The Ratio of Prenasal Thickness (PT) to Nuchal Fold Thickness (NFT) in Fetal Screening Ultrasonography at Second Trimester of Pregnancy and the Relationship with Maternal Age, Gestational Age and Fetal Sex

Document Type : Original Article

Authors

1 Pediatrician and Neonatologist, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

2 Assistant professor, Department of Radiology, Faculty of Medicine, Islamic Azad University, Mashhad Brabch, Mashhad, Iran.

Abstract

Introduction: Regarding to the importance of the main role of ultrasonography in screening of chromosomal disorders, the present study was performed with aim to evaluate the relationship between NFT and PT in fetuses of second trimester of pregnancy; if these two ultrasonographic markers are correlated, PT can be used in fetuses in which NFT cannot be measured due to fetal position in the uterine.
Methods: In this descriptive-analytical and cross-sectional study, 500 pregnant women at second trimester of pregnancy underwent routine ultrasound scan of anomalies. First, pregnancy ultrasound along with determination of gestational age and general pregnancy information, as well as scan of anomalies including all fetal organs were done and fetal sex, maternal age and gestational age were recorded. Data analysis was done using SPSS (version 22) and Statistica (version 10) statistical software. P<0.05 was considered statistically significant.
Results: The mean gestational age was 19 weeks and mean maternal age was 30.26 years. The mean of PT in pregnant women with gestational age of less than 19 weeks was 1.8±0.212 mm, and in pregnant women with gestational age of ≥19 weeks was 5.6±0.161 mm (p<0,001). The mean of NFT in pregnant women with gestational age of less than 19 weeks was 2.9 ±0.194 mm, and in pregnant women with gestational age of ≥19 weeks was 5.9±0.187 mm (p<0,001). The mean of PT according to maternal age was 4.4±0.32 mm, which increased from 2.7 mm under 20 years to 5.65 mm over 40 years (p<0.001). Also, the mean of NFT according to maternal age was 4.2±0.211 mm, which increased from 3.2 mm under 20 years to 5.3 mm over 40 years (p<0.001), so there was a significant relationship between PT and NFT with gestational age and maternal age; Thus, both increased with increasing gestational age and maternal age (p<0.001). PT/NFT ratio was stable according to gestational age (p=0.205), maternal age (p=0.111) and fetal gender (p=0.752). No significant relationship was observed between maternal age, gestational age and fetal gender with PT/NFT ratio (p>0.05).
Conclusion: It was found that NFT and PT as the ultrasonographic markers of aneuploidies are correlated with each other. It can be concluded that PT can be used in cases which NFT cannot be measured due to fetal position in the uterine.

