Second-Trimester Kidney Function Tied to Adverse Pregnancy Outcomes: Study

The researchers note that kidney function is not routinely assessed during pregnancy. However, several studies have suggested that renal function, particularly during the second trimester, may serve as a potential predictor of adverse pregnancy outcomes. Patients with systemic lupus erythematosus are already known to be at a higher risk for complications during pregnancy, but the specific relationship between second-trimester kidney function and adverse pregnancy outcomes remains unclear, especially in diverse populations with high obstetrical risk.

Against the above background, Anika Lucas, Department of Medicine, Duke University School of Medicine, Durham, NC, USA, and colleagues aimed to evaluate this association, providing valuable insights into the role of renal function in predicting and managing pregnancy-related complications.

In the observational study of pregnant patients with lupus across North America and Europe from 1995 to 2017, researchers utilized second-trimester creatinine levels and estimated glomerular filtration rate to assess their association with preeclampsia, preterm birth, low birth weight, fetal loss, and a composite of these outcomes. These measures were analyzed using regression models with fractional polynomials, and discrete formulations of eGFR were examined to refine the assessment.

The following were the key findings of the study:

• The study included 684 pregnancies in patients with lupus.
• The mean second-trimester creatinine level was 0.63 mg/dL, with a median of 0.60 mg/dL.
• At least one in three patients experienced an adverse pregnancy outcome.
• Both U-shaped and linear relationships were observed between kidney function and the log odds of adverse pregnancy outcomes.
• Stratification based on lupus nephritis status (active, in remission, or absent) revealed differences in the association between kidney function and adverse outcomes.

In conclusion, the investigators observed high rates of adverse pregnancy outcomes among pregnant patients with lupus, regardless of lupus nephritis status. They identified complex relationships between second-trimester kidney function and adverse pregnancy outcomes, which varied based on the specific outcome and the presence or absence of lupus nephritis.

Emphasizing the need for further research, they highlighted the importance of larger cohort studies to assess the link between second-trimester kidney function and outcomes like small-for-gestational-age births and preterm delivery, distinguishing between spontaneous and iatrogenic cases. Additionally, they suggested that tracking eGFR changes from pre-pregnancy through the second trimester could offer deeper insights into obstetrical risk.

Reference:

Lucas, Anika M.1,2,a; Miller, Cameron1; Eudy, Amanda1; Myers, Rachel1; Wyatt, Christina M.1,3; Wheeler, Sarahn4; Petri, Michelle5; Fischer-Betz, Rebecca6; Mokbel, Abir7; Nalli, Cecilia8; Andreoli, Laura8; Tincani, Angela8; Molad, Yair9; Balevic, Stephen3; Gladman, Dafna D.10; Urowitz, Murray10; Clowse, Megan E.B.1. Second (2nd) Trimester Kidney Function and Adverse Pregnancy Outcomes among Patients with Lupus. Kidney360 ():10.34067/KID.0000000738, February 14, 2025. | DOI: 10.34067/KID.0000000738