The National Standard for Normal Fetal Growth

March 14, 2022 updated by: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Normal fetal growth is a critical component of a healthy pregnancy and the long-term health of the offspring. Pivotal to understanding the dynamics of human fetal growth and to defining normal and abnormal fetal growth is the development of standards for fetal growth. The study's purpose was to establish standards for normal fetal growth and size for gestational age for 4 racial/ethnic groups of pregnant women with the eventual creation of individualized standards for fetal growth and improvements in fetal weight estimation. These data for a contemporary cohort of pregnant women should provide data for clinical management.

Study Overview

Status

Completed

Conditions

Detailed Description

Summary and aims:

Normal fetal growth is a critical component of a healthy pregnancy and the long-term health of the offspring. Pivotal to understanding the dynamics of human fetal growth and to defining normal and abnormal fetal growth is the development of standards for fetal anthropometric parameters measured longitudinally throughout gestation, which, in turn, can be used to develop interval velocity curves and customized for genetic and physiological factors. We propose to conduct a multi-center prospective observational study (1) to establish a standard for normal fetal growth (velocity) and size for gestational age in the U.S. population; (2) to create an individualized standard for fetal growth potential; and (3) to improve accuracy of fetal weight estimation.

Eligibility:

• Healthy, low-risk pregnant women (both obese and nonobese) between the ages of 18 and 40 from each of the following four self-identified race/ethnicity backgrounds: African American, Asian, Caucasian, and Hispanic.

Design:

  • Observational cohort design where pregnant women are recruited prior to 13 weeks gestation and followed throughout pregnancy and delivery for women having livebirths.
  • After a sonogram at enrollment (10-13 weeks), women were randomized to receive sonograms according to one of the following four schedules: schedule A: 16, 24, 30, 34, and 38 weeks; schedule B: 18, 26, 31, 35, and 39 weeks; schedule C: 20, 28, 32, 36, and 40 weeks; schedule D: 22, 29, 33, 37, and 41 weeks.
  • An enrollment interview was followed by depression screening, physical activity, anthropometric assessment and ultrasonology screening for measurement of fetal growth, and at each of the 5 subsequent visits.
  • Uterine artery and fetal Doppler studies at selected gestational weeks.
  • Women were asked to provide blood samples at enrollment and at follow-up visits at 16-22 weeks, 24-29 weeks, and 34-37 weeks of gestation.
  • Neonatal anthropometry completed for all infants within 12-24 hours after birth.
  • Cord blood, plasma, and placenta samples were collected for a smaller subsample of newborns.
  • Post-study evaluations: Women who were diagnosed with gestational diabetes during pregnancy were asked to return for a follow-up visit 6 weeks after delivery.

Enrollment:

Final recruitment included 2,802 women with singleton pregnancies of which 2,334 were healthy, low-risk women with pre-pregnancy body mass indices (BMI) between 19-29.9 kg/m2. The racial/ethnic distribution of participating women were: Caucasians (n=614), African American (n=611), Hispanics (n=649), and Asians (n=460), and reflects natality characteristics of contemporary U.S. births. An additional 468 obese women (BMI 30-44.9 kg/m2) were also recruited.

Quality Control:

The quality of the ultrasound measures was guaranteed by implementation of: (1) a comprehensive quality control protocol for ante hoc training and credentialing of all site sonographers, developed by the sonology center at Columbia University, and (2) a rigorous protocol for post hoc quality control, whereby a random sample of all scans, stratified by clinical site and visit, was re-measured for accuracy and reliability.

