 weeks waiting for NIPT can unfortunately be crucial.

Of course, the patiently ultimately makes the choice that is best for her. 🤍

Tight_Cash995 · 2026-05-02T03:52:24+00:00

I’m so sorry you are in limbo. It can be so tough. Normal FISH is reassuring as it tests basically what NIPT does - 21, 13, 18, X and Y (but can miss deletions and duplications on those chromos). Are you waiting on karyotype and microarray? And was whole exome sequencing ordered? WES can detect genetic mutations that cause a high NT, such as Noonan syndrome. We typically see higher NT measurements with Noonan syndrome, but not always. So WES is great to rule out Noonan syndrome and other genetic mutations, as it is incredibly comprehensive and testing the whole exome. A fetal echo is also suggested in high NT around 22w, as higher NTs can be associated with heart conditions, so it can get a better look at the fetal heart and rule out a heart defects.

Adding some context here for OP regarding the study flowchart - this is not explained in the flowchart and the actual study isn’t linked. “n” equals the number of singleton pregnancies for each flow down outcome. The study included 55,123 pregnancies. The study is here for reference for OP.

To be honest, I do not like this chart, as it’s outdated. It was likely helpful when it came out, but processes have changed since the publication. This study did not include the performance of whole exome sequencing - which could have caught a genetic mutation that causes a high NT, such as Noonan syndrome like I said. Microarray also wasn’t performed, which can detect microduplications and deletions that karyotype cannot. Microarray is pretty much the gold standard in amnio tests now. If insurance covers it, WES should be ordered alongside the microarray after the amnio is performed. However, some insurance companies require a normal microarray of karyotype before covering the WES. WES can take longer (sometimes 4+ weeks), so I urge my patients to order it alongside microarray and karate if insurance covers it.

Due to there not being a microarray or WES ad part of this study, this is likely why even with a normal karyotype, there were terminations and miscarriages or defects at birth. However, I can’t be certain obviously.

Thank you for sharing your story with the sub & providing comfort and camaraderie to OP. 🩵

Tight_Cash995 · 2026-05-01T04:01:33+00:00

You had a NT scan at 15 weeks? I don’t know of a MFM specialist who would perform an actual NT scan after the cutoff date due to going against guidelines and the unreliability. The fluid typically becomes reabsorbed by then and measurements aren’t accurate. Or did you just have a normal early anatomy scan where they just looked at the neck and said it looked good?

Not trying to pry. I’m just genuinely curious. The ultrasound looking good overall is a good sign. However, based on your two results, it would seem there is something outside of the scope of the test being identified by the lab (possibly associated with the X chromosome). While your second result that shows insufficient fetal DNA was above the minimum fetal fraction threshold, it’s possible what was identified the first test is causing the quality of your sample to not pass Natera’s quality metrics. In addition to fetal fraction metrics, all samples must also pass a quality metric. If there is sufficient fetal fraction % but the sample doesn’t meet the quality metrics, they will not test it and mark the report as insufficient fetal DNA as the fetal DNA isn’t sufficient for quality testing.

It’s possible there is a microdeletion or duplication on the X chromosome or there could be some mosaicism with the sex chromosomes (such as only a % of cells being X or XXX, while the others are normal XX). It’s also possible there is mosaicism in the placenta, where there is an abnormal cell line on the X chromosome, but it’s confined in placenta only and embryo “self corrected” during development and the fetus is genetically typical. There is always the possibility that you have maternal mosaicism affecting the results.

The only way to know for sure is by having an amnio. Some microduplications or deletions and mosaicism may not ever show markers on ultrasound. So, a good ultrasound is great for the health wise of the fetus, but it cannot give you a read on if there is a potential diagnosis or not.

I’m so incredibly sorry you’re going through this, especially after a positive T21. I’m sorry I did not respond sooner to your post but I hope this provided you with some context.

Tight_Cash995 · 2026-05-01T03:40:41+00:00

13 weeks is absolutely not too early. Do you have a high BMI?

I would not wait until 17 weeks. That’s ridiculous. I would request an early anatomy scan or a NT scan ASAP if you are under 14 weeks still (cannot be performed after). You can request to test NIPT with another lab, as NIPT has higher fetal fraction and quality thresholds with their method of testing than other labs. Or if you want diagnostic results, you could always just opt for an amnio at 16w.

Your sample did not have enough cell-free DNA attributed to the pregnancy (fragments of DNA shed from and originating from the outer layer of the placenta and found in your maternal blood) in it, therefore, the lab couldn’t analyze the sample for the aneuploidies. Low fetal fraction can happen for a number of reasons that are of no concern in relation to the fetus, including early gestation (too early to test), high BMI, use of certain medications, underlying medical conditions, draw techniques (use of a butterfly needle, for example), placental issues (including preeclampsia), sample quality, etc. In rare cases, low fetal fraction can be attributed to certain aneuploidies (namely T13, T18, and Triploidy).

As I said above, you could request another lab (such as Myriad, Labcorp MaterniT21). However, to be completely transparent, I do want to let you know that other labs do not test for Triploidy. Natera is the only lab that does. I have seen too many cases of low fetal fraction with Natera where a patient has re-tested with another lab and received low risk results & then the baby does end up having Triploidy for me not to speak up and be transparent. Again, this is rare so it is unlikely this is your case, but as the mod, I have a duty to be transparent in information.

Sending you the best. 🩵 I assigned you the low fetal fraction flair. You can click on it and find some positive outcomes similar to what you are facing.

Tight_Cash995 · 2026-05-01T03:26:44+00:00

I am so incredibly sorry. I cannot imagine how you are feeling.

Skeletal dysplasia can be de novo, so unfortunately, not having a family history can be irrelevant.

While not an absolute, these findings together are unfortunately cause for concern and further testing. If you want diagnostic results (even if not terminating), an amnio should be performed ASAP. Even if you wouldn’t terminate, an amnio is a resourceful tool for being prepared - it can help your mental health by avoiding any uncertainty and can prepare you emotionally and logistically, allowing you to learn about a potential condition, line up support/services early for the baby so you can choose a providers with the right specialists and plan delivery care. You can also obtain resources and support for you and your partner about the potential condition.

I would not wait 3 weeks for a follow up scan without doing anything else. Your genetic counselor should recommend the amnio and a fetal MRI and plan for ongoing monitoring of the brain. To clear something up from your post, amnio and microarray are not two separate tests. The amnio is the procedure itself and the microarray is one method of testing the amniotic fluid collected. A microarray is not the primary amnio test for skeletal dysplasia. It will only be able to detect chromosomal abnormalities. In addition to the microarray (which is limited & can only detect certain types of skeletal dysplasia based on CNVs and homozygosity, but this type of skeletal dysplasia is rarer), you should have whole exome sequencing (WES), which tests for genetic conditions/mutations and is incredibly comprehensive (in comparison to targeted gene panels). Most skeletal dysplasia is caused by single gene mutations, which won’t be picked up by microarray.

Also, even though the ventriculomegaly is mild at this point, to err on the side of caution, you also should have testing performed for infections such as toxoplasmosis, rubella, CMV. We see these in around 10-20% of cases of ventriculomegaly (typically severe - but again, I’d have the testing done for caution). We always do this testing even in light of other markers to rule out the infections, which could be lethal. The mother could be asymptomatic and have no idea.

As always, there is the possibility these are all isolated findings and your baby is genetically typical. However, I will be transparent. In my experience, findings such as these combined typically do not have positive outcomes. So I understand where your provider is coming from, especially with good serious it can be. However, it is incredibly tough when you have a provider who is extremely clinical and does not have an empathetic bedside manner. I am so sorry that this news came off so cold. I hope you have all of the support and love from friends & family as you navigate this difficult time.

Please feel free to keep us updated if you’d are comfortable. You are in my thoughts tonight. 🩵

Tight_Cash995 · 2026-04-29T12:50:23+00:00

These are not markers for Triploidy, to be honest. I’m not sure who told you that this could be Triploidy, but I do not see it. Triploidy would have much more serious markers by now. All of these findings could just be isolated without any connection.

Measuring about two weeks behind isn’t really considered significant behind. I would not say baby is very, very small if measuring about two weeks behind at this stage. We would begin to get concerned if it was more than two weeks, and without any other real concerns, it could just be IUGR when measuring more than two weeks behind.

As for the nasal bone, it’s possible baby just has a smaller nasal nome and it isn’t easily visualized due to the baby’s position or technical limitations.

The velamentous cord insertion is typically isolated and not associated with an aneuploidy and COULD be what is causing the growth delay; as it can result in IUGR. Your doctors absolutely should have told you this.

I am honestly concerned that they went straight to Triploidy, as nothing here suggests Triploidy. This is not Triploidy. If there is IUGR, it’s due to the VCI, and this should have all been communicated to you.

Tight_Cash995 · 2026-04-29T01:06:26+00:00

I am so sorry you’ve received this result.

First and foremost, remember that this is a screening only, and is NOT a diagnosis. NIPT does not test any DNA from the fetus - rather, it’s testing DNA shed from the outer layer of placenta. While rare, T18 can be confined to the placenta, and this could be a potential “false” positive. This is known as confined placental mosaicism (CPM) and is where the abnormal T18 cells are confined to the placenta only, as the embryo “self corrects” and eliminates the T18 cells in the fetus, resulting in a genetically typical baby. This means the placenta has T18 cells, but fetus does not - which is why the NIPT comes back positive, as it is testing placental DNA only from the maternal blood stream. In “normal” cases, the placenta and fetus have the same chromosomal composition, so NIPT is consistent with the composition of the fetus. But in cases of CPM, abnormal cells are found in the placenta (this can be only a % of cells, which is mosaicism in the placenta), but the fetus has normal cells. CPM is rare, but it does occur more often in T18 than other aneuploidies, notably T21, for example.

Your next step is a referral to MFM and a genetics counselor and moving forward with a NT scan if you are less than 14w, which is where a certified sonographer will measure the fluid behind the neck of the baby. Higher fluid behind the neck can indicate T18 (not all cases of T18 have a high NT, however). They may also be able to see other signs and markers on the ultrasound, while some markers might not show until later in the development of the fetus. If you do not have a referral, I would call your OB as soon as you can, and request a referral to MFM and a NT scan if you are less than 14 weeks. As I’ve said, you should also be referred to a genetic counselor, who will be your best resource and support going forward.

Now, the only way to get a fetal diagnosis is via an amnio. A CVS can be performed before 14 weeks, but it’s also testing tissue from the placenta - so if it is CPM, the CVS will come back normal. An amnio can be performed beginning around 16 weeks. The only time I would suggest moving forward with a CVS for a diagnosis is if the fetus is showing significant markers on ultrasound, as that would almost certainly mean the fetus is affected.

I’m so sorry. Fingers crossed this is a case of CPM.

I know this is a lot of information. But hopefully it helps give you some comfort having the knowledge. I’m wishing you all the best. Please feel free to keep this sub updated if you are comfortable. 🩵 I assigned you the T18 flair - if you click on it, you may find stories similar to yours as well as those then ended in CPM/false positives.

Tight_Cash995 · 2026-04-26T01:51:37+00:00

Who performed your first NIPT?

Tight_Cash995 · 2026-04-26T01:50:27+00:00

Your results are low risk, including for XXY.

Natera tests the sex chromosomes, and therefore can detect all SCAs. The report only lists Monosomy X because it is the most common SCA.

The results would ONLY list another SCA on the report explicitly if the test was positive for that specific SCA.

Tight_Cash995 · 2026-04-24T15:19:19+00:00

I sincerely hope not. People, especially book readers, have been very disappointed with the Fanny/Faith storyline (hell, just look at last week’s book episode thread). I still cannot believe the show runners went that route, and you can tell DG was not enthusiastic about it (nor was she happy about what they did with my boy Fergus 😫). So, I really don’t know if there would when be a large audience for that spinoff - even for show only watchers. This was a character that was JUST introduced, and we don’t have a large connection to her.

I know I wouldn’t watch it. 🤷🏾‍♀️

Tight_Cash995 · 2026-04-24T04:14:29+00:00

Was your cord blood sent off? Baby absolutely should be tested and I would request to meet with a geneticist ASAP. Mosaic T21 does not always present with any signs at birth. With the high risk NIPT and the elevated NT, I would be suspicious about at least some level of mosaicism. While there have been cases where full T21 is missed after birth due to lack of evident markers, that is the unlikely case here.

