Maternal and Fetal Prognosis in Pregnant Women with Renal Disease Associating Urinary Tract Infection

Pregnancy related acute renal injury is a challenging diagnosis, mainly due to, among other factors, the physiological decrease in blood nitrogen retention parameters. As a consequence, the criteria required to establish the diagnosis may be first met as a result of the complications that appear, especially hypertension. The maternal and fetal complications which may occur in pregnancies with renal failure can be worsened by the relative immunodeficiency during pregnancy, which represents an elusive mechanism that is associated with a high risk of urinary tract infection (UTI). Therefore, the risk for intensive care unit admission, or developing sepsis, or preterm birth can increase.

The present study aims to investigate whether the superimposition of UTI over an altered renal function leads to a worsened maternal and fetal prognosis.

We performed an observational retrospective study that included pregnant women with increased serum creatinine levels, both with and without UTI. Thus, we analyzed 47 pregnant women who delivered in our unit between 1 January 2021 and 1 September 2023. Patients were divided into three groups: an acute renal injury (AKI) group (n=16), a chronic kidney disease (CKD) group (n=8) and a control group (n=23) which included patients with serum creatinine levels between 0.80-1 mg/dL. We evaluated the maternal and fetal complications in all three groups, taking into consideration the comparison between maternal and fetal parameters in women with UTI.

Our study highlighted an important difference between fetal weight at delivery by patients with AKI associating UTI and the two remaining groups (1395 ± 992.50 grams compared to 2340 grams in the CKD group and 3103.33±83.86 grams in the control group, respectively). There was no statistically significant difference regarding preterm birth, intrauterine grow restriction, stillbirth or neonatal intensive care unit (NICU) admission. Preterm birth had a higher incidence in all patients with AKI (87.5% compared to 50% and 34.78%, respectively).

Neonatal complications are important in pregnant women with AKI and CKD, irrespective of the UTI diagnosis. Most fetal complications occurred in patients diagnosed with AKI. The correlations highlighted by us should be studied further.