External validation of models to estimate gestational age in the second and third trimester using ultrasound: A prospective multicentre observational study.
biometry
due date
gestational age
growth
post‐term
pregnancy
pregnancy dating
preterm
screening
ultrasound dating
Journal
BJOG : an international journal of obstetrics and gynaecology
ISSN: 1471-0528
Titre abrégé: BJOG
Pays: England
ID NLM: 100935741
Informations de publication
Date de publication:
08 Aug 2024
08 Aug 2024
Historique:
revised:
24
06
2024
received:
06
04
2024
accepted:
13
07
2024
medline:
9
8
2024
pubmed:
9
8
2024
entrez:
8
8
2024
Statut:
aheadofprint
Résumé
Accurate assessment of gestational age (GA) is important at both individual and population levels. The most accurate way to estimate GA in women who book late in pregnancy is unknown. The aim of this study was to externally validate the accuracy of equations for GA estimation in late pregnancy and to identify the best equation for estimating GA in women who do not receive an ultrasound scan until the second or third trimester. This was a prospective, observational cross-sectional study. 57 prenatal care centres, France. Women with a singleton pregnancy and a previous 11-14-week dating scan that gave the observed GA were recruited over an 8-week period. They underwent a standardised ultrasound examination at one time point during the pregnancy (15-43 weeks), measuring 12 foetal biometric parameters that have previously been identified as useful for GA estimation. A total of 189 equations that estimate GA based on foetal biometry were examined and compared with GA estimation based on foetal CRL. Comparisons between the observed GA and the estimated GA were made using R A total of 2741 pregnant women were examined. After exclusions, 2339 participants were included. In the 20 best performing equations, the intercept ranged from -0.22 to 0.30, the calibration slope from 0.96 to 1.03 and the RSME from 0.67 to 0.87. Overall, multiparameter models outperformed single-parameter models. Both the 95% range of error and mean difference increased with gestation. Commonly used models based on measurement of the head circumference alone were not amongst the best performing models and were associated with higher 95% error and mean difference. We provide strong evidence that GA-specific equations based on multiparameter models should be used to estimate GA in late pregnancy. However, as all methods of GA assessment in late pregnancy are associated with large prediction intervals, efforts to improve access to early antenatal ultrasound must remain a priority. The proposal for this study and the corresponding methodological review was registered on PROSPERO international register of systematic reviews (registration number: CRD4201913776).
Identifiants
pubmed: 39118202
doi: 10.1111/1471-0528.17922
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Informations de copyright
© 2024 The Author(s). BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.
Références
Self A, Daher L, Schlussel M, Roberts N, Ioannou C, Papageorghiou AT. Second and third trimester estimation of gestational age using ultrasound or maternal symphysis‐fundal height measurements: a systematic review. BJOG. 2022;129(9):1447–1458.
Blencowe H, Cousens S, Oestergaard MZ, Chou D, Moller AB, Narwal R, et al. National, regional, and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications. Lancet. 2012;379(9832):2162–2172.
Statistics South Africa. Maternal Health Indicators Media Release 2020. Available from: http://www.statssa.gov.za/?p=13100&gclid=CjwKCAjwieuGBhAsEiwA1Ly_nS‐sNpoXDRQ9ZN3Z8Cfx8‐SoBAJhvXD4wgTWMSagA7hFK4dy‐LhHzhoC8X8QAvD_BwE
Kaswa R, Rupesinghe GFD, Longo‐Mbenza B. Exploring the pregnant women's perspective of late booking of antenatal care services at Mbekweni health Centre in Eastern Cape, South Africa. Afr J Prim Health Care Fam Med. 2018;10(1):e1–e9.
Uganda Bureau of Statistics (UBOS) and ICF. Uganda demographic and health survey 2016. Kampala, Uganda and Rockville, Maryland, USA: UBOS and ICF; 2018. p. 150.
Osterman MJK, Martin JA. Timing and adequacy of prenatal care in the United States, 2016. Natl Vital Stat Rep. 2018;67(3):1–14.
NHS Digital. Hospital episode statistics provider level analysis 2017‐18 to 2018‐19. Leeds: Health and Social Care Information Centre; 2019.
Alderliesten ME, Vrijkotte TG, van der Wal MF, Bonsel GJ. Late start of antenatal care among ethnic minorities in a large cohort of pregnant women. BJOG. 2007;114(10):1232–1239.
