Association between pregnancy-related changes in serum creatinine and preeclampsia diagnosis

Preeclampsia is a leading cause of maternal and neonatal morbidity and mortality, affecting 2-8% of all pregnancies. Typically, the increased glomerular filtration rate of pregnancy results in a decrease in serum creatinine. It is unknown if women without the expected decrease in serum creatinine during pregnancy are more likely to be diagnosed with preeclampsia.

We sought to determine if the absence of a pregnancy-related decrease in serum creatinine was associated with the development of preeclampsia in patients deemed to be at high risk for developing preeclampsia. We hypothesized that the absence of the expected decrease in serum creatinine may be a marker of impaired renal function and therefore may be associated with increased risk of preeclampsia in this cohort.

We conducted a retrospective cohort study of deliveries between November 2, 2017 and June 30, 2020 at a single institution. Pregnancies were included if a baseline serum creatinine (measured between one year prior to conception through 6 weeks gestation), and another serum creatinine value prior to 20 weeks of gestation were measured. Decrease in serum creatinine was defined as any decrease (at least 0.01 mg/dL) from baseline. The primary outcome was diagnosis of preeclampsia. Exclusion criteria included fetal anomalies, fetal demise, multiple gestation, or delivery prior to 20 weeks. Bivariable analyses were performed using Chi-square, ANOVA, and Student's t test. Logistic regression was used to determine odds of developing preeclampsia controlling for confounders.

We identified 392 pregnancies that met inclusion criteria. Preeclampsia was diagnosed in 56 (14.3%) pregnancies. Patients diagnosed with preeclampsia were more likely to have a history of preeclampsia in a prior pregnancy, chronic hypertension (HTN), and diabetes. They were also more likely to have aspirin prescribed in the current pregnancy. Prevalence of advanced maternal age, multiparity, obesity, smoking, history of autoimmune disease, history of CKD, gestational HTN, or multiple pregnancy were not significantly different between patients with and without a diagnosis of preeclampsia. After controlling for confounders, a decrease in serum creatinine from baseline was not significantly associated with a diagnosis of preeclampsia (OR 0.76, CI 0.32-1.78).

After controlling for risk factors associated with preeclampsia, a decrease in serum creatinine from baseline was not significantly associated with a diagnosis of preeclampsia in this high-risk cohort.