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NICHD Fetal Growth Studies

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.

  • Study
  • In this atlas

Overview

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
  • 2,334 women (healthy women with low-risk singleton pregnancies recruited) (enrolled count) (Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies, retrieved )
  • 1,737 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, retrieved )
Sponsor
Not recorded
Registry
Not reported
Started
Not reported
Primary completion
Not reported
Completion
Not reported
Countries
Not reported
Care setting
Not reported
Registry status
Not reported

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.

Arms

Not reported

Findings

No findings are published for this study.

Claims and evidence

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
Eligibility: 3 inclusion criteria; 1 exclusion criterion
Included
  • Aged 18 to 40 years
  • Body mass index 19.0 to 29.9 kg/m2
  • Healthy lifestyles and living conditions; low-risk medical and obstetrical history
Excluded
  • Not stated in the parts of the source that were read.

  • Description Observational Certainty not assessed

    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.

    Applies to Fetal
    • 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.
    • 12 community and perinatal centres
    • United States (the abstract says four US racial/ethnic groups and does not name states)
    • 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 to 13 weeks 6 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
    Certainty method
    Not assessed
    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
    Next evidence check due
    Not scheduled
    Sources and citations (10)

    1. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, STUDY DESIGN, sentence 1
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    2. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, STUDY DESIGN, sentence 2
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    3. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, STUDY DESIGN, sentence 6, fragment 1 of 2
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    4. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, STUDY DESIGN, sentence 6, fragment 2 of 2
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    5. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, RESULTS, sentence 1
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    6. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, RESULTS, sentence 2, fragment 1 of 3
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    7. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, RESULTS, sentence 2, fragment 2 of 3
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    8. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, RESULTS, sentence 2, fragment 3 of 3
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    9. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, RESULTS, sentence 4
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

    10. Supports Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies

      Publication · American journal of obstetrics and gynecology · 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. · DOI: 10.1016/j.ajog.2015.08.032 · PMID: 26410205

      Locator
      Abstract, CONCLUSION, sentence 2
      How it applies
      PubMed abstract.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      decf1a4b9e402325e67b0d610368844218bc41a16919976f9e334a0c389dde81
      Reuse basis
      PubMed record fetched through NCBI E-utilities. Only the hash of the bytes is kept, because publisher copyright may apply to the abstract (https://pubmed.ncbi.nlm.nih.gov/disclaimer/). Short factual quotations under 25 words, with the citation.

Record details

Record id
maternal:nichd-fetal-growth-studies
Content hash
25d5675c973a1d68066ce1375c2168d02d9283b106c288c858ef751830369a80