Nguyen TH, Larsen T, Engholm G, Moller H. Increased adverse pregnancy outcomes with unreliable last menstruation. Obstet Gynecol. 2000;95(6 Pt 1):867–873.
World Health Organisation. WHO recommendations on antenatal care for a positive pregnancy experience 2016. Available from: https://www.who.int/publications/i/item/9789241549912
Papageorghiou AT, Kemp B, Stones W, Ohuma EO, Kennedy SH, Purwar M, et al. Ultrasound‐based gestational‐age estimation in late pregnancy. Ultrasound Obstet Gynecol. 2016;48(6):719–726.
Butt K, Lim KI. Guideline No. 388‐determination of gestational age by ultrasound. J Obstet Gynaecol Can. 2019;41(10):1497–1507.
Hadlock FP. Sonographic estimation of fetal age and weight. Radiol Clin North Am. 1990;28(1):39–50.
Degani S. Fetal biometry: clinical, pathological, and technical considerations. Obstet Gynecol Surv. 2001;56(3):159–167.
Kuleva M, Castaing O, Fries N, Bernard JP, Bussières L, Fontanges M, et al. A standardized approach for the assessment of the lower uterine segment at first trimester by transvaginal ultrasound: a flash study. J Matern Fetal Neonatal Med. 2016;29(9):1376–1381.
Kuleva M, Fries N, Castaing O, Moeglin D, Salomon LJ. Flash study' on chorionicity determination from ultrasound images at 11‐14 weeks' gestation in twin pregnancies. Ultrasound Obstet Gynecol. 2013;41(4):471–472.
Stirnemann JJ, Fries N, Bessis R, Fontanges M, Mangione R, Salomon LJ. Implementing the INTERGROWTH‐21(st) fetal growth standards in France: a ‘flash study’ of the college Français d'Echographie Foetale (CFEF). Ultrasound Obstet Gynecol. 2017;49(4):487–492.
Salomon LJ. How to date pregnancy? J Gynecol Obstet Biol Reprod. 2011;40(8):726–733.
Robinson HP, Fleming JE. A critical evaluation of sonar "crown‐rump length" measurements. Br J Obstet Gynaecol. 1975;82(9):702–710.
Akhtar W, Ali A, Arain MA, Saeed F, Siddiqui S, Memon A. Sonographic fetal biometry charts for a Pakistani cohort. East Mediterr Health J. 2011;17(12):969–975.
Akram M, Farooqi U, Arif N, Riaz A, Yousaf M, Fatima M, et al. Estimation of gestational age from fetal kidney length in the second and third trimester of pregnancy by ultrasonography. Saudi Pharm J. 2019;5:222–229.
Chervenak FA, Skupski DW, Romero R, Myers MK, Smith‐Levitin M, Rosenwaks Z, et al. How accurate is fetal biometry in the assessment of fetal age? Am J Obstet Gynecol. 1998;178(4):678–687.
Gupta D, Gupta H, Zaidi Z, Saxena D, Gupta R. Accuracy in estimation of gestational age in third trimester by fetal kidney length in Indian women. Indian J Clin Pract. 2013;24(5):459–463.
Hill LM, Guzick D, Hixson J, Peterson CS, Rivello DM. Composite assessment of gestational age: a comparison of institutionally derived and published regression equations. Am J Obstet Gynecol. 1992;166(2):551–555.
Kaul I, Menia V, Anand AK, Gupta R. Role of fetal kidney length in estimation of gestational age. JK Sci. 2011;14(2):65–69.
Mahale NA, Devi A, Mahale A, Ullal S, Fernandes M, Prabhu S. Ultrasonic assessment of gestational age by measurement of fetal kidney length in third trimester. G Ital Ostet Ginecol. 2019;41(1):10–13.
Osho ES, Ibitoye BO, Adetiloye VA, Adeyemi AB, Aderibigbe AS, Omisore AD. Ultrasonic determination of gestational age by assessment of fetal kidney size in the third trimester in southwest Nigeria. Int J Gynaecol Obstet. 2019;144(3):271–276.
Ozat M, Kanat‐Pektas M, Gungor T, Gurlek B, Caglar M. The significance of fetal sacral length in the ultrasonographic assessment of gestational age. Arch Gynecol Obstet. 2011;283(5):999–1004.
Piantelli G, Sacchini C, Coltri A, Ludovici G, Paita Y, Gramellini D. Ultrasound dating‐curve analysis in the assessment of gestational age. Clin Exp Obstet Gynecol. 1994;21(2):108–118.
