Research Article

A Comparative Study of Serum Sodium and Potassium Levels across the Three Trimesters of Pregnancy

Otoikhila OC and Seriki SA*

Published: 10 August, 2023 | Volume 6 - Issue 3 | Pages: 108-116

Aim: To evaluate the serum sodium and potassium levels in the three trimesters of pregnancy in women. 
Methods: Four groups of healthy women between the ages of 20 and 30 years, volunteered for this study. Group 1: Non-pregnant women (control), Group 2: Pregnant women in their first trimester, Group 3: Pregnant women in their second trimester, Group 4: Pregnant women in their third trimester. Blood samples were collected by standard aseptic method and serum samples were analyzed for serum levels of sodium and potassium by the ion selective electrode method. Results were presented as MEAN ± SEM in tables and figures, p < 0.05 was regarded as statistically significant. 
Results: The serum sodium concentrations in mmol/L were 135.3 ± 3.09, 136.3 ± 1.55, 
139.0 ± 0.78, 139.8 ± 0.91 for control, first-trimester, second-trimester, and third-trimester subjects respectively. The potassium concentrations in mmol/L were 3.678 ± 0.26, 3.687 ± 0.13,
3.820 ± 0.11, 3.767 ± 0.07 for control, first-trimester, second trimester and third-trimester subjects respectively. The Bodyweight values in kg were 72.13 ± 2.11, 74.73 ± 2.05, 75.00 ± 1.72, 
81.56 ± 4.24 for control, first-trimest, second-trimester, and third-trimester subjects respectively. 
Conclusion: Results indicate that the hormones of pregnancy altered the body weight of pregnant women, but did not change the serum sodium and potassium level across the three trimesters of pregnancy in women. This is an indication that the kidneys of healthy pregnant women can handle serum electrolyte load during the period of pregnancy.

Read Full Article HTML DOI: 10.29328/journal.cjog.1001137 Cite this Article Read Full Article PDF


Serum potassium; Serum sodium; Pregnancy hormones; Blood pressure; Trimesters


  1. Obrowski S, Obrowski M, Starski K. Normal Pregnancy: A Clinical. Acad. J. Ped. Neonatal. 2016; 1(1):15–18.
  2. Tijjani M, Abubakar E, Ibrahim AH, AIiyu SL. Effects of Pregnancy on Serum Sodium Ion and Serum Potassium Ion Concentration, Case Study of Federal Medical Centre, Nguru, Yobe State. J. of Res. in Biosci. 2014; 10:2.
  3. Opoku-Okrah C, Acquah BK, Dogbe EE. Changes in potassium and sodium concentrations in stored blood. Pan Afr Med J. 2015 Mar 12;20:236. doi: 10.11604/pamj.2015.20.236.5851. PMID: 27386032; PMCID: PMC4919675.
  4. Obembe AO, Antai AB, Ibu JO. Renal function in pregnant and non-pregnant women in Calabar – Nigeria. Niger. J. Health Biomed. Sci. 2003; 2(2):73–77.
  5. Omorogiuwa A, Ozor A. Electrolytes concentration patterns in the three trimesters of pregnancy. Int. J. Biol. Chem. Sci. 2015; 9(5): 2643-2647.
  6. Obembe AO, Antai AB. Effect of multiparity on electrolyte composition and blood pressure. Niger J Physiol Sci. 2008 Jun-Dec;23(1-2):19-22. doi: 10.4314/njps.v23i1-2.54912. PMID: 19434208.
  7. Shehan CL. The Wiley Blackwell Encyclopedia of Family Studies. John Wiley & Sons. 2016; 4: 406. 
  8. Fleischman AR, Oinuma M, Clark SL. Rethinking the definition of "term pregnancy". Obstet Gynecol. 2010 Jul;116(1):136-139. doi: 10.1097/AOG.0b013e3181e24f28. PMID: 20567179.
  9. Charles M, Gair J. Pregnancy: Condition Information. Eunice Kennedy Shriver National Institute of Child Health and Human Development. Human Pregnancy and Birth. 2013.
  10. Cheung KL, Lafayette RA. Renal physiology of pregnancy. Adv Chronic Kidney Dis. 2013 May;20(3):209-14. doi: 10.1053/j.ackd.2013.01.012. PMID: 23928384; PMCID: PMC4089195.
  11. Vinturache A, Khalil A. The Continuous Textbook of Women’s Medