Trisomy 13 Experience (in limbo)

I am a very long time lurker here making this post in the hours after my amniocentesis at 18+0 after positive NIPT for trisomy 13.

TLDR: positive Maternit21 AND Natera for T13. Scans normal at 12 and 16 weeks. Amnio pushed back to 18 weeks due to no safe pocket. Now waiting for results.

Below is a very detailed post for those like me who need ALL the information. It was therapeutic to get this all off my chest. I am so incredibly grateful for the creator/mods/regulars of this sub. Without this sub, I would have felt completely isolated and alone. You are angels.

Around 9+3, I did Maternit21 which came back just 5 days later positive for trisomy 13 with a "high mosaic ratio which may affect the PPV" which was quoted at 10%. Male fetus. Everything else low risk. My OB was wise enough to call the MFM genetic counselor before talking to me, so she related the possibility of CPM to me right away, which I am very grateful for after reading the many terrible experiences of other women on this thread. The results from LabCorp/Maternit21 referenced one single article by Rafalko et al. As a primary care doctor myself, I immediately jumped straight into the data reading every peer reviewed article out there. I learned the PPV of 10% was based only on my age 31 (and hence my age based risk of trisomy 13), gestational age of the pregnancy (PPV goes down the further along you are because the risk of spontaneous miscarriage is high with T13), and the specificity of the test (99.7%). LabCorp is the only lab I know of that reports a mosaic ratio (low, high, or non-mosaic). In the Rafalko article, the PPV (which did not take into account maternal age) was lowest for low mosaic ratio less than 10%, in the 60% range for high mosaic and almost 100% for non-mosaic. LabCorp does not report the exact mosaic ratio of your test, only puts you into one of these groups. I don't know if I am closer to the low mosaic range or the non-mosaic range. The major flaw with this study and with a lot of studies regarding T13/18 is that they dont have follow up for all the positive NIPT results. In fact, they only had results for 20% of the T13 NIPT samples in the Rafalko study. That seems rather small and it seems plausible that providers are more likely to report results on true positives than false positives, but I have no data to confirm that. Personally, as a physician, I would feel really uncomfortable reporting this data to a patient based on one study that only captures 20% of the picture. I think this a similar story to natera's 68/100 PPV. Very frustrating.

Anyways, after my NIPT results I went to the darkest of places mentally. This pregnancy is a very wanted miracle pregnancy that came after 2 years of secondary infertility for male factor and DOR (my healthy daughter is 4yo and was conceived naturally after 4 months TTC). Before this pregnancy, I went through 3 failed IUIs, 1 egg retrieval and 2 failed FETs. For reference, my 3 blasts from the egg retrieval were all PGT normal (I still have 1 frozen). After the second FET, I did a mock cycle with endometrial biopsy that came back normal. While waiting to cycle again for the 3rd FET, we spontaneously conceived. We were absolutely overjoyed. I had some spotting between week 6-7 and similar to others with infertility and/or loss, I had been constantly anxious feeling like something can't possibly go right for me. Because of this, I actually started therapy before I even got my NIPT results. I think that may have been the smartest move I have ever made. I am so blessed to be able to afford access to a good mental health provider and I wish everyone had this resource easily available. Alas, that is not the case. I do wish I would have waited until closer to the NT scan to do the NIPT since I have learned there is really nothing to take action on based on NIPT alone. It would have allowed me 2 more weeks of ignorant bliss and would not have slowed down my diagnostic timeline.

Fast forward through the weeks of agony which I have come to describe as the "marathon of torture," I got my NT ultrasound and basic anatomical survey at 11+6 with our local MFM. He was measuring 2 days ahead and the highest NT measurement of the three was 1.1mm (the others were in the 0.9mm range). The MFM could also make out a 3v cord, brain with proper separation of the lobes, 4 chamber heart and normal fetal heart rate around 160. I left this scan feeling slightly better. I slugged through 4 more weeks of the marathon of torture until my early anatomy scan at 16+0 where everything continued to look "normal". Still measuring ahead 2-3 days with HR in 150s. She confirmed all of the things from the NT scan and additionally got a good view of the lips which did not show any clefting. Too early to tell cleft palate. MFM again performed the scan herself. She noted a very anterior placenta and no great window for the amnio. She probably would have done it, but I'll admit, I chickened out and kinda convinced her not to do it. She decided to have me come back 2 weeks later to check the window again. I requested to repeat the NIPT again given the normal scans on a hail mary that the first result was a false positive testing error rather than CPM. If negative, I would probably have skipped the amnio unless something new showed up on scans. Unfortunately, the repeat test which I did with Natera came back T13 68/100 risk. This sent me into another spiral even though I was expecting this result. I am still on the fence about whether repeating the NIPT was harmful or beneficial. On one hand, it makes me feel more confident in my choice to proceed with amniocentesis, but it really shook me up again in a way that I didn't anticipate. I also still haven't gotten the bill for either NIPT, so that's another factor to consider.

Today, 18+0, I went back for the amniocentesis and she was able to find a very very small safe window and do the amniocentesis. It was physically very easy maybe 1-2 out of 10 on the pain scale. Mentally, it was a lot harder than I expected. The baby was also very close to the needle, and I am sure he touched it at some point. I am reading that the needle is maybe retractable and leaves a flexible catheter in place after accessing the amniotic fluid, but I was too shaken up to question the MFM on this. She didn't seem concerned. She pulled about 20mL of urine colored fluid and showed me the baby's heart after the procedure. She didn't do any look at fetal anatomy again today (I didn't expect her to). At the recommendation of the GC, I skipped the FISH. I decided I wouldn't act on the FISH result and I didn't want the risk of being falsely reassured. So now we wait 1-2 weeks for the karyotype and 2-4 weeks for microarray.

I didn't anticipate how much anxiety I would be having about the risk of complications after the amniocentesis. I know it is considered a safe procedure, but of course I have read all the nightmare stories on here. I am also, of course, having anxiety about the results of the testing. A part of me just wanted to stay in my little cautiously optimistic bubble of normal scans. Now I am forced to face results. It's a weird feeling that I really didn't anticipate having.

I will try to update with results when they come, though I am sure I will have a hard time doing so if the results are not favorable.

All in all, I am incredibly inspired by the brave women on this thread. You all have helped me keep one nostril above water and inspired me to write my story in case it resonates with someone else in my shoes in the future. Thank you for reading and all my love to those who have found themselves needing this subreddit. For anyone who has questions, I am happy to chat more.