Study Type

Observational

Enrollment (Actual)

2802

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States
        • University of Alabama
    • California
      • Fountain Valley, California, United States, 92708
        • Fountain Valley Regional Hospital
      • Long Beach, California, United States, 90806
        • University of California-Long Beach
      • Orange, California, United States, 92668
        • University of California, Irvine Medical Center
    • Delaware
      • Newark, Delaware, United States
        • Christiana Care Health Services
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Northwestern University
    • New Jersey
      • New Brunswick, New Jersey, United States, 08901
        • Saint Peters University Hospital
    • New York
      • Flushing, New York, United States, 11355
        • New York Presbyterian Healthcare System
      • New York, New York, United States, 10032-3784
        • Columbia University
    • Rhode Island
      • Providence, Rhode Island, United States, 02905
        • Women and Infants
    • South Carolina
      • Charleston, South Carolina, United States
        • Medical University of South Carolina

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Sampling Method

Non-Probability Sample

Study Population

Women with singleton gestations (n=2,802) were enrolled from 12 U.S. clinical centers. Women were enrolled between 8w0d and 13w6d gestation, as measured by last menstrual period dating consistent with obstetrical ultrasonology.

Description

  • INCLUSION CRITERIA:
  • Singleton, viable pregnancy
  • 8 plus 0 - 13 plus 6 weeks of gestation
  • Maternal age 18 - 40 years
  • BMI 19.0 -29.9kg/m(2) for low risk group; BMI 30.0 - 45.0kg/m(2) for obese group
  • Firm LMP
  • LMP-date and ultrasound date match within 5 days for gestation estimates between 8 weeks + 0 days and 10 weeks + 6 days, 6 days for those between 11 weeks + 0 days and 12 weeks + 6 days, and 7 days for estimates between 13 weeks + 0 days and 13 weeks + 6 days
  • No confirmed or suspected fetal congenital structural or chromosomal anomalies
  • Expect to deliver at one of the participating hospitals
  • No previous participation in the NICHD Fetal Growth Study

EXCLUSION CRITERIA:

  • Smoked cigarettes or used illicit drugs in the six months
  • Used illicit drugs in the past year
  • Having at least 1 alcoholic drink per day
  • Conception by ovulation stimulation drugs or assisted reproductive technology
  • Chronic hypertension or renal disease under medical supervision
  • Asthma requiring weekly medication
  • Diabetes mellitus
  • Thyroid disease under medical supervision
  • Autoimmune disorder (rheumatoid arthritis, lupus, antiphospholipid antibody syndrome,scleroderma)
  • Hematologic disorders (chronic anemia, sickle cell disease thrombocytopenia coagulation defects, thrombophilia)
  • Cancer
  • HIV or AIDS
  • Epilepsy or seizure on medication or occurrence within 2 years
  • Psychiatric disorder (bipolar disorder, depression, anxiety disorder currently requiring medication)
  • Current anorexia nervosa or bulimia
  • Previous severe preclampsia, eclampsia, HELLP syndrome
  • Previous stillbirth or neonatal death
  • Previous very preterm birth (less than 34 weeks)
  • Previous low birthweight (less than 2,500 g)
  • Previous macrosomia (greater than or equal to 4,500 g)

The following criteria apply only to obese women only:

  • Chronic hypertension or high blood pressure requiring two or more medications
  • Diabetes while not pregnant
  • Chronic renal disease under medical supervision
  • Autoimmune disease (rheumatoid arthritis, lupus, antiphospholipid antibody syndrome, scleroderma)
  • Psychiatric disorder (bipolar disorder, depression, anxiety disorder currently requiring medication)
  • Cancer (currently receiving treatment)
  • HIV or AIDS

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Low risk singleton cohort
Women with singleton gestations were enrolled between 8w0d and 13w6d and followed up to nine months (2009-2013) in this prospective cohort study. A sub-set of women with and without gestational diabetes were followed up to 6 weeks postpartum. Enrollment was based upon a predefined set of criteria including medical/reproductive history and pre-pregnancy body mass index. Women with a body mass index between 19.0-29.9 kg/m2 were in the low-risk cohort.
Obese cohort
Women with singleton gestations were enrolled between 8w0d and 13w6d and followed up to nine months (2009-2013) in this prospective cohort study. A sub-set of women with and without gestational diabetes were followed up to 6 weeks postpartum. Enrollment was based upon a predefined set of criteria including medical/reproductive history and pre-pregnancy body mass index. Women with a body mass index between 30.0-44.9 kg/m2 were in the obese cohort.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Establish a standard for normal fetal growth (velocity) and size for gestational age in the U.S. population.
Time Frame: 3 years

Fetal growth trajectories were created using 2-D ultrasound fetal biometry including biparietal diameter, head circumference, humerus length, abdominal circumference, and femur length using standardized protocols. Estimated fetal weight (EFW) was calculated.

Fetal growth trajectories were created using linear mixed models with cubic splines for estimating racial/ethnic specific fetal growth curves for size, methods that accounted for the variation across individual fetuses. For EFW and each individual anthropometric parameter, we tested for overall differences in the racial/ethnic-specific curves using a likelihood-ratio test. When the global test was significant (<.05 level), we tested for week-specific differences by race/ethnicity using Wald tests at each week of gestation. These tests were conducted on the estimated curves with and without adjustment for maternal characteristics.

A fetal growth velocity standard by maternal race/ethnicity was also created.
3 years
Create an individualized standard for fetal growth potential.
Individualized and customized fetal growth models will be created using two- dimensional ultrasound measures. Individualized or customized definitions of small for gestational age or large for gestational age will be compared to the NICHD Fetal Growth Study singleton standard cut-points of 10th and 90th percentiles, respectively, to see if they improve detection of maternal and neonatal health outcomes.
Improve accuracy of fetal weight estimation.
Since the last ultrasound exam is scheduled at term, it was expected that many women would deliver within 3 days after the last ultrasound exam. A formula (or formulas) to estimate fetal weight will be created using a multiple linear regression to include not only the 2-D and 3-D sonographic measurements but also factors such as maternal height and weight, sex of the fetus, and glucose challenge test result. We will identify a formula that provides the best estimate of fetal weight, and apply that formula to a validation group. If the sample size allows, we will randomly split the whole cohort into two groups: one group for testing and the other for validation. If the statistical power is insufficient for splitting, we will use cross-validation.

Secondary Outcome Measures

Outcome Measure
Measure Description
Construct an individualized standard for fundal height.
We will reevaluate the sensitivity and specificity of the current approach to using fundal height to monitor fetal growth. We will produce an individualized standard for fundal height. We will compare the new standard with the current approach with regard to true positive and true negative values.
Collect blood samples for an etiology study of gestational diabetes and a prediction study of fetal growth restriction and/or overgrowth.
Blood samples were collected at enrollment, visit 1, visit 2 and visit 4.
Collect placental tissues and cord blood in selected cases and controls for studies on the etiology of idiopathic fetal growth restriction.
Placental tissue and cord blood at delivery were collected in selected IUGR cases and controls. Placental DNA samples were genotyped. DNA methylation and RNA were quantified.
Collect dietary intake data to study the association between nutrition and fetal growth.
Food frequency questionnaire was collected at enrollment and 24-h dietary recall at visit 1, visit 2, visit 3, and visit 4.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

May 19, 2009

Primary Completion (ACTUAL)

August 25, 2013

Study Completion (ACTUAL)

August 25, 2013

Study Registration Dates

First Submitted

May 30, 2009

First Submitted That Met QC Criteria

May 30, 2009

First Posted (ESTIMATE)

June 3, 2009

Study Record Updates

Last Update Posted (ACTUAL)

March 29, 2022

Last Update Submitted That Met QC Criteria

March 14, 2022

Last Verified

March 1, 2022

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 999909152
  • 09-CH-N152

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Pregnancy and postpartum data will be made accessible in documented repositories and electronic archives after completion of the studies' analytical phases.

IPD Sharing Time Frame

After completion of the studies' analytical phases.

IPD Sharing Access Criteria

The data, along with a set of guidelines for researchers applying for the data, will be posted to a data-sharing site. All requests for data must include a short protocol with a specific research question and a plan for analysis. Before receiving any analytical file, all users must complete a Data Use Agreement form.

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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