Agreement Between Self-Reported Pre-Pregnancy Weight and Weight Measured During the First Trimester of Pregnancy: A Comparison of Research and Administrative Data. (29th May 2020)

• Record Type: Journal Article
• Authors: Carrilho, Thais; Rasmussen, Kathleen; Farias, Dayana; Batalha, Monica; Costa, Nathalia; Gonzalez, Mylena; Kac, Gilberto
• Is Part Of: Current developments in nutrition. Volume 4(2020)Supplement 2
• Page Start: 953
• Page End: 953
• Publication Date: 2020-05-29
• Subjects: Nutrition -- Periodicals; Nutritional Physiological Phenomena; Nutrition; Periodicals; Periodicals; Fulltext; Internet Resources; Periodicals; 612.3
• DOI: 10.1093/cdn/nzaa054_025
• Languages: English
• ISSNs: 2475-2991

Abstract

Abstract: Objectives: To assess the agreement between self-reported pre-pregnancy weight (SRPW) and weight measured up to the 6 th, 8 th, and 13 th weeks among Brazilian women in research and administrative datasets. Methods: Data from the Brazilian Maternal and Child Nutrition Consortium (BMCNC) ( n = 5563), with gestational information from the last 30 y in Brazil, and data from the Brazilian Food and Nutrition Surveillance System (SISVAN) from 2008–2018 ( n = 38, 678) were used. The SRPW was compared to the weight measured up to the 6 th, 8 th and 13 th gestational weeks. The analyses were conducted separately for each source of data and, within each, they included a comparison between the mean SRPW and the measured weights; determination of Pearson's, Lin's and intra-class correlation coefficient for the SRPW and the weights measured in first trimester; construction of Bland and Altman plots, and calculation of the Kappa coefficient to assess the impact of using each type of weight on women's pre-pregnancy body mass index (BMI) classification. Results: The mean difference between SRPW and measured weights was <2 kg at all the compared gestational weeks for both the BMCNC and SISVAN datasets and all the coefficients were above 0.90 ( P < 0.001). Bland-Altman plots revealed no systematic differences between the measurements but the differences between those were elevated for some women (>5 kg in ∼16% in the BMCNC and ∼10% in the SISVAN data). The Kappa coefficients revealed high agreement (BMCNC: 0.87, 0.86 and 0.84; SISVAN: 0.80, 0.79 and 0.75, for the 6th, 8th, and 13th weeks, respectively) for pre-pregnancy BMI classification. The difference in the prevalence of women in each BMI category was <5% for both datasets and each gestational week studied, regardless of whether SRPW or first-trimester weight was used to determine BMI. Conclusions: There was a high agreement between SRPW and the weight measured during the 1 st trimester in both research and administrative data. Also, the difference in BMI classification when each weight was used was very low. Thus, the use of SRPW is possible when there is no measured weight at the beginning of pregnancy. This is an advantage, especially in low- and middle-income countries, where many women do not start prenatal care during the first trimester. Funding Sources: Brazilian National Council for Scientific and Technological Development, Bill and Melinda Gates Foundation.