Schmidt W, Hendrik H. Fetal femur length in the 2d and 3d trimester of pregnancy. Geburtshilfe Frauenheilkd. 1985;45(2):91–97.
Varol F, Saltik A, Kaplan PB, Kilic T, Yardim T. Evaluation of gestational age based on ultrasound fetal growth measurements. Yonsei Med J. 2001;42(3):299–303.
Al Hindawi ZM. Ultrasonographic assessment of duration of pregnancy by utilizing fetus kidney length in second and third trimester. Int J Pharm Res. 2020;12(4):1850–1856.
Altman DG, Chitty LS. New charts for ultrasound dating of pregnancy. Ultrasound Obstet Gynecol. 1997;10(3):174–191.
Chang CH, Chang FM, Yu CH, Ko HC, Chen HY. Three‐dimensional ultrasound in the assessment of fetal cerebellar transverse and antero‐posterior diameters. Ultrasound Med Biol. 2000;26(2):175–182.
Chang CH, Chang FM, Yu CH, Yao BL, Ko HC. Fetal head circumference in normal pregnancy: remodeling by Altman's method. J Med Ultrasound. 1998;6(2):61–67.
Chang CH, Chang FM, Yu CH, Yao BL, Liang RI, Ko HC. Re‐analysis of fetal biparietal diameter during gestation in Taiwanese by Altman's method. J Med Ultrasound. 1996;4(4):162–168.
Chang CH, Chang FM, Yu CH, Yao BL, Liang RI, Ko HC, et al. Fetal occipito‐frontal diameter in normal pregnancy: reappraisal by Altman's model. J Med Ultrasound. 1997;5(1):5–11.
Chang FM, Ko HC, Chang CH, Yu CH, Liang RI, Yao BL, et al. Fetal tibia length assessment by prenatal ultrasound: part I. Using absolute residuals for constructing age‐related reference percentiles. J Med Ultrasound. 1997;5(2):49–56.
Chavez MR, Ananth CV, Smulian JC, Yeo L, Oyelese Y, Vintzileos AM. Fetal transcerebellar diameter measurement with particular emphasis in the third trimester: a reliable predictor of gestational age. Am J Obstet Gynecol. 2004;191(3):979–984.
Dare FO, Smith NC, Smith P. Ultrasonic measurement of biparietal diameter and femur in foetal age determination. West Afr J Med. 2004;23(1):24–26.
De Crespigney LC, Speirs AL. A new look at biparietal diameter. Aust N Z J Obstet Gynaecol. 1989;29(1):26–29.
Dilmen G, Turhan NO, Toppare MF, Seckin N, Ozturk M, Goksin E. Scapula length measurement for assessment of fetal growth and development. Ultrasound Med Biol. 1995;21(2):139–142.
Edevbie JP, Akhigbe AO. Ultrasound measurement of fetal kidney length in normal pregnancy and correlation with gestational age. Niger J Clin Pract. 2018;21(8):960–966.
Eze CU, Onu IU, Adeyomoye AA, Upeh ER. Estimation of gestational age using trans‐cerebellar diameter: a sonographic study of a cohort of healthy pregnant women of Igbo ethnic origin in a suburb of Lagos, southwest Nigeria. J Ultrasound. 2020;19:19.
Eze CU, Onwuzu QE, Nwadike IU. Sonographic reference values for fetal transverse cerebellar diameter in the second and third trimesters in a Nigerian population. J Diagn Med Sonogr. 2017;33(3):174–181.
Gameraddin G, Suliman S, Yousef Y. Evaluation of gestational age with fetal foot length using ultrasonography. J Am Sci. 2014;10:5–7.
Ghai R, Singla M, Goel P, Khare S, Jain S, Agrawal S. Ultrasonic measurement of foetal biparietal diameter and its correlation to gestational age in the garhwali population. Indian J Public Health Res Dev. 2011;2(1):74–77.
Hadlock FP, Deter RL, Harrist RB, Park SK. Fetal biparietal diameter: a critical re‐evaluation of the relation to menstrual age by means of real‐time ultrasound. J Ultrasound Med. 1982;1(3):97–104.
Hadlock FP, Deter RL, Harrist RB, Park SK. Fetal abdominal circumference as a predictor of menstrual age. AJR Am J Roentgenol. 1982;139(2):367–370.
Hadlock FP, Deter RL, Harrist RB, Park SK. Fetal head circumference: relation to menstrual age. AJR Am J Roentgenol. 1982;138(4):649–653.
Hadlock FP, Deter RL, Harrist RB, Park SK. Computer assisted analysis of fetal age in the third trimester using multiple fetal growth parameters. J Clin Ultrasound. 1983;11(6):313–316.
Hadlock FP, Harrist RB, Deter RL, Park SK. Fetal femur length as a predictor of menstrual age: sonographically measured. AJR Am J Roentgenol. 1982;138(5):875–878.
Hadlock FP, Deter RL, Harrist RB, Park SK. Estimating fetal age: computer‐assisted analysis of multiple fetal growth parameters. Radiology. 1984;152(2):497–501.
Hegab M, Midan MF, Taha T, Bibars M, Wakeel KHE, Amer H, et al. Fetal biometric charts and reference equations for pregnant women living in Port Said and Ismailia governorates in Egypt. Open Access Maced J Med Sci. 2018;6(5):751–756.
Hemraj S, Abraham SM, Acharya D, Ravichandra G, Vinayaka US. Sonographic correlation of gestational age with fetal kidney length. Int J Infertil Fetal Med. 2016;7(2):37–41.
Holanda‐Filho JA, Souza AI, Souza AS, Figueroa JN, Ferreira AL, Cabral‐Filho JE. Fetal transverse cerebellar diameter measured by ultrasound does not differ between genders. Arch Gynecol Obstet. 2011;284(2):299–302.
Honarvar M, Allahyari M, Dehbashi S. Assessment of gestational age based on ultrasonic femur length after the first trimester: a simple mathematical correlation between gestational age (GA) and femur length (FL). Int J Gynaecol Obstet. 2000;70(3):335–340.
Jiang X, Zhang YH, Li Y, Ma X, Zhu YS, Shang L. Reference charts and equations of fetal biometry for normal singleton pregnant women in Shaanxi, China. Clin Exp Obstet Gynecol. 2013;40(3):393–398.
Johnsen SL, Rasmussen S, Sollien R, Kiserud T. Fetal age assessment based on ultrasound head biometry and the effect of maternal and fetal factors. Acta Obstet Gynecol Scand. 2004;83(8):716–723.
Johnsen SL, Rasmussen S, Sollien R, Kiserud T. Fetal age assessment based on femur length at 10‐25 weeks of gestation, and reference ranges for femur length to head circumference ratios. Acta Obstet Gynecol Scand. 2005;84(8):725–733.
Karabulut AK, Koyluoglu B, Uysal I. Human foetal sacral length measurement for the assessment of foetal growth and development by ultrasonography and dissection. Anat Histol Embryol. 2001;30(3):141–146.
Konje JC, Abrams KR, Bell SC, Taylor DJ. Determination of gestational age after the 24th week of gestation from fetal kidney length measurements. Ultrasound Obstet Gynecol. 2002;19(6):592–597.
Leung TN, Pang MW, Daljit SS, Leung TY, Poon CF, Wong SM, et al. Fetal biometry in ethnic Chinese: biparietal diameter, head circumference, abdominal circumference and femur length. Ultrasound Obstet Gynecol. 2008;31(3):321–327.
Mahmoud MZ, Mahmoud O, Abdulla A. Fetal transverse cerebellar diameter measurement for prediction of gestational age in pregnant Sudanese ladies. Int J Life Sci Med Res. 2013;3:89–93.
Marinho AO, Bamgboye EA. Assessment of foetal femur length by ultrasound in a normal Nigerian obstetric population. Afr J Med Med Sci. 1987;16(2):47–52.
AMANHI. Performance of late pregnancy biometry for gestational age dating in low‐income and middle‐income countries: a prospective, multicountry, population‐based cohort study from the WHO Alliance for maternal and newborn health improvement (AMANHI) study group. Lancet Global Health. 2020;8(4):e545–e554.
Mercer BM, Sklar S, Shariatmadar A, Gillieson MS, D'Alton ME. Fetal foot length as a predictor of gestational age. Am J Obstet Gynecol. 1987;156(2):350–355.
Mongelli M, Chew S, Yuxin NG, Biswas A. Third‐trimester ultrasound dating algorithms derived from pregnancies conceived with artificial reproductive techniques. Ultrasound Obstet Gynecol. 2005;26(2):129–131.
Nwadike UI, Agwu KK, Eze CU, Okpala OC, Onu AO. Sonographic biometry of Fetal interorbital distance as a predictor of gestational age in Enugu, Southeast Nigeria. West Indian Med J. 2016;65(1):128–133.
