Association Between Maternal Midterm eGFR and Newborn Birthweight: Seiiku Boshi Cohort Study

Akiko Sankoda; Naoko Arata; Yuichiro Yano; Kohei Ogawa; Nagayoshi Umehara; Asako Mito; Seiji Wada; Naho Morisaki; Yushi Ito; Haruhiko Sago; Reiko Horikawa

doi:10.34067/KID.0000001042

Association Between Maternal Midterm eGFR and Newborn Birthweight: Seiiku Boshi Cohort Study

Kidney360. 2025 Dec 18. doi: 10.34067/KID.0000001042. Online ahead of print.

Authors

Akiko Sankoda^{1

2}, Naoko Arata^{1

2}, Yuichiro Yano³, Kohei Ogawa⁴, Nagayoshi Umehara⁴, Asako Mito^{1

2}, Seiji Wada⁴, Naho Morisaki⁵, Yushi Ito⁴, Haruhiko Sago⁴, Reiko Horikawa⁶

Affiliations

¹ Preconception Care Center, Integrated Center for Women's Health, National Center for Child Health and Development, Tokyo, Japan.
² Women's Internal Medicine, Women's Health Center, National Center for Child Health and Development, Tokyo, Japan.
³ Department of general medicine, Juntendo University School of Medicine, Tokyo, Japan.
⁴ Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan.
⁵ Department of Social Medicine, National Research Institute for Child Health and Development, Tokyo, Japan.
⁶ Division of Endocrinology and Metabolism, National Center for Child Health and Development, Tokyo, Japan.

PMID: 41411060
DOI: 10.34067/KID.0000001042

Abstract

Background: Little is known regarding whether renal function during pregnancy among healthy women is associated with pregnancy outcomes. Evidence based on the universal screening of maternal eGFR is lacking. We investigated the association of maternal eGFR during the second trimester with fetal birthweight.

Methods: This prospective birth cohort study includes 1,666 singleton pregnant women (median age 36 years, median BMI 20.0) who had universal screening of eGFR during the second trimester. Participants were categorized into the quartile of eGFR. The 1st quartile group was defined as low eGFR, the 4th quartile group as high eGFR, and the 2nd and 3rd quartile group as reference. The primary outcomes are low birthweight (LBW) and small for gestational age (SGA). Multivariable logistic regression models were used to investigate the association of maternal eGFR and pregnancy outcomes.

Results: As compared to the reference group, the adjusted odds ratios (95% Confidence Intervals [CI]) for LBW and SGA in the low eGFR group were 2.25 (1.48-3.40) and 2.51 (1.63-3.87), respectively, and in the high eGFR group were 0.69 (0.40-1.19) and 0.55 (0.30-1.02), respectively. The adjusted odds ratios of eGFR per SD decrease (95% CI) for LBW and SGA were 1.92 (1.50-2.45) (p=0.013) and 2.07 (1.60-2.68) (p<.001). The prediction models were improved by adding eGFR to the models including covariates; for LBW (C statistics difference, +0.018; 95% CI, -0.004-0.040, net reclassification index (NRI), 0.377; 95% CI, 0.208-0.545, and integrated discrimination improvement (IDI), 0.0135; 95% CI, 0.005-0.022) and for SGA (C statistics difference, +0.041; 95% CI, 0.003-0.080, NRI, 0.408; 95% CI, 0.226-0.591, and IDI, 0.017; 95% CI, 0.009-0.025).

Conclusions: The lower maternal midterm eGFR is associated with LBW and SGA, while the higher eGFR is not. Evaluating midterm eGFR may help identify healthy women at risk of adverse birth outcomes.