Comparison of the performance of estimated fetal weight charts for the detection of small‐ and large‐for‐gestational age newborns with adverse outcomes: a French population‐based study

Abstract

Objective To compare the performance of estimated fetal weight (EFW) charts at the third trimester ultrasound for detecting small-and large-for-gestational age (SGA/LGA) newborns with adverse outcomes.Design Nationally representative observational study.Setting French maternity units in 2016.Population 9940 singleton live births with an ultrasound between 30 and 35 weeks of gestation. Methods We compared three prescriptive charts (INTERGROWTH-21st, World Health Organization (WHO), Eunice Kennedy Shriver National Institute of Child Health and Human Development [NICHD]), four descriptive charts (Hadlock, Fetal Medicine Foundation, two French charts) and a French customised growth model (Epop e).Main outcome measures SGA and LGA (birthweights <10th and >90th percentiles) associated with adverse outcomes (low Apgar score, delivery-room resuscitation, neonatal unit admission).Results 2.1% and 1.1% of infants had SGA and LGA and adverse outcomes, respectively. The sensitivity and specificity for detecting Conclusion Marked differences in the performance of descriptive as well as prescriptive EFW charts highlight the importance of evaluating them for their ability to detect high-risk fetuses.

The clinical performance and population health impact of birth weight-for-gestational age indices with regard to adverse neonatal outcomes in term infants

“…Theoretically, such diagnoses could be used as inputs for improving obstetric and neonatal management in conjunction with other markers and pregnancy complications. However, as previous studies have shown 14,15,[23][24][25][26]36 and our study confirms, SGA or LGA diagnosis, when used in isolation without other predictors, performs poorly for predicting SNMM; in other words, the probability of SNMM (or neonatal death) is not materially changed by such a diagnosis. In our study, the expected risk of SNMM changed marginally from 20.2 per 1,000 live births to 23.8, 36.1 and 54.4 per 1,000 live births using a mild (10% increase in odds), moderate (50%) or extreme (100%) definition of SGA among female singletons at 39 weeks' gestation (Table 1).…”

“…The poor performance of SGA and LGA diagnoses in predicting SNMM and neonatal death weakens arguments regarding the superiority of references vs standards. 13,17,[19][20][21][22][23][24]37 For instance, diagnosis of SGA among term births using national references was associated with positive and negative likelihood ratios for perinatal death of 3.2 and 0.77, respectively; this changed the pretest probability of perinatal death to an inconsequential extent (from 1.7 per 1,000 total births to a posttest probability of 5.4 per 1,000 total births). 22 Similarly, the sensitivity, specificity, likelihood ratios and PAFs for neonatal morbidity associated with an SGA diagnosis based on customized charts was of limited utility at both the individual and population level (sensitivity and PAF for neonatal seizures 14.1% and 4.3%, respectively; sensitivity and PAF for glucose instability 22.9% and 14.0%, respectively).…”

“…Although the newly created normative/prescriptive Intergrowth 21 st Project and World Health Organization (WHO) birth weight-for-gestational age standards [1][2][3][4] represent a conceptual departure from previous descriptive, population-based references [5][6][7][8][9][10][11] and offer several theoretical advantages, studies comparing existing references and the new standards have not succeeded in establishing a preferred method for identifying SGA and LGA infants. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] One study, 22 which contrasted the Intergrowth standard with population-based references from 15 European countries, showed that infants classified as AGA by the Intergrowth standard and SGA by the 15 national references had a 2.7-fold higher risk of perinatal death (compared with infants deemed AGA by both). Conversely, infants categorized as LGA by the Intergrowth standard but AGA by the national references were at significantly reduced risk of perinatal death.…”

Predictive value of fetal growth trajectory from 20 weeks of gestation onwards for severe adverse perinatal outcome in low‐risk population: secondary analysis of IRIS study

“…Although it is common practice to use composite outcomes in FGR studies, one might argue that some of these outcomes can be a result of both the condition, i.e. placental insufficiency, and the treatment, which is often provider-initiated (relatively) premature or early term birth 7,8,14,[34][35][36] . We found that the group that experienced a decline in AC and/or EFW of > 50 percentiles had the lowest rate of spontaneous onset of labor and the highest rate of prelabor Cesarean section.…”

Assessing the performance of growth charts: A difficult endeavour

“…We read with great interest the article by Monier et al comparing the performance of different EFW references and standards for the prediction of small and large birth weight infants in France. 1 This is an exciting topic and the authors are to be commended for using a large national database to develop their arguments. We wish to make a number of comments on their analysis.…”