Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort

Ömer Osman Eroğlu; Cansın Eroğlu; Sait Erbey; Mehmet Alican Sapmaz; Bilge Erbey; Murat Polat; Çağanay Soysal

Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort

Abstract

Aims: To assess the fit of the INTERGROWTH-21st newborn standards to the birth weight distribution of a Turkish tertiary cohort. Methods: Retrospective analysis of 41 967 live singleton births at 24-42 gestational weeks (2022-2026), classified as small (SGA) or large for gestational age (LGA) with the INTERGROWTH-21st standard (≥33 weeks) and very preterm reference (<33 weeks). Gestational age was recorded in completed weeks; the mid-week (week+3) value was used and all seven day assumptions tested. Proportions at seven percentiles were compared with nominal values by exact binomial tests; a probit fit gave location and scale estimates. Results: SGA prevalence was 8.3% and LGA 10.3%; the z-score distribution was estimated as mean +0.07, standard deviation 0.97. After correction for multiple comparisons, departures were confined to the lower half (below the median 45.9% vs 50%; all p<0.001); upper-tail proportions stayed close to nominal. Under the mid-week assumption 3479 newborns were SGA, 718 fewer than the 4197 expected at 10%. Across the seven assumptions SGA prevalence ranged from 5.8% to 11.0%, reclassifying up to 4547 newborns (10.8%). Adolescent maternal age [adjusted odds ratio (aOR) 1.49; 95% CI 1.31-1.71] and foreign nationality (aOR 1.28; 1.17-1.40) remained associated with SGA. Conclusion: Under the prespecified mid-week assumption, the standards fit this cohort closely but classify 718 fewer newborns as SGA than the nominal 10% implies, leaving them outside the threshold that prompts further assessment. Because classification is sensitive to the assumed day, prevalence from week-only registries should be reported with that assumption.

Keywords

References

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Details

Primary Language

English

Subjects

Obstetrics and Gynaecology

Journal Section

Research Article

Authors

Ömer Osman Eroğlu ^*
0000-0001-9861-6767
Türkiye

Cansın Eroğlu
0009-0004-5049-1415
Türkiye

Sait Erbey
0009-0007-1950-9041
Türkiye

Mehmet Alican Sapmaz
0000-0003-3812-3455
Türkiye

Bilge Erbey
0009-0004-4989-4970
Türkiye

Murat Polat
0009-0002-2964-729X
Türkiye

Çağanay Soysal
0000-0002-4381-6099
Türkiye

Publication Date

October 25, 2026

Submission Date

July 14, 2026

Acceptance Date

August 22, 2026

Published in Issue

Year 2026 Volume: 8 Number: 6

IZ

https://izlik.org/JA79TF39LD

Cite

RIS / Bibtex

APA

Eroğlu, Ö. O., Eroğlu, C., Erbey, S., Sapmaz, M. A., Erbey, B., Polat, M., & Soysal, Ç. (2026). Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort. Anatolian Current Medical Journal, 8(6), 1122-1129. https://izlik.org/JA79TF39LD

AMA

1.Eroğlu ÖO, Eroğlu C, Erbey S, et al. Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort. Anatolian Curr Med J / ACMJ / acmj. 2026;8(6):1122-1129. https://izlik.org/JA79TF39LD

Chicago

Eroğlu, Ömer Osman, Cansın Eroğlu, Sait Erbey, et al. 2026. “Distributional Calibration of the INTERGROWTH-21st Newborn Standards in a Turkish Tertiary Birth Cohort”. Anatolian Current Medical Journal 8 (6): 1122-29. https://izlik.org/JA79TF39LD.

EndNote

Eroğlu ÖO, Eroğlu C, Erbey S, Sapmaz MA, Erbey B, Polat M, Soysal Ç (October 1, 2026) Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort. Anatolian Current Medical Journal 8 6 1122–1129.

IEEE

[1]Ö. O. Eroğlu et al., “Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort”, Anatolian Curr Med J / ACMJ / acmj, vol. 8, no. 6, pp. 1122–1129, Oct. 2026, [Online]. Available: https://izlik.org/JA79TF39LD

ISNAD

Eroğlu, Ömer Osman - Eroğlu, Cansın - Erbey, Sait - Sapmaz, Mehmet Alican - Erbey, Bilge - Polat, Murat - Soysal, Çağanay. “Distributional Calibration of the INTERGROWTH-21st Newborn Standards in a Turkish Tertiary Birth Cohort”. Anatolian Current Medical Journal 8/6 (October 1, 2026): 1122-1129. https://izlik.org/JA79TF39LD.

JAMA

1.Eroğlu ÖO, Eroğlu C, Erbey S, Sapmaz MA, Erbey B, Polat M, Soysal Ç. Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort. Anatolian Curr Med J / ACMJ / acmj. 2026;8:1122–1129.

MLA

Eroğlu, Ömer Osman, et al. “Distributional Calibration of the INTERGROWTH-21st Newborn Standards in a Turkish Tertiary Birth Cohort”. Anatolian Current Medical Journal, vol. 8, no. 6, Oct. 2026, pp. 1122-9, https://izlik.org/JA79TF39LD.

Vancouver

1.Ömer Osman Eroğlu, Cansın Eroğlu, Sait Erbey, Mehmet Alican Sapmaz, Bilge Erbey, Murat Polat, Çağanay Soysal. Distributional calibration of the INTERGROWTH-21st newborn standards in a Turkish tertiary birth cohort. Anatolian Curr Med J / ACMJ / acmj [Internet]. 2026 Oct. 1;8(6):1122-9. Available from: https://izlik.org/JA79TF39LD