Keywords

References

  1. Beirami M. Numerical and structural chromosome aberrations in aborted fetuses with using fetal cell culture and staining with GTG Banding method. Journal of Arak University of Medical Sciences 2009; 12(3):92-100.
  2. Tolmie JL, MacFayden U. Clinical genetics of common autosomal trisomies. Principles and Practice of Medical Genetics. 5nd Churchill Livingstone-Elsevier, Philadelphia 2007: 1015-26.
  3. Yeo L, Vintzileos A. The Second Trimester Genetic Sonogram. In: Callen P. Ultrasonography in obstetrics and gynecology. 5th Philadelphia: Judith Feltcher; 2008. P. 70-103.
  4. Coates TL, McGahan JP, Fetal Face. In: McGahan JP, Goldberge BB. Diagnostic Ultrasound. 2nd New York: Informa Healthcare USA; 2008. P. 1181-2.
  5. Eiben B, Glaubitz R. First-trimester screening: an overview. Journal of Histochemistry & Cytochemistry 2005; 53(3):281-3.
  6. Ls P. The effects of change in maternal age distribution upon the medicine of mongolism. J Ment Defic Res 2009; 11(1):54-7.
  7. Farndon PA, Kilby MD. Genetics, risks and genetics counseling. In: James DK, Steer PJ, Weiner CP, Gonik B, editors. High risk pregnancy. 3nd Philadelphia: Elsevier Saunders; 2005. P. 43-63.
  8. Ansari J, Behjati F, Kahrizi K, Ghasem Firouzabadi S, Ataei Kachoui M, Najmabadi H. Investigation of chromosome subtelomeric abnormalities in some Iranian patients with idiopathic mental retardation using Fluorescent In Situ Hybridization (FISH) technique. Journal of Genetics 2009; 3(3):15-20.
  9. Cunningham FG, Leveno KJ, Bloom SL, Spong CY, Dash JS, Hoffman BL, et al. Williams Obstetrics. 23nd ed . New York: McGraw-Hill; 2010.
  10. Yeo L, Vintzileos A. Second Trimester Screening for Fetal Abnormalities. James DK, Steer P, Weiner C, Gonik B, Crowther C, Robson S. High Risk Pregnancy Management Options. 4nd Elsevier Saunders. 2011. P.131-5.
  11. Nyberg DA, Kramer D, Resta RG, Kapur R, Mahony BS, Luthy DA, et al. Prenatal sonographic findings of trisomy 18: review of 47 cases. Journal of ultrasound in medicine 1993; 12(2):103-13.
  12. Yeo L, Guzman ER, Day-Salvatore D, Walters C, Chavez D, Vintzileos AM. Prenatal detection of fetal trisomy 18 through abnormal sonographic features. Journal of ultrasound in medicine 2003; 22(6):581-90.
  13. Lehman CD, Nyberg DA, Winter 3rd TC, Kapur RP, Resta RG, Luthy DA. Trisomy 13 syndrome: prenatal US findings in a review of 33 cases. Radiology 1995; 194(1):217-22.
  14. Cicero S, Johnson JM, Nicolaides K. Sonographic markers of fetal chromosomal defects. Diagnostic Ultrasound. 3rd ed. St Louis, MO: Elsevier Mosby 2005: 1157-83.
  15. Jeanty P, Clavelli w, Romaris S. Ultrasound Detection of Chromosomal Anomalies. In: Fleischer A, Toy E. Lee W, Manning F, Romero R. Sonography in Obstetries and Gynecology: Principles and Practice. 7nd McGraw-Hill Medical; 2011. P. 670-2.
  16. Singh C, Biswas A. Impact of gestational age on nuchal fold thickness in the second trimester. Journal of Ultrasound in Medicine 2014; 33(4):687-90.
  17. Gonzalez R, Aedo S, Dezerega V, Sepulveda W. Frontonasal Fold Thickness–to–Nasal Bone Length Ratio as a Prenatal Sonographic Marker for Trisomy 21 in a Low‐Risk Population. Journal of Ultrasound in medicine 2013; 32(5):795-800.
  18. Persico N, Borenstein M, Molina F, Azumendi G, Nicolaides KH. Prenasal thickness in trisomy‐21 fetuses at 16–24 weeks of gestation. Ultrasound in Obstetrics and Gynecology: The Official Journal of the International Society of Ultrasound in Obstetrics and Gynecology 2008; 32(6):751-4.
  19. Maymon R, Levinsohn‐Tavor O, Cuckle H, Tovbin Y, Dreazen E, Wiener Y, et al. Second trimester ultrasound prenasal thickness combined with nasal bone length: a new method of Down syndrome screening. Prenatal Diagnosis: Published in Affiliation With the International Society for Prenatal Diagnosis 2005; 25(10):906-11.
  20. Hashemi Attar AM, Afzali N, Naghibi S, Memar M. The ratio of Prenasal thickness to nasal bone length in fetal screening ultrasonography at second trimester of pregnancy. Iran J Obstet Gynecol Infertil 2017; 19(39): 8-17.
  21. Cho JY, Kim KW, Lee YH, Toi A. Measurement of nuchal skin fold thickness in the second trimester: influence of imaging angle and fetal presentation. Ultrasound in Obstetrics and Gynecology: The Official Journal of the International Society of Ultrasound in Obstetrics and Gynecology 2005; 25(3):253-7.
  22. Kazemi K, Adibi A, Hovsepian S. Reference values of nuchal fold thickness in an Iranian population sample. Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences 2018; 23.
  23. Ma L, Luo Y, Rong L, Huo P, Gao J, Li Y. Correlation of thickened nuchal fold with fetal chromosomal abnormalities among 919 cases. Zhonghua yi xue yi Chuan xue za zhi= Zhonghua Yixue Yichuanxue Zazhi= Chinese Journal of Medical Genetics 2019; 36(9):874-6.
  24. Tekesin I. The diagnostic value of a detailed first trimester anomaly scan in fetuses with increased nuchal translucency thickness. Journal of Perinatal Medicine 2019; 47(2):241-6.
  25. Wang Q, Wang X, Wu Q. Relationship between first trimester nuchal septations and chromosomal anomalies. Clinical Imaging 2020; 60(1):1-4.
The Iranian Journal of Obstetrics, Gynecology and Infertility
Volume 26, Issue 4
June 2023
Pages 36-45

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