Birth-weight-for-gestational-age patterns by race, sex, and parity in the United States population

doi:10.1016/0029-7844(95)00142-E

Obstetrics & Gynecology

Volume 86, Issue 2, August 1995, Pages 200-208

https://doi.org/10.1016/0029-7844(95)00142-E Get rights and content

Objectives: To describe birth-weight-for-gestational-age patterns by race, sex, and parity in the United States population, and to discuss the measurements of gestational age by different methods, the pitfalls of each method, and the potential effects of the errors on birth-weight-forgestational-age curves.

Methods: We used the computerized certificates of live births from the entire population in 1989, consisting of more than four million infants born to residents of the United States. Gestational age was based on the date of the last menstrual period (IMP) modified by the clinical estimate in those situations in which normal distribution of birth weight does not apply. Birth weights for the tenth, 25th, 50th, 75th, and 90th percentiles were calculated by each gestational age and by race, sex, and parity.

Results: Eight sets of smoothed birth-weight-forgestational-age curves were created for black-white, malefemale, and primipara-multipara comparisons in sequence. Compared with previous major curves, our curves were closer to those in which the gestational age was derived from the IMP. There were marked differences observed between our curves and those in which the gestational age was based on ultrasound estimation.

Conclusion: In the measurement of gestational age, the IMP may produce misclassification of gestational age, thereby elevating birth weight percentiles in preteen births and lowering birth weight percentiles in postterm births. However, ultrasound estimation is likely to create a differential misclassification of gestational age, which exerts the opposite effect of lowering birth weight percentiles early in gestation and increasing the percentiles late in gestation.

References (25)

WE Brenner et al.
A standard of fetal growth for the United States of America
Am J Obstet Gynecol
(1976)
RL Goldenberg et al.
Intrauterine growth retardation: Standards for diagnosis
Am J Obstet Gynecol
(1989)
IS Fraser et al.
Fertility following discontinuation of different methods of fertility control
Contraception
(1982)
FH McLean et al.
Postterm infants: Too big or too small?
Am J Obstet Gynecol
(1991)
RL Goldenberg et al.
Prematurity, postdates, and growth retardation: The influence of use of ultrasonography on reported gestational age
Am J Obstet Gynecol
(1989)
L Dubowitz et al.
Clinical assessment of gestational age in the newborn infant
J Pediatr
(1970)
JL Ballard et al.
A simplified score for assessment of fetal maturation of newly born infants
J Pediatr
(1979)
JL Ballard et al.
New Ballard score, expanded to include extremely premature infants
J Pediatr
(1991)
GR Alexander et al.
Validity of postnatal assessments of gestational age: A comparison of the method of Ballard et al. and early ultrasonography
Am J Obstet Gynecol
(1992)
LO Lubchenco et al.
Intrauterine growth as estimated from liveborn birth-weight data at 24 to 42 weeks of gestation
Pediatrics
(1963)

RL Williams et al.

Fetal growth and prenatal viability in California

Obstet Gynecol

(1982)

S Taffel et al.

A method of imputing length of gestation on birth certificates

Cited by (266)

