Recent presented research paper, authored by Giulia Bonanni, Chiara Airoldi, and Vincenzo Berghella, aims to assess global trends in mean birthweights at term as reported in peer-reviewed literature. The study conducted a systematic review of literature on this subject and included data from over 183 million births worldwide.
The authors mention that there have been significant changes in maternal and fetal health in recent decades, influencing birthweight dynamics. While genetic factors and in utero influences are primary contributors to birthweight, additional predictors like age, parity, and maternal anthropometry have been identified. The study used electronic searches in PubMed, Embase, and Web of Science without any language or geographic restrictions, including ecological and observational studies reporting mean birthweight at term as a continuous numerical variable over time. The study retrieved 6447 articles and ultimately assessed 29 studies meeting the inclusion criteria.

The majority of the selected studies were hospital-based, while 44.8% utilized national data, and a small proportion used municipality, community, or regional data. Geographically, North America had the highest representation, followed by Asia, Europe, South America, and Oceania. The univariate and multivariate linear models revealed a significant increase in mean birthweight at term over time. The regression model focusing on records from 1950 onward reported a robust annual increase in mean birthweight. Subgroup analyses were also performed to focus on national data sources and data collected from 1950 onward, both of which yielded significant relationships.
The authors acknowledge limitations in the study, such as variations in study quality, the diversity of data sources, and sample size discrepancies. The study also mentions the need for future research to use precise gestational age distinctions and predetermined time frames to gain a deeper understanding of the trend in birthweight and its implications for maternal and child health. The authors also provide a detailed discussion of the implications of their findings, including the impact of changing birthweights on childbirth practices and the rising rate of cesarean delivery. They highlight the need for ongoing research to further understand this trend, address the study limitations, and provide a more nuanced perspective on the implications for maternal and child health.

Key Points
1. The research paper aims to assess global trends in mean birthweights at term by conducting a systematic review of literature on the subject, including data from over 183 million births worldwide. The authors note the significant changes in maternal and fetal health in recent decades and the influence on birthweight dynamics by genetic factors, in utero influences, and additional predictors like age, parity, and maternal anthropometry.
2. The study used electronic searches in PubMed, Embase, and Web of Science to retrieve 6447 articles and ultimately assessed 29 studies meeting inclusion criteria. These studies were primarily hospital-based, with 44.8% utilizing national data and a small proportion using municipality, community, or regional data. Geographically, North America had the highest representation, followed by Asia, Europe, South America, and Oceania.
3. The univariate and multivariate linear models revealed a significant increase in mean birthweight at term over time, with a robust annual increase reported from 1950 onward. Subgroup analyses focusing on national data sources and data collected from 1950 onward also yielded significant relationships.
4. The study acknowledges limitations such as variations in study quality, diversity of data sources, and sample size discrepancies, highlighting the need for future research to use precise gestational age distinctions and predetermined time frames to gain a better understanding of the trend in birthweight and its implications for maternal and child health.
5. The authors discuss the implications of their findings, including the impact of changing birthweights on childbirth practices and the rising rate of cesarean delivery, and stress the need for ongoing research to further understand this trend and its implications for maternal and child health. 6. In conclusion, the paper provides a comprehensive analysis of global trends in birthweights at term, emphasizing the need for further research to address study limitations and provide a more nuanced perspective on the implications for maternal and child health.
Conclusion
Overall, the study offers a comprehensive analysis of global trends in birthweights at term, exhibiting a robust approach to data analysis and a systematic review of the relevant literature. The study concludes by stressing the need for further research addressing the limitations highlighted in the study and providing a more nuanced perspective on the implications for maternal and child health.
Reference -
Bonanni G, Airoldi C, Berghella V. Birthweights at term have increased globally: insights from a systematic review of 183 million births. Am J Obstet Gynecol. 2024 Oct;231(4):395-407.e4. doi: 10.1016/j.ajog.2024.03.002. Epub 2024 Mar 7. PMID: 38460833.