17 weeks fetus, short nose bone?

Question
Hello doctor,
I am 37 years old this year, I am 17 weeks pregnant, my second child. I did a prenatal screening test at 13 weeks, Trisomy results 21.18.13 low risk. But at week 17, the ultrasound showed a short 3.0 nasal bone. So let me ask the 17-week fetus, is the short nose bone okay?
Truong Thi Thien Ly (1984)
Answer
Answered by Doctor Trinh Thi Thanh Huyen - Obstetrician and Gynecologist - Department of Obstetrics and Gynecology - Vinmec Hai Phong International General Hospital.
Hello friend,
With the question “Is 17 weeks pregnant with short nasal bones? ”, the doctor would like to answer as follows:
Ultrasound or Double test are both useful in screening for pregnancy. The accuracy of Double test combined with the results of ultrasound measurement of nuchal translucency for the fetus has the ability to detect fetal malformations in about 90% for Down syndrome, 5% false positive; 95% of fetuses had Edwards syndrome and Patau syndrome with 0.3% false positives. Screening results in the first trimester only assess the presence or absence of nasal bones, but it is more significant from the second trimester onwards by measuring the length of the nasal bones.
Like many other indicators, nasal bone length will also depend on many different factors such as genetics, ethnicity, or gestational age. If parents with long nasal bones will give birth to children with long nasal bones, Europeans, Americans, ... will have longer nasal bones than Asians, or the higher the gestational age, the larger the nasal bones will be.
Depending on the gestational age, the doctor will conclude that the length of the nasal bones is different, the doctor will compare that length with certain standards for each week of pregnancy to conclude that the baby's nasal bone condition is short or short. normal. There is no specific measurement of nasal bone length at this stage, but if the nasal bone length at 22 weeks gestation is greater than or equal to 4.5mm, it is normal and less than 3.5mm is short.
Thus, in your case when the gestational age is 17 weeks, measuring the length of the nose bone 3mm without any other suspicious signs, you can wait until 22 weeks for further evaluation. During pregnancy, you need to eat enough nutrients, supplement the necessary micronutrients at each appropriate stage and have regular antenatal check-ups in consultation with a specialist.
If you still have questions about the 17-week fetus with short nasal bones, you can go to the hospital of Vinmec Health System for further examination and advice. Thank you for trusting and sending questions to Vinmec. Wishing you lots of health.
Best regards!