Detailed scan is done for detecting fetal anomaly

Wana: Salam Dr,
My friends and I have encountered a 26-year-old patient, G2P1,came for IOL in view of GDM on DC, at 40 weeks POG with a history of the first child having Edward Syndrome.

What I want to clarify from you , is it true that for her current pregnancy, she would undergo this process:

-the early pregnancy scan would identify an increase in nuchal translucency
-due to her history of having Trisomy 18 baby and increase NT detected, she was thus justified to undergo the detailed scan (detection of Choroid plexus cyst and renal pelvis dilatation) & amniocentesis in midpregnancy

Or

Having the history of trisomy 18 baby alone is enough to justify her for the detailed scan?

 Abd Halim: Edward syndrome is characterized by hypercalcemia right? With morphological features such as heart valve abnormalities.

On other that comes to mind, thus hx of Trisomy 18 increases the risk of developing Trisomy 21?

Isn't nuchal translucency indicative of Trisomy 21.

 Wana: From what ive read, nuchal translucency is not specific for Trisomy 21 only, but also indicative of Trisomy 13 & 18

 Abd Halim: Ok. Jzkl

Wana: it's true that baby with Edward syndrome will have cardiac malformations. So maksudnya masa detailed scan bole detect jugak heart defects tu sume kan?
[20/10 7:01 am] Mb Abd Halim: Not sure. What i stated above was clinical manisfestation.

 Abd Halim: We ascultate the baby. Not sure if detailed scan can find that much.

 Wana: Ok tq 👌🏻

 Dr Shaiful Ehsan: Waalaikumsalam syazwanamira,
Detailed scan is done for detecting fetal anomaly....
It is done at 18 to 22 weeks...
As at this point of time, most internal organs already WELL seen on US and fetus already show movements good enough for examining all angles of view as the fetus move...

 Nuchal traslucency is done around 11 to 13 weeks POG...to identify the nuchal thickness...
It is not specific only for Down syndrome nor for any chomosomal.anomaly...
It is still detected in gastroschisis, fetal anaemia, duodenal atresia or others...
It just tell you that there is a likelihood of having abnormal baby either struturally or chomosomally.....

 Therefore, to increase the likelihood of measuring probability of having down syndrome...
Nuchal translucencny must be done together with maternal triple test which is serum AFP, bhcg & estriol...

Nevertheles...the value combinations just tell you either it fall on the high risk or normal risk to have fetal anomaly....still not confirmative...

 In Msia, any history of having baby with IUD or fetal anomaly before is indicated to be seen by O&G team at least one....
For them to assess risk and the need for detailed scan...

If indicated eg having fetal anomaly before...detailed scan can be done...

Nevertheless, having prenatal diagnosis of having fetal anomaly noted upon scan is not indicated for abortion under malaysia regulations....

Thus eventhough detailed scan or NT or tripple test been done and show more likelihood for DS....patient is not allowed to undergone abortion as it is not indicated under Malaysia laws...

 Thus it is more of mentally preparation of the mother regarding the poor prognosis of edward & patau...which usually died upon birth....

And further long term plan of DS which is not related with mortality but morbidity and delayed development...

Dr Shaiful Ehsan: Abd halim, history of trisomy 18 wont increase the risk of having trisomy 21...

Nevertheless latest worldwide guideline (RCOG)...no specific indicator for determining risk...
But previous history of downs baby plus age is definitely a strong one...

Amniocentesis is another modalities to determine type of chromosomal.anomaly...
Can be done by Dr Anna...then send to private lab...or HKL...
Result would be available if im not mistaken in 2 weeks time...(but usually patient have to pay)

I hope I have answered all ur guys doubt...
Tq.
C u guys later...

Wana: Tq dr, it does help a whole lot! 🌟 btw, amniocentesis is optional right? Relying on the detailed scan alone is enough for the diagnosis of fetal anomaly?

Dr Shaiful Ehsan: Relying on detailed scan alone is NOT enough to identify the karyotype...

For example it can tell you ur fetus had heart anomaly but cant tell you either it is Down syndrome or not......

So to know the karyotype...amniocentesis can be advised if patient keen....
Nevertheless advantage of doing detailed scan is that preparation can be made before & during delivery....

Eg we have send patient to IJN when we detect fetal cardiac.anomaly....during that time we suspect ASD plus VSD...on the same week fetal.echo was done by cardiologist of IJN and detailed plan had been made by cardiologist to parents including cardiac standby if needed....tq...

Wana: Okayy thx a lot dr! 👍🏻👍🏻👍🏻