IG-21st reference standards have a high predictive value for antenatal fetal growth monitoring: Study
Fetal growth restriction (FGR), is a common complication of pregnancy that has been associated with a variety of APO (Adverse perinatal outcome). An optimal management and timing of delivery of FGR fetuses improves perinatal outcome. Distribution at a given gestational age. Consequently, a fraction of fetuses are either large for gestational age (LGA) or small for gestational age (SGA) regardless of their growth potential. Currently, fetal-growth disorders at both ends of the spectrum are major problem in obstetrics with APO.
FGR represents the second primary cause of perinatal mortality after prematurity, accounting for 30% of still births, besides determining a higher frequency of preterm births and intrapartum asphyxia. FGR is also associated with neonatal complications and higher incidence of coronary diseases, arterial hypertension and diabetes in adult life have also been reported. Antenatal and postnatal care consist mostly of a series of screening tests of varied complexity, implemented at different levels of care, which together contribute to evaluating the overall health and nutritional status of each pregnant women and new born baby. Objective assessments of fetal and neonatal growth deviations can play a major role in routine clinical care, as well as maternal and neonatal health research.
In affected pregnancies especially those that have not reached term, there is a need to monitor growth more closely to decide if clinical interventions are required. However, international antenatal growth charts analogous to the World Health Organization (WHO) Multicenter Growth Reference Study (MGRS) standards for infants and young children, developed using prescriptive approaching, are not available.
The International Fetal and Newborn Growth Consortium for the 21st century, or INTERGROWTH-21st , is a global, multidisciplinary network of more than 300 researchers and clinicians from 27 institutions in 18 countries worldwide and coordinated from the University of Oxford, dedicated to improving perinatal health globally and committed to reducing the millions of preventable newborn deaths that occur as a result of preterm birth or FGR. They have developed INTERGROWTH-21st Global Perinatal Package which comprises of new, globally-validated standards for fetuses, newborn infants and the postnatal growth period of preterm infants through the INTERGROWTH-21st Project. INTERGROWTH-21st project is the first, population based, large, multi-ethnic, longitudinal, fetal growth standard based on early assessment of gestational age and their reference standards for antenatal fetal growth monitoring are according to the most recent data and globally validated.
A prospective longitudinal study was done on 100 patients visiting outpatient department (OPD) of Department of OBG, SDMCMSH, Dharwad, Karnataka, for regular ante natal care (ANC), booked at 32weeks and one at near term. Fetal biometry measured (CRL-crown rump length, BPD-Biparietal diameter, HC-head circumference, AC-abdominal circumference, FL-femoral length, EFW-estimated fetal weight) were plotted on IG-21st charts and monitored the fetal growth. The neonatal parameters at birth and perinatal outcome were noted.
Ninety six (96%) fetuses had normal growth curves (NGC) for all assessed parameters. Four (4%) had growth curves (GC) for AC and EFW falling below NGC indicating fetal growth restriction (FGR).At birth, all these 4 babies (100%) had LBW indicating that fetal monitoring using IG-21st had accurately identified all (100%) fetuses at risk for FGR and AC and EFW were better parameters for assessment of FGR compared to HC, BPD and FL.), but were AGA (appropriate for gestational age); thus, indicating applicability of IG-21s
This study showed that the INTERGROWTH-21st reference standard charts developed using the same methods and conceptual approach as the WHO-MGRS standards for infants and young children, which are claimed to be based on most recent data and globally validated, are applicable to population for antenatal fetal growth monitoring. It was effective in identifying fetal growth restriction in the study population, aiding proper monitoring and timely intervention when needed, thus improving the perinatal outcome. But further studies need to done using larger cohorts and also comparing the efficacy of the INTERGROWTH 21st standards with the customized standards for pregnancies at risk for neonatal SGA and adverse perinatal outcome. Also to validate the applicability of these charts to the Indian population.
Source: Akshitha et al. / Indian Journal of Obstetrics and Gynecology Research 2025;12(3):563–569
