Birthweights at Term on Rise globally reveals Comprehensive Systematic Review of 183 Million Births

The quality of the included studies was evaluated using the Dufault and Klar checklist modified by Betran et al. The effects of time (years) and geographical origins were also examined. Subgroup analyses focused on national data sources and data collected from 1950 onward.

The researchers reported the following findings:

· Among 6447 reviewed articles, 29 met the criteria, reporting mean birthweight data from over 183 million infants worldwide.

· Most studies were hospital-based (48.3%), 44.8% used national data, and a minority used municipality, community, or regional data (6.9%).

· Geographically, North America (31.0%) had the highest representation, followed by Asia and Europe (27.6% each), and South America and Oceania (6.9% each).

· The univariate linear regression model (Model 1) revealed a significant increase in mean birthweight at term over time (4.74 g/y).

· Model 2, incorporating continental dummy variables into the first model, confirmed this trend (3.85 g/y).

· Model 3, focusing on available national data, did not find a significant relationship.

· Model 4 narrowed its focus on records from 1950 onward, reporting a robust annual increase of 7.26 g/y.

· Model 5, adjusting for the number of participants included in each study, reported a conclusive mean term birthweight increase of 1.46 g/y.

Limitations include study quality variations, data sparsity, and data source diversity, underscoring the need for future research to use precise gestational age distinctions and predetermined time frames to get a deeper understanding of this trend and its implications for child and maternal 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 Mar 7:S0002-9378(24)00431-9. doi: 10.1016/j.ajog.2024.03.002. Epub ahead of print. PMID: 38460833.