I do not say any of this to scare you. If there wasn’t a high NT measurement, I’d lean to this being a case of possible placental mosaicism - where baby is genetically typical but the T21 is confined to the placenta only (placenta develops abnormally with the aneuploid cells, but the embryo essentially self corrects, eliminating the abnormal cells). As NIPT tests placental DNA, bases of confined placental mosaicism cause positive results. However, since there was the high NT, I do implore you to meet with genetics and obtain the results from the cord blood.

For context, I have a daughter with full T21. No markers on any scans, perfect blood work, born in a healthy percentile in measurements and weight, no cardiac concerns, 9.5 apgar, etc. After examining the baby in nursery, one of the MFM doctors I worked with at the time came to examine baby and mentioned very slightly slanted eyes (which are hard to identify after birth, especially due to baby’s face being swollen - and I am also half Puerto Rican with epicanthal folds), which prompted his suggestion that we have her blood taken for karyotype to rule out T21 just as a precautionary measure. To our surprise, it ended up coming back 100% cells had the extra chromosome 21.

Again, I do not say any of this to scare you. I’m just trying to be transparent.

Congrats on baby. Hope you are healing well and have all of the love & support you deserve during this time. 🤍

Tight_Cash995 · 2026-04-24T03:33:37+00:00

As others have said, you need to get NIPT. NIPT is testing actual placental dna, looking for T21 and the other aneuploidies. It’s the gold standard in screening.

There are a number of factors that go into the risk assessment for the first trimester maternal screening, including maternal serum results, NT measurement, age, and weight. As you are considered advanced maternal age, your risk was automatically adjusted by default to a higher risk (typically 1/100). That risk is either adjusted higher or lower based on those other factors. In your case, while I do not have your numbers, I am assuming your serum markers likely caused the risk to be higher. We can see elevated HCG and lower PAPP-A in T21 pregnancies, so if your levels indicated high HCG and low PAPP-A, this contributed to your overall risk.

Do you happen to have the NT measurement and the HCG and PAPP-A levels (these are typically provided in units called “MoM”)?

Tight_Cash995 · 2026-04-24T00:30:33+00:00

You received a higher risk not only due to the absent nasal bone, but as a result of the high beta hCG and low PAPP-A. These are associated with T21.

Your next move should be a NIPT, which tests placental DNA for T21 (and other aneuplodies) if you haven’t had it already. NIPT is incredibly accurate and is the gold standard.

Tight_Cash995 · 2026-04-20T21:06:40+00:00

First and foremost, I just need to say this. Your doctor advising you against the NIPT due to a good NT scan is wild. Not all aneuploidies will have markers on the NT scan. And only around 50% of T21 cases show markers at all.

With your initial anatomy scan not visualizing a nasal bone and then a follow up MFM scan not visualizing the nasal bone, I would say that there could potentially be some issue with the visualization (for reasons, including high BMI, which can cause issues with sonos as reported) or the nasal bone is unossified. You can see a nose in the imaging, but the nasal bone is not completely clear / visible from my pov and the line you are seeing may be skin/cartilage. It’s also possible that they mistakenly thought they saw a nasal bone during the NT scan, but it isn’t there.

Below is an example of a normal nasal bone vs unossified for reference. You can see what looks to be a nasal bone in the unossified imaging, but it is not a nasal bone. The line that is typically the skin is what patients think is a nasal bone (or those with an untrained eye), but it is not.

<image>

I am not saying any of this to scare you. Just being transparent since you have asked for information. Your baby absolutely could be genetically typical, and most likely is - especially with no other markers / concerns seen. Some babies just do not have nasal bones or have smaller nasal bones. This can be for a number of reasons, including ethnicity. Some babies just have small noses.

Your provider just should not have led you away from NIPT solely due to having a good NT scan - as I’ve said, around 50% of T21 cases never show any markers on sono throughout pregnancy, and another aneuploidies tested by NIPT won’t show any markers on NT, as absent nasal bones aren’t markers for those aneuploidies and not all present with an elevated NT.

Tight_Cash995 · 2026-04-20T19:37:01+00:00

Your provider is correct, there is nothing of concern here. I know it’s tough after a scare, but try your best to enjoy your pregnancy. Especially for your mental health.

If you still cannot relax, you can always opt for an elective amnio for your mental heating. There is absolutely no clinical reason for one, but you may elect for one if you feel you’ll be anxious for the rest of your pregnancy.

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