Comparison of Maternal-Fetal Acid-Base Metabolism in Pregnant Patients with Severe Preeclampsia without and with Obesity

Abstract

Aims: To identify and compare maternal and fetal acid-base metabolism in pregnant patients with severe preeclampsia (SP) without and with obesity. Study Design: Cross-sectional, descriptive and analytical study. Place and Duration of Study: Intensive Care Unit (ICU) of the High Specialty Medical Unit, Gynecology and Obstetrics Hospital No. 3. National Medical Center "La Raza", Mexican Institute of Social Security, Mexico City, between January 1 and December 31, 2024. Methodology: This study was conducted in pregnant patients with SP in ICU: 36 patients with normal Body Mass Index ((BMI) <25 and 31 patients with obesity (BMI >30). Acid-base metabolism was compared with maternal arterial blood gas measurements upon admission to the ICU and umbilical artery measurements during cesarean section. Statistical analysis: descriptive statistics, Mann-Whitney U test, and chi-square test. A value P <.05 was considered significant. SPSS™ version 22 statistical software was used. Results: Maternal arterial blood gas: negative values for the BE ecf and BE (B) were found in both groups, but with a significant intergroup difference only for the BE ecf (BE ecf normal BMI -6.08±-5.38 vs obesity -9.41±-3.46 mmol/L, P=.01: BE (B) normal BMI -6.62±-2.68 vs obesity -8.11±-3.11, P=.68). Comparison of the other blood gas parameters (pH, PaCO2, Lactate, Bicarbonate, Standard bicarbonate) showed no significant differences. The findings were interpreted as a state of compensated metabolic acidosis in both groups, but with statistical significance of the BE ecf in favor of patients with obesity. Umbilical artery blood gas: negative values for the BE ecf and BE (B) were documented without significant intergroup differences (BE ecf normal IBM -7.37±-3.94 vs obesity -8.02±-3.76 mmol/L, P=.50; BE (B) normal BMI -6.48±-4.4 vs obesity -7.78±3.93 mmol/L, P=.21). Comparison of the other blood gas parameters (pH, PaCO2, Lactate, Bicarbonate, Standard bicarbonate) showed no significant differences. The findings were interpreted as a state of compensated metabolic acidosis in both groups, but without intergroup statistical significance. Conclusion: The findings were interpreted as a state of compensated maternal and fetal metabolic acidosis in both groups, but with statistical significance of the BE ecf in favor of mothers with obesity.