Association between Maternal Midterm eGFR and Newborn Birth Weight: Seiiku Boshi Cohort Study

Area of Science:

• Obstetrics and Gynecology
• Nephrology
• Perinatal Medicine

Background:

• Maternal renal function during pregnancy is not well understood in relation to fetal outcomes.
• Evidence from universal screening of maternal estimated glomerular filtration rate (eGFR) is limited.
• This study investigates the association between mid-pregnancy eGFR and fetal birthweight.

Purpose of the Study:

• To examine the relationship between maternal eGFR in the second trimester and fetal birthweight.
• To determine if maternal eGFR is associated with adverse pregnancy outcomes like low birthweight (LBW) and small for gestational age (SGA).

Main Methods:

• A prospective birth cohort study of 1,666 singleton pregnant women.
• Maternal eGFR was measured during the second trimester and categorized into quartiles.
• Multivariable logistic regression models analyzed the association between eGFR quartiles and outcomes (LBW, SGA).

Main Results:

• Low maternal eGFR in the second trimester was significantly associated with increased odds of LBW (aOR 2.25) and SGA (aOR 2.51) compared to the reference group.
• High eGFR was not significantly associated with LBW or SGA.
• Each standard deviation decrease in eGFR increased the odds of LBW (aOR 1.92) and SGA (aOR 2.07).
• Adding eGFR to prediction models improved their accuracy for identifying LBW and SGA.

Conclusions:

• Lower maternal eGFR during the second trimester is a risk factor for LBW and SGA in healthy women.
• Higher eGFR is not associated with adverse birth outcomes.
• Midterm eGFR assessment can aid in identifying healthy pregnant women at risk for adverse fetal growth.