Orji MO, Adeyekun AA. Ultrasound estimation of foetal gestational age by transcerebellar diameter in healthy pregnant nigerian women. West Afr J Med. 2014;33(1):61–67.
Osinusi BO, Ogunseyinde O. Ultrasonic foetal abdominal circumference as a means of assessing gestational age in Nigerians. Afr J Med Med Sci. 1989;18(2):101–104.
Osinusi BO, Okubanjo OA. Ultrasonic foetal head circumference as a means of assessing gestational age in Nigerians. West Afr J Med. 1990;9(1):22–25.
Ott WJ. Accurate gestational dating: revisited. Am J Perinatol. 1994;11(6):404–408.
Ott WJ. Accurate gestational dating. Obstet Gynecol. 1985;66(3):311–315.
Persson PH, Weldner BM. Reliability of ultrasound fetometry in estimating gestational age in the second trimester. Acta Obstet Gynecol Scand. 1986;65(5):481–483.
Persson PH, Weldner BM. Normal range growth curves for fetal biparietal diameter, occipito frontal diameter, mean abdominal diameters and femur length. Acta Obstet Gynecol Scand. 1986;65(7):759–761.
Quinlan RW, Brumfield C, Martin M, Cruz AC. Ultrasonic measurement of femur length as a predictor of fetal gestational age. J Reprod Med. 1982;27(7):392–394.
Reddy RH, Prashanth K, Ajit M. Significance of foetal transcerebellar diameter in foetal biometry: a pilot study. J Clin Diagn Res. 2017;11(6):TC01–TC04.
Rodriguez‐Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M, et al. Fetal cerebellar growth and Sylvian fissure maturation: international standards from fetal growth longitudinal study of INTERGROWTH‐21st project. Ultrasound Obstet Gynecol. 2021;57(4):614–623.
Sabbagha RE, Turner JH, Rockette H, Mazer J, Orgill J. Sonar BPD and fetal age. Definition of the relationship. Obstet Gynecol. 1974;43(1):7–14.
Satish Prasad BS, Likhitha S. Cerebellar measurements with ultrasonography in the evaluation of fetal age. IOSR J Dent Med Sci. 2014;13(9):49–56.
Schluter PJ, Pritchard G, Gill MA. Using ultrasonic fetal size measurements to estimate gestational age in Brisbane, Australia. Australas Radiol. 2007;51(1):46–52.
Selbing A, Kjessler B. Conceptual dating by ultrasonic measurement of the fetal biparietal diameter in early pregnancy. Acta Obstet Gynecol Scand. 1985;64(7):593–597.
Senapati S, Behera SS, Chinara PK. Relationship of umbilical cord size with gestational age: a sonographic study. Paripex Indian J Res. 2016;5(4):434–439.
Skupski DW, Owen J, Kim S, Fuchs KM, Albert PS, Grantz KL, et al. Estimating gestational age from ultrasound fetal biometrics. Obstet Gynecol. 2017;130(2):433–441.
Sun JF, Zhang LJ, Cui LQ, Luo XD, He GH, Dong XJ, et al. Gestational age estimation from ultrasound fetal biometrics in China. Clin Exp Obstet Gynecol. 2020;47(5):714–722.
Swapnil P, Vilas C, Varsha P. Correlation between gestational age and abdominal circumference in second trimester. Indian J Forensic Med Toxicol. 2021;15(1):440–444.
Tongsong T, Wanapirak C, Jesadapornchai S, Tathayathikom E. Fetal binocular distance as a predictor of menstrual age. Int J Gynaecol Obstet. 1992;38(2):87–91.
Tse CH, Lee KW. A comparison of the fetal femur length and biparietal diameter in predicting gestational age in the third trimester. Aust N Z J Obstet Gynaecol. 1984;24(3):186–188.
Uerpairojkit B, Charoenvidhya D, Manotaya S, Tanawattanachareon S, Wacharaprechanont T, Tannirandorn Y. Fetal transverse cerebellar diameter in Thai population. J Med Assoc Thai. 2001;84(Suppl 1):S346–S351.
Ugur MG, Mustafa A, Ozcan HC, Tepe NB, Kurt H, Akcil E, et al. Fetal kidney length as a useful adjunct parameter for better determination of gestational age. Saudi Med J. 2016;37(5):533–537.
Varsha P, Swapnil P, Bharat P. Correlation between gestational age and head circumference in third trimester. Indian J Forensic Med Toxicol. 2020;14(4):273–279.
