# NICHD Fetal Growth Studies Study · id `maternal:nichd-fetal-growth-studies` · Maternal & Newborn Atlas · release `fc5a600ec7387e71` (public) > General information from published sources, not medical advice, and not reviewed by clinicians. Check the cited source before relying on anything here. The atlas's own text and curation may be reused under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0, https://creativecommons.org/licenses/by-nc/4.0/): credit the atlas, and do not use it commercially. See the atlas About page. Text quoted from a source stays under that source's own terms, given as the source's reuse\_basis. The atlas's reuse terms do not cover it. The downloads list each quotation with its source in third\_party\_quotations. Browse, life stage: Pregnancy Browse, care area: The baby before birth ## In plain language A US study that followed 2334 healthy women with low-risk pregnancies from four racial and ethnic groups with repeated scans, to see whether fetal growth charts should differ by group. It found that fetal weight differed significantly between the groups after 20 weeks, and it published a separate standard for each group. ## Technical summary Prospective cohort of 2334 healthy women with low-risk singleton pregnancies recruited from 12 community and perinatal centres from July 2009 through January 2013; the fetuses of 1737 women who stayed low risk at birth were used for the standards (Am J Obstet Gynecol 2015). A later expert review compared the approach with INTERGROWTH-21st and a WHO study (PMID 29275821). One of three growth standards that do not agree (see the bottleneck page). PubMed grant details list NICHD contracts. Only the abstract was read. ## Key facts - Design: Prospective longitudinal cohort. Women were screened at 8 weeks 0 days to 13 weeks 6 days and randomized among 4 ultrasonography schedules for longitudinal fetal measurement. Racial/ethnic-specific growth curves were estimated using linear mixed models with cubic splines. - Phase: Not reported - Enrolled: 2334 women (healthy women with low-risk singleton pregnancies recruited) (enrolled count; Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies, snapshot `maternal:pubmed-26410205-2026-10-14`, retrieved 2026-10-14); 1737 women (whose fetuses continued to be low risk at birth and whose measurements went into the standards) (analyzed count; Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies, snapshot `maternal:pubmed-26410205-2026-10-14`, retrieved 2026-10-14) - Started: Not reported - Primary completion: Not reported - Completion: Not reported - Countries: Not reported - Care setting: Not reported - Registry status: Not reported ## Claims, with the population each applies to ## Context: Fetuses of healthy women with low-risk singleton pregnancies in four US racial and ethnic groups (NICHD Fetal Growth Studies) Recipient: Fetal; Population: Fetuses of 1737 women (of 2334 recruited) who stayed low risk at birth (uncomplicated pregnancy, no anomalies): non-Hispanic white, non-Hispanic Black, Hispanic and Asian women, self-identified. Women were aged 18 to 40 years with a body mass index of 19.0 to 29.9 kg/m2, healthy lifestyles and living conditions, and a low-risk medical and obstetric history. The women are the people recruited; the fetuses are the people measured.; Care setting: 12 community and perinatal centres; Geography: United States (the abstract says four US racial/ethnic groups and does not name states); Life stage: Pregnancy; women were screened at 8 weeks 0 days to 13 weeks 6 days, then followed with scheduled ultrasound; Gestational age: 8 weeks 0 days (56 days) to 13 weeks 6 days (97 days), measured at enrolment; Postnatal age: Not reported; Follow-up: Women were randomized among 4 ultrasonography schedules for longitudinal fetal measurement; 92% of recruited women completed the protocol ### The NICHD Fetal Growth Studies recruited 2334 healthy women with low-risk singleton pregnancies from 12 community and perinatal centres between July 2009 and January 2013: 614 non-Hispanic white, 611 non-Hispanic Black, 649 Hispanic and 460 Asian women. The fetuses of 1737 women (74%) stayed low risk at birth, and their measurements went into the standards. Estimated fetal weight differed significantly by race and ethnicity after 20 weeks. At 39 weeks the 50th percentile estimated fetal weight was 3505 g for white, 3336 g for Hispanic, 3270 g for Asian and 3260 g for Black women. The authors report that a standard based only on the white group would wrongly classify as much as 15% of non-white fetuses as growth restricted (estimated fetal weight below the 5th percentile), and they conclude that race- and ethnicity-specific standards improve precision in evaluating fetal growth. - Category: Description - Evidence stage: Observational - Certainty: Certainty not assessed - Applies to: Recipient: Fetal; Population: Fetuses of 1737 women (of 2334 recruited) who stayed low risk at birth (uncomplicated pregnancy, no anomalies): non-Hispanic white, non-Hispanic Black, Hispanic and Asian women, self-identified. Women were aged 18 to 40 years with a body mass index of 19.0 to 29.9 kg/m2, healthy lifestyles and living conditions, and a low-risk medical and obstetric history. The women are the people recruited; the fetuses are the people measured.; Care setting: 12 community and perinatal centres; Geography: United States (the abstract says four US racial/ethnic groups and does not name states); Life stage: Pregnancy; women were screened at 8 weeks 0 days to 13 weeks 6 days, then followed with scheduled ultrasound; Gestational age: 8 weeks 0 days (56 days) to 13 weeks 6 days (97 days), measured at enrolment; Postnatal age: Not reported; Follow-up: Women were randomized among 4 ultrasonography schedules for longitudinal fetal measurement; 92% of recruited women completed the protocol - Limitations: The four groups are the women's self-identified US racial and ethnic categories, and the study is limited to healthy, low-risk women aged 18 to 40 with a body mass index of 19.0 to 29.9. The abstract tests precision of classification by size; it does not test whether using group-specific charts changes outcomes for babies. The three-standards review (see the growth standard disagreement page) notes that the NICHD, INTERGROWTH-21st and WHO charts give different percentiles. Only the abstract was read. - Last checked: 2026-10-14 - Sources: 1. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, STUDY DESIGN, sentence 1. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 2. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, STUDY DESIGN, sentence 2. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 3. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, STUDY DESIGN, sentence 6, fragment 1 of 2. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 4. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, STUDY DESIGN, sentence 6, fragment 2 of 2. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 5. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, RESULTS, sentence 1. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 6. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, RESULTS, sentence 2, fragment 1 of 3. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 7. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, RESULTS, sentence 2, fragment 2 of 3. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 8. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, RESULTS, sentence 2, fragment 3 of 3. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 9. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, RESULTS, sentence 4. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. 10. Supports: Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies (Publication, edition PubMed record (abstract and bibliographic data) from NCBI E-utilities, retrieved 2026-10-14. The full text and the version of record were not read.) Locator: Abstract, CONCLUSION, sentence 2. Retrieved 2026-10-14T18:18:27Z. Source state: Current. Snapshot hash: decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81. How it applies: PubMed abstract. ## Connected pages - Builds racial and ethnic fetal growth standards: Fetal development (`maternal:fetal-development`) - Funder (NICHD contracts in the PubMed grant list): Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) (`maternal:nichd`) ## Provenance Content hash: 25d5675c973a1d68066ce1375c2168d02d9283b106c288c858ef751830369a80 Last substantive edit: 2026-10-14 Evidence last checked: 2026-10-14