Publication: Variability of urinary creatinine, specific gravity, and osmolality over the course of pregnancy: Implications in exposure assessment among pregnant women
Issued Date
2020-01-01
Resource Type
ISSN
10960953
00139351
00139351
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2-s2.0-85096825969
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Mahidol University
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SCOPUS
Bibliographic Citation
Environmental Research. (2020)
Suggested Citation
Gowoon Lee, Sunmi Kim, Hyunwoong Park, Jeonghwan Lee, Jung Pyo Lee, Younglim Kho, Gyuyeon Choi, Jiwon Park, Suwalee Worakhunpiset, Hyo Bang Moon, Kyungho Choi Variability of urinary creatinine, specific gravity, and osmolality over the course of pregnancy: Implications in exposure assessment among pregnant women. Environmental Research. (2020). doi:10.1016/j.envres.2020.110473 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/60420
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Title
Variability of urinary creatinine, specific gravity, and osmolality over the course of pregnancy: Implications in exposure assessment among pregnant women
Other Contributor(s)
Seoul Metropolitan Government - Seoul National University Borame Medical Center
Eulji University
Hanyang University
Soonchunhyang University, College of Medicine
Seoul National University
Mahidol University
Korea Research Institute Chemical Technology
Seoul National University College of Medicine
Cheongdam Yeon & Nature Obestetrics & Gynecology
Eulji University
Hanyang University
Soonchunhyang University, College of Medicine
Seoul National University
Mahidol University
Korea Research Institute Chemical Technology
Seoul National University College of Medicine
Cheongdam Yeon & Nature Obestetrics & Gynecology
Abstract
© 2020 Elsevier Inc. Due to dilution status of the urine, chemical concentrations measured in spot urine are frequently adjusted using correction factors, such as creatinine, specific gravity (SG), or osmolarity of the urine. Urinary correction factors, however, can be influenced dramatically by physiological changes such as pregnancy. Details about the variation of urine dilution over the course of pregnancy are not well characterized. In the present study, we investigated the variation of urine correction factors over time among the pregnant women of Korea (n = 69) and Thailand (n = 102). Creatinine, SG, and osmolality were determined in the urine samples obtained in each trimester of the participating women, and were compared by sampling time and by nationality. Implication of the variation in these correction factors was studied using phthalate metabolites measured in the urine samples as model chemicals. Urinary correction factors significantly varied across the trimesters especially in Korean pregnant women: urinary creatinine and osmolality were significantly lower in the third trimester (T3) urine than the first trimester (T1) urine. Urinary creatinine and SG of the T3 urine of Korean pregnant women were also significantly lower than those reported from the non-pregnant women who participated in Korean National Environmental Health Survey (KoNEHS) 2015–2017. Among Thai women, however, these correction factors were rather stable across the pregnancy. Differences in ethnicity, or in behavior such as water consumption amount may partly explain the differences. Temporal changes in these urine correction factors influenced the urinary phthalate metabolite concentrations adjusted for dilution, in both Korean and Thai pregnant women. The present observations show that the variations of urinary correction factors should be considered in exposure assessment of urinary chemicals for pregnant women, in order to circumvent potential bias due to physiological changes occurring during pregnancy, and to reduce errors in exposure classification and association.