Dr. Sameer Kumar
Obstetrics and Gynecology
The following is an actual conversation between an iCliniq user and a doctor that has been reviewed and published as a Premium Q&A.
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Patient's Query
Hi doctor,
Would you please explain my chances for trisomy 21? I am a 29-years-old, and this is my first pregnancy. My NT scan result was typical (1.5 mm). I underwent the double marker test. The risk for trisomy 21 was 1:438. hCG is 3.44 MoM, and PAPP was 0.53 at 12 weeks. Is that point of concern? My anomaly scan went fine except for FL at 26mm (fifth percentile).
Hi,
Welcome to icliniq.com.
I understand your concern.
With NT (nuchal translucency) scan (the attachments are removed to protect the patient's identity) normal and NT less than 2.5 mm and your age less than 30 years, the chances of Down syndrome are low. But ideally, the double marker is less sensitive than the quadruple marker test. However, a double marker suggested risk, so a quadruple marker should have been done. If the quadruple marker showed high risk, then confirmation could have been done following amniocentesis and fetal karyotyping.
The anomaly scan appears normal, with FL (femur length) and AC (abdominal circumference) ratio normal. However, it usually does not help identify Down syndrome in utero, so one cannot be sure. Therefore, the confirmation shall be through fetal karyotyping, which can be a option for by getting the NIFTY (Non-invasive Fetal Trisomy Test)
I hope you find it helpful.
Regards.
Patient's Query
Hi doctor,
What worried me was the level of hCG 16.793 ng/mL, which is 3.44 MoM, and PAPP a 0.53 MoM. May I know about the levels? Is Down syndrome the only factor behind such high levels? At one and half months of this pregnancy, I had slight bleeding, and a scanning showed I had the miscarriage of one twin. The surviving twin is the current fetus. Does it have any correlation?
Hi,
Welcome back to icliniq.com.
I understand your concern.
Now that you have mentioned that you had a twin pregnancy earlier, which vanished with time, explains the high levels of hCG (human chorionic gonadotropin) and PAPP-A (pregnancy-associated plasma protein-A) and hence the abnormal range of risk calculation for Down syndrome. As I said earlier, one cannot just rely on these levels of the double marker as these tests are not conclusive.
Therefore, the best test to rule out any likely chances of downs in your fetus is to get the NIFTY test done, which is non-invasive and is the only remaining mode that can offer you conclusive reassurance. Your NT scan was normal, and so was the anomaly scan, so with those investigatory findings behind, the double marker needs to be reconfirmed with a quadruple. Now that it is already late for the quadruple marker, the best remains the NIFTY test.
I hope you find it helpful.
Regards.
Patient's Query
Hello doctor,
During my anomaly scan, my femur length percentile was the fifth percentile (26 mm). All other ratios are,
BPD - 41 mm.
Hc - 159 mm.
AC- 135 mm.
Femur length - 27 mm.
I followed up with another scan at 20 weeks and six days. The measurements are,
BPD - 49. 3 mm.
HC - 180.3 mm.
AC - 158.7 mm.
Femur length - 31.9 mm.
Are the ratios normal? And what percentile is my femur length again? Is there any issue with my femur length growth? Please help.
Hi,
Welcome back to icliniq.com.
I understand your concern.
We consider the FL and AC ratio rather than percentile femur length. So FL and AC ratio is 20 %, less than 24.9 %, and hence normal growth per gestation.
I hope you find it helpful.
Regards.
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Obstetrics and Gynecology
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