Serum sodium and potassium levels in mothers with term and preterm delivery: a case-control study

Introduction: Preterm labor is a common concern of the World Health Organization. Studies have shown that Potassium and sodium channels in the smooth muscles of the uterus are involved in causing uterine contractions. Therefore, this study was performed with aim to evaluate the serum levels of sodium and potassium in preterm labor. Methods: This case-control study was performed on 86 pregnant women referred to Gonabad Allameh Behlool Hospital in 2019-2020 in two groups of preterm and term delivery. The two groups were matched in terms of body mass index in early pregnancy, number of pregnancies and deliveries, level of education, income, and employment status. Blood sample was taken from the mothers after obtaining the inclusion criteria at the time of admission in labor to assess serum sodium and potassium levels. Demographic and midwifery information were collected using a questionnaire and patient's file. Data were analyzed by SPSS statistical software (version 26), and Mann-Whitney, Chi-square and Fisher tests. P< 0.05 was considered statistically significant. Results: The mean serum sodium level in the case group (123.98±21.11 mEq/L) was lower than the control group (131.43±11.39 mEq/L) and the mean serum potassium level in the case group (4.66±5.92 mEq/L) was more than the control group (3.82±0.34 mEq/L) but these differences were not statistically significant (p> 0.05). Conclusion: There is no relationship between serum sodium and potassium levels with preterm delivery. To investigate the relationship between maternal serum sodium and potassium and preterm delivery, further research is needed to evaluate the intracellular level of sodium and potassium.