Folic Acid Intake, Fetal Brain Growth, and Maternal Smoking in Pregnancy: A Randomized Controlled Trial
2019, Current Developments in Nutrition
Folic acid supplementation during pregnancy plays an important role in fetal growth and development. To our knowledge, no experimental study has examined the effect of folic acid on fetal brain growth in women who smoke cigarettes during pregnancy.
The aim of this study was to investigate the efficacy of higher-dose compared with standard-dose folic acid supplementation on prenatal fetal brain growth, measured by head circumference, brain weight, and brain-body weight ratio (BBR).
In this randomly assigned, double-blind, controlled clinical trial, we recruited 345 smoking pregnant women attending a community health center in Tampa, FL between 2010 and 2014. Participants were randomly assigned in a 1:1 ratio to receive either 0.8 mg folic acid/d (standard of care at the study center) or 4 mg folic acid/d (higher strength). Participants were also enrolled in a smoking cessation program. A 2-level linear growth model was used to assess treatment effect and factors that predict intrauterine growth in head circumference over time. Multiple linear regression analyses were conducted to estimate the effect of higher-strength folic acid on head circumference at birth, fetal brain weight, and fetal BBRs.
Mothers who received the higher dose of folic acid had infants with a 1.18 mm larger mean head circumference compared with infants born to mothers who received the standard dose, but this difference was not statistically significant (P = 0.2762). Higher-dose folic acid also had no significant effect on brain weight. The BBR of infants of mothers who received higher-dose folic acid was, however, 0.33 percentage points lower than that for infants of mothers who received the standard dose of folic acid (P = 0.044).
Infants of smokers in pregnancy may benefit from higher-strength maternal folic acid supplementation. We noted a decrease in the proportion of infants with impaired BBR among those on higher-dose folic acid. This trial was registered at clinicaltrials.gov as NCT01248260.
A new customized fetal growth standard for African American women: the PRB/NICHD Detroit study
2018, American Journal of Obstetrics and Gynecology
Citation Excerpt :
Considering the multiple differences in the design of the 4 standards compared herein, such as the population on which they were based (homogenous vs multiethnic), the type of data they were derived from (birthweight vs fetal weight), the analytical assumptions they relied on, and the factors these standards were customized for (ethnicity or fetal sex only vs fully customized), this study suggests that customization by the same set of covariates is key for the reproducibility of growth assessment. This study confirms previous observations that maternal ethnicity, height, weight, and parity and fetal sex are factors affecting birthweight and/or fetal growth;76-78 hence, they should be considered when defining fetal growth potential.72,79 Customization of growth charts is commonly performed by assuming a proportionally constant effect of covariates during gestation, and we found that, indeed, this assumption holds for genetically determined (fetal sex) or transmissible (height) traits.
The assessment of fetal growth disorders requires a standard. Current nomograms for the assessment of fetal growth in African American women have been derived either from neonatal (rather than fetal) biometry data or have not been customized for maternal ethnicity, weight, height, and parity and fetal sex.
We sought to (1) develop a new customized fetal growth standard for African American mothers; and (2) compare such a standard to 3 existing standards for the classification of fetuses as small (SGA) or large (LGA) for gestational age.
A retrospective cohort study included 4183 women (4001 African American and 182 Caucasian) from the Detroit metropolitan area who underwent ultrasound examinations between 14-40 weeks of gestation (the median number of scans per pregnancy was 5, interquartile range 3-7) and for whom relevant covariate data were available. Longitudinal quantile regression was used to build models defining the “normal” estimated fetal weight (EFW) centiles for gestational age in African American women, adjusted for maternal height, weight, and parity and fetal sex, and excluding pathologic factors with a significant effect on fetal weight. The resulting Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (hereinafter, PRB/NICHD) growth standard was compared to 3 other existing standards--the customized gestation-related optimal weight (GROW) standard; the Eunice Kennedy Shriver National Institute of Child Health and Human Development (hereinafter, NICHD) African American standard; and the multinational World Health Organization (WHO) standard--utilized to screen fetuses for SGA (<10th centile) or LGA (>90th centile) based on the last available ultrasound examination for each pregnancy.
First, the mean birthweight at 40 weeks was 133 g higher for neonates born to Caucasian than to African American mothers and 150 g higher for male than female neonates; maternal weight, height, and parity had a positive effect on birthweight. Second, analysis of longitudinal EFW revealed the following features of fetal growth: (1) all weight centiles were about 2% higher for male than for female fetuses; (2) maternal height had a positive effect on EFW, with larger fetuses being affected more (2% increase in the 95th centile of weight for each 10-cm increase in height); and (3) maternal weight and parity had a positive effect on EFW that increased with gestation and varied among the weight centiles. Third, the screen-positive rate for SGA was 7.2% for the NICHD African American standard, 12.3% for the GROW standard, 13% for the WHO standard customized by fetal sex, and 14.4% for the PRB/NICHD customized standard. For all standards, the screen-positive rate for SGA was at least 2-fold higher among fetuses delivered preterm than at term. Fourth, the screen-positive rate for LGA was 8.7% for the GROW standard, 9.2% for the PRB/NICHD customized standard, 10.8% for the WHO standard customized by fetal sex, and 12.3% for the NICHD African American standard. Finally, the highest overall agreement among standards was between the GROW and PRB/NICHD customized standards (Cohen's interrater agreement, kappa = 0.85).
We developed a novel customized PRB/NICHD fetal growth standard from fetal data in an African American population without assuming proportionality of the effects of covariates, and without assuming that these effects are equal on all centiles of weight; we also provide an easy-to-use centile calculator. This standard classified more fetuses as being at risk for SGA compared to existing standards, especially among fetuses delivered preterm, but classified about the same number of LGA. The comparison among the 4 growth standards also revealed that the most important factor determining agreement among standards is whether they account for the same factors known to affect fetal growth.
New birthweight charts according to parity and type of delivery for the Spanish population
2017, Gaceta Sanitaria
Birthweight by gestational age charts enable fetal growth to be evaluated in a specific population. Given that maternal profile and obstetric practice have undergone a remarkable change over the past few decades in Spain, this paper presents new Spanish reference percentile charts stratified by gender, parity and type of delivery. They have been prepared with data from the 2010–2014 period of the Spanish Birth Statistics Bulletin.
Reference charts have been prepared using the LMS method, corresponding to 1,428,769 single, live births born to Spanish mothers. Percentile values and mean birth weight are compared among newborns according to gender, parity and type of delivery.
Newborns to primiparous mothers show significantly lower birthweight than those born to multiparous mothers (p < 0.036). Caesarean section was associated with a substantially lower birthweight in preterm births (p < 0.048), and with a substantially higher birthweight for full-term deliveries (p < 0.030). Prevalence of small for gestational age is significantly higher in newborns born by Caesarean section, both in primiparous (p < 0.08) and multiparous mothers (p < 0.027) and, conversely, the prevalence of large for gestational age among full-term births is again greater both in primiparous (p < 0.035) and in multiparous mothers (p < 0.007).
Results support the consideration of establishing parity and type of delivery-specific birthweight references. These new charts enable a better evaluation of the impact of the demographic, reproductive and obstetric trends currently in Spain on fetal growth.
Las tablas de peso al nacer por edad gestacional permiten evaluar el crecimiento fetal en una población específica. Dado que el perfil materno y la práctica obstétrica han experimentado un sustancial cambio en las últimas décadas en España, este trabajo propone nuevas tablas de referencia de percentiles estratificadas por sexo, paridad y tipo de parto, elaboradas con los datos del periodo 2010-2014 del Boletín Estadístico de Partos.
Las curvas de referencia han sido elaboradas mediante el método LMS, correspondientes a 1.428.769 nacidos vivos de partos simples y madres españolas. Se comparan los valores por percentiles y la media del peso al nacer, por sexo, paridad y tipo de parto.
Los nacidos de madres primíparas muestran un peso menor que los nacidos de multíparas (p < 0,036). Los nacidos pretérmino por cesárea tienen un peso menor que los nacidos pretérmino por parto vaginal (p < 0,048), mientras que ocurre lo contrario en los nacidos a término (p < 0,030). La prevalencia de nacidos pequeños para la edad gestacional es mayor entre los nacidos por cesárea de madres tanto primíparas (p < 0,08) como multíparas (p < 0,027), y la prevalencia de nacidos grandes para la edad gestacional es mayor entre los nacidos a término de madres tanto primíparas (p < 0,035) como multíparas (p < 0,007).
Los resultados apoyan establecer referencias de peso al nacer por paridad y tipo de parto. Estas nuevas curvas permiten una mejor evaluación del impacto de las actuales tendencias demográficas, reproductivas y obstétricas en España sobre el crecimiento fetal.
