Why is nuchal fold thick at 20 weeks?

The generally accepted upper limit for nuchal fold thickness up to 20 weeks’ gestation is 6 mm. Some authors have suggested that decreasing the cutoff to define a thick nuchal fold to 5 mm would increase the sensitivity for detection of trisomy 21.

Can increased nuchal translucency be normal?

Our study shows that an increase in the NT thickness in first trimester ultrasound screening is associated with an adverse pregnancy outcome, even when the karyotype is normal. However, in euploid pregnancies with normal second trimester ultrasound findings, a favourable outcome occurs in 74.1% of the cases.

What does increased nuchal fold mean?

The nuchal fold is a normal fold of skin seen at the back of the fetal neck during the second trimester of pregnancy. Increased thickness of the nuchal fold is a soft marker associated with multiple fetal anomalies, and is measured on a routine second trimester ultrasound.

What causes increased nuchal fold?

Euploid fetuses with increased NT may present with structural anomalies, including cardiac defects, diaphragmatic hernias, exomphalos, body stalk anomalies, and skeletal defects; certain genetic syndromes, such as congenital adrenal hyperplasia, fetal akinesia, or Noonan syndrome, have been cited as possible causes.

Should I worry about nuchal translucency screening?

What if your NT results are abnormal? If your nuchal translucency screening or any other prenatal screening results indicate that your baby may be at an increased risk of having a genetic abnormality, your practitioner will likely suggest a diagnostic test like chorionic villus sampling (CVS) or amniocentesis.

What can cause increased nuchal translucency?

Increased nuchal translucency, which is caused by the subcutaneous accumulation of fluid in the neck of a fetus, and cystic hygroma of the neck are characteristic ultrasonographic findings in fetuses with trisomies, Turner’s syndrome, and certain other chromosomal abnormalities.

Does nuchal translucency always mean Down syndrome?

Relationship between NT shape and fetal abnormalities Maymon et al. (2001) reported a notch in 62% of NT cases that showed increased NT in the first trimester and that were later diagnosed with Down syndrome. It was thus indicated that NT with a notch is a marker more closely related to Down syndrome.

What causes extra fluid behind neck in fetus?

What is a cystic hygroma? A cystic hygroma is a cyst, or a group of cysts, found mostly in the neck. They are caused by an error in the development of lymph sacs and lymph vessels as the baby develops during pregnancy. By the end of the fifth week of pregnancy, the baby’s lymphatic tissues form as lymph sacs.

What does increased NT mean?

When there is more fluid than usual, it is called “increased nuchal translucency” or “large NT”. The NT is considered large when it is 3.0 mm (about 1/8 inch) or more. This is a common finding. About 1 in every 25. babies have a large NT.

Does fetal presentation affect the measurement of nuchal skin fold thickness in second trimester?

Objective: To assess the effect of imaging angle and fetal presentation on the measurement of nuchal skin fold thickness (NFT) in the second trimester. Methods: Fetal NFT was prospectively measured in 921 women at 18-21 weeks’ gestation. The population was divided into two groups according to fetal presentation.

What is an increased (thick) nuchal fold?

What is an increased (thick) nuchal fold? The nuchal fold is a normal fold of skin at the back of a baby’s neck. This can be measured between 15 to 22 weeks in pregnancy as part of a routine prenatal ultrasound.

What is a normal nuchal fold at 16 weeks?

The SOGC (Society of Obstetricians and Gynecologists of Canada) considers a nuchal fold to be abnormal when the measurement is ≥ 5 mm at 16-18 weeks, or ≥ to 6 mm at 18-24 weeks. It is the most powerful second trimester sonographic marker for Trisomy 21 / Down syndrome.

Is nuchal fold thickness a useful ultrasound marker for trisomy 21?

Introduction The measurement of nuchal fold (NF) thickness during the second trimester is considered to be one of the most sensitive and specific isolated ultrasound marker for the identification of suspected cases of trisomy 21.