Verburg BO, Steegers EA, De Ridder M, Snijders RJ, Smith E, Hofman A, et al. New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population‐based cohort study. Ultrasound Obstet Gynecol. 2008;31(4):388–396.
Viveki PR, Shirol VS. Establishment of reference tables for fetal abdominal circumference by ultrasonographic measurements in local population, Karnataka, India. Indian J Public Health Res Dev. 2019;10(6):44–50.
Warda AH, Deter RL, Rossavik IK, Carpenter RJ, Hadlock FP. Fetal femur length: a critical reevaluation of the relationship to menstrual age. Obstet Gynecol. 1985;66(1):69–75.
Westerway SC, Davison A, Cowell S. Ultrasonic fetal measurements: new Australian standards for the new millennium. Aust N Z J Obstet Gynaecol. 2000;40(3):297–302.
Yagel S, Adoni A, Oman S, Wax Y, Hochner‐Celnikier D. A statistical examination of the accuracy of combining femoral length and biparietal diameter as an index of fetal gestational age. Br J Obstet Gynaecol. 1986;93(2):109–115.
Archer L, Snell KIE, Ensor J, Hudda MT, Collins GS, Riley RD. Minimum sample size for external validation of a clinical prediction model with a continuous outcome. Stat Med. 2021;40(1):133–146.
Chavez MR, Ananth CV, Smulian JC, Vintzileos AM. Fetal transcerebellar diameter measurement for prediction of gestational age at the extremes of fetal growth. J Ultrasound Med. 2007;26(9):1167; quiz 73–4–1171.
McMillen IC, Adams MB, Ross JT, Coulter CL, Simonetta G, Owens JA, et al. Fetal growth restriction: adaptations and consequences. Reproduction. 2001;122(2):195–204.
Koech A, Musitia PM, Mwashigadi GM, Kinshella MW, Vidler M, Temmerman M, et al. Acceptability and feasibility of a low‐cost device for gestational age assessment in a low‐resource setting: qualitative study. JMIR Hum Factors. 2022;9(4):e34823.
Chamberlain PF, Manning FA, Morrison I, Harman CR, Lange IR. Ultrasound evaluation of amniotic fluid volume. I. The relationship of marginal and decreased amniotic fluid volumes to perinatal outcome. Am J Obstet Gynecol. 1984;150(3):245–249.
Zilianti M, Fernández S. Correlation of ultrasonic images of fetal intestine with gestational age and fetal maturity. Obstet Gynecol. 1983;62(5):569–573.
Gentili P, Trasimeni A, Giorlandino C. Fetal ossification centers as predictors of gestational age in normal and abnormal pregnancies. J Ultrasound Med. 1984;3(5):193–197.
Petrucha RA, Platt LD. Relationship of placental grade to gestational age. Am J Obstet Gynecol. 1982;144(6):733–735.
Malik R, Pandya VK, Shrivastava P. Gestational age estimation using transcerebellar diameter with grading of fetal cerebellum and evaluation of TCD/AC (Transcerebellar diameter/abdominal circumference) ratio as a gestational age independent parameter. Indian J Radiol Imag. 2003;13(1):95–97.
Hashimoto K, Shimizu T, Shimoya K, Kanzaki T, Clapp JF, Murata Y. Fetal cerebellum: US appearance with advancing gestational age. Radiology. 2001;221(1):70–74.
Lee LH, Bradburn E, Craik R, Yaqub M, Norris SA, Ismail LC, et al. Machine learning for accurate estimation of fetal gestational age based on ultrasound images. NPJ Digit Med. 2023;6(1):36.
Burgos‐Artizzu XP, Coronado‐Gutiérrez D, Valenzuela‐Alcaraz B, Vellvé K, Eixarch E, Crispi F, et al. Analysis of maturation features in fetal brain ultrasound via artificial intelligence for the estimation of gestational age. Am J Obstet Gynecol. 2021;3(6):100462.
Fung R, Villar J, Dashti A, Ismail LC, Staines‐Urias E, Ohuma EO, et al. Achieving accurate estimates of fetal gestational age and personalised predictions of fetal growth based on data from an international prospective cohort study: a population‐based machine learning study. Lancet Digital Health. 2020;2(7):e368–e375.
Napolitano R, Donadono V, Ohuma EO, Knight CL, Wanyonyi SZ, Kemp B, et al. Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study. Ultrasound Obstet Gynecol. 2016;48(1):80–85.