Patient Resources
FAQs on Nuchal scan
Who should have Nuchal scan?
Every pregnant woman should ideally have a Nuchal scan.
Can all anomalies of the fetus be excluded?
No, some organs would not have completed their development or may be too small to be seen by ultrasound. However upto 60% of abnormalities can be excluded at this point.
Is full bladder required?
A partially full bladder is preferable.
What is the use of uterine artery Doppler?
Doppler studies of uterine artery along with maternal weight, family history of hypertension, previous hypertension and blood tests will help us to find out if there is a higher risk for developing hypertension later in pregnancy. If so, starting some medications at this point may help to reduce the risk.
How long will it take to complete the scan?
Usually it takes around 20 minutes . If the fetal position is not conducive it may take more time and scan may be repeated two or more times; sometimes another visit may be required.
What to do if NT is increased?
In addition to a thorough ultrasound examination blood tests or invasive tests for excluding chromosomal abnormalities will be offered. If chromosomal problems are not detected then detailed scan at 16 weeks and 20 weeks along with fetal echo will be carried out. If they are normal growth will be monitored serially and after birth a detailed examination by a paediatrician or geneticist will be carried out.
What is done during Nuchal scan?
The number , viability and size of the fetus are checked. The structure of the fetus is checked according to a standard protocol. The fluid collection behind the neck of the fetus called Nuchal translucency is measured. Doppler studies of uterine artery is also done.
What is the importance of Nuchal translucency?
Increased NT may be associated with chromosomal abnormalities, certain structural abnormalities, genetic problems and growth restriction. However we need to take note that it may be increased in some of the normal fetuses also.
FAQs on Amniocentesis
What is amniocentesis?
Amniocentesis involves collection of a small amount of amniotic fluid from the uterus by inserting a needle through the abdomen.
Will it be painful?
There will be minimum pain like any injection which is tolerable. There is no need for local or general anaesthesia.
What tests can be done on amniotic fluid?
Amniotic fluid contains baby’s cells . They can be tested for chromosomes, genetic problems and for infection.
Any precaution to be taken after the procedure?
Heavy work to be avoided for a week. Otherwise normal activities can be resumed and normal diet can be taken.
When amniocentesis is done?
It is usually done after 16 weeks.
Any risks due to the procedure?
The risk of infection and injury to the baby is negligible as proper asepsis is maintained and procedure is done under ultrasound guidance. There may be some bleeding and cramping pain which gets better with rest.
There is a small risk of miscarriage about 0.5%.
Why it is done?
Amniocentesis is advised if your Downs screening test is positive or if there are any structural problems in the fetus or if there are any genetic diseases in the family or if fetal infection is suspected.
How long will it take to get the results?
Usually karyotyping will take about four weeks. If we need to get the results of few important chromosomes results can be obtained in a weeks time.
Rarely about 1 in 2000 samples the culture may fail and we may have to repeat the procedure again.
How it is done?
The abdomen is cleaned with antiseptic solution. Ultrasound is done to identify the position of the baby and placenta and the region for needle entry is chosen. The needle is then gently inserted through the abdomen and uterus and amniotic fluid is collected with a syringe. Throughout the procedure the needle and the baby will be monitored by ultrasound.
If the amniocentesis results are normal can we presume the baby is completely normal?
No. Amniotic fluid will be tested for chromosomes and some other specific problems. Only these can be excluded. Still there may be some structural problems or growth related problems. So routine anomaly scan and if necessary growth scans need to be done.