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Improved method for revising the Israel birthweight references
Lisa Rubin1, Ziona Haklai2, Shaul Dollberg3
1School of Public Health, University of Haifa, Haifa, Israel.
Insights
This study established Israel-specific birthweight references by gestational age, finding differences in singleton and multiple births. Periodic updates are crucial for accurate fetal health assessment.
Area of Science:
- Obstetrics and Gynecology
- Neonatal Health
- Public Health
Background:
- Birthweight is a key indicator of fetal health and development.
- Standardized birthweight charts are essential for clinical assessment, but population-specific data is needed due to variations in growth.
- Categorizing infants as small or large for gestational age has significant clinical implications.
Purpose of the Study:
- To establish a population-based reference for birthweight by gestational age in Israel.
- To stratify these references by singleton/multiple births and gender.
- To provide updated local data for accurate fetal growth assessment.
Main Methods:
- Utilized data from the Ministry of Health Birth Registry (2010-2019).
- Excluded implausible birthweight and gestational age values using visual mapping and interquartile range criteria.
- Analyzed 1,689,696 live births, stratifying by singleton/multiple births and gender.
Main Results:
- Mean birthweight for singletons (3251g) was significantly higher than for multiples (2304g).
- Birthweight differences between singletons and multiples emerged around 30-31 weeks of gestation.
- Singleton birthweight increase plateaued after 42 weeks, with lower weights for those born after 43 weeks.
Conclusions:
- Improved data validation allowed analysis of 96% of births, enhancing reference accuracy.
- The study identified shifts in the distribution of lower and higher birthweight percentiles compared to previous references.
- Regular updates of national growth curves are vital for reflecting current population data and ensuring clinical relevance.
Objectives:
Birthweight is often used as an indicator of fetal health. Categorization of infants as small or large for gestational age has clinical significance. Due to growth differences between countries, it is important to have local reference data. The aim of the study was to describe an Israel population-based reference of birthweight by gestational age stratified for singletons/multiple births and gender.
Methods:
Data on birthweight and gestational age were obtained for the years 2010-2019 from the Ministry of Health Birth Registry. Implausible birthweight and gestational age values were excluded in a two step process. First, overtly implausible values were excluded using visual mapping. Then, infants whose birthweight was below or above the fifth interquartile range for each completed week were excluded.
Results:
During the 10-year period there were 1,761,884 infants delivered in Israel; 1,689,696 were included in the analysis. 4.4% of the live born infants were from multiple births. The mean birthweight of singletons (3251 g) was 947 ± 4 g higher than that of multiples (2304 g). The birthweight of the male multiple births began to differ from that of the singletons at 30 weeks; female multiple births began to deviate at 31 weeks. The increase in birthweight of singletons leveled after 42 weeks and those born after 43 weeks weighed less than infants born earlier. Comparison of the curves for singletons from the present study to those reported for the years 1993-2001 reveal a similar median but significant differences in the distribution of lower and higher percentiles.
Conclusions:
Improved data collection and validation permitted inclusion of 96% of births for analysis. Use of interquartile range distribution to exclude values of birthweight/gestational age that were implausible improved validity. Compared to curves reported previously, changes were found in the distribution of birthweights for the upper and lower percentiles. Periodic updates of growth curve references are important.
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