Birth-weight charts and immigrant populations: A critical review
2016, Best Practice and Research: Clinical Obstetrics and Gynaecology
There is an increasing body of literature focusing on differences in newborn size between different population subgroups defined by racial, ethnic, and immigration status. The interpretation of these differences as pathological or as merely reflecting normal variability is not straightforward and may have consequences for the provision of obstetric and neonatal care to minority populations. In this review, we critically assess some methodological issues affecting the assessment of newborn size and their potential implications for minority populations. In particular, we discuss the pros and cons of different types of newborn birth-weight (BW) charts (i.e., single local population-based references, minority-specific references, and a single international standard) to determine abnormal newborn size, with emphasis on immigrant populations. We conclude that size alone is not enough to inform clinical decisions and that all newborn size charts should be used as screening tools, not as diagnostic tools. Parental minority status may be regarded as a marker and used to further inquire about individual risk factors, particularly among immigrants who may not have a complete medical history in the new country. Finally, we outline areas for further research and recommendations for clinical practice.
Singleton birthweight by gestational age following in vitro fertilization in the United States
2016, American Journal of Obstetrics and Gynecology
Citation Excerpt :
After excluding 3474 records (3.58%) for 1 or more of the reasons listed previously, 93,443 IVF singleton births between 24 and 42 completed weeks of gestation were included for analysis. A variety of methods have been used to exclude outliers in large data sets because of errors in recording gestational age or birthweight.1,17-29 In this study, the method of Tukey27 was chosen because of its applicability of more objective ways to identify outliers and its wide use in publications, including most recently in comparison of Australian and New Zealand IVF birthweights by gestational week with Australian National birthweights.26,28
Assisted reproductive technology has been reported to account for a disproportionate higher number of low birthweight infants, even in singleton births. Low birthweight infants occur from preterm birth, decreased intrauterine growth, or both. It is unclear whether infants conceived by in vitro fertilization (IVF) have a reduced intrauterine growth rate or intrauterine growth restriction. Growth-restricted newborns have higher perinatal morbidity and are at increased risk for adult-onset illnesses. To date, there are no national standards for birthweight percentiles by gestational week, allowing for fetal growth assessment of singletons conceived by assisted reproductive technology in the United States.
The objective of the study was to establish US singleton IVF reference standards using birthweight percentiles by gestational age for singleton live births resulting from IVF in the United States.
We studied birthweight by completed weeks of gestation for 93,443 singleton IVF births reported to the Society for Assisted Reproductive Technologies, 2006–2010. The third to 97th birthweight percentiles per completed week of gestation for weeks between 24 and 42 were calculated and were compared with recently published birthweight percentiles by gestational age for 3,812,730 US singleton births in 2011.
Smoothed birthweight for gestational age charts and curves were created for all US IVF singletons and female-male singletons from 24 to 42 weeks. Over the span of 31–41 weeks of gestation, the 10th, 50th, and 90th birthweight percentile values of IVF singletons were comparable with recently published birthweight percentile values of US singletons. At 40 completed weeks of gestation, the 10th, 50th, and 90th birthweight percentiles of all IVF singletons were 3078, 3506, and 4053 g, as compared with corresponding 3005, 3499, and 4057 g of US singletons. The 10th, 50th, and 90th birthweight percentile values for female and male IVF singletons were also comparable with US female and male singletons.
Birthweight percentiles per completed week of gestation of IVF and US singletons are approximately equal from 31 until 41 completed weeks, suggesting that intrauterine growth is not reduced in IVF singleton infants.
Macrosomia is associated with overweight in childhood: A follow-back of a cohort established in the early years of the obesity epidemic
2023, Reproductive and Developmental Medicine

View all citing articles on Scopus

View full text

Birth-weight-for-gestational-age patterns by race, sex, and parity in the United States population

Am J Obstet Gynecol

Am J Obstet Gynecol

Contraception

Am J Obstet Gynecol

Am J Obstet Gynecol

J Pediatr

J Pediatr

J Pediatr

Am J Obstet Gynecol

Intrauterine growth as estimated from liveborn birth-weight data at 24 to 42 weeks of gestation

Pediatrics

Fetal growth and prenatal viability in California

Obstet Gynecol

A method of imputing length of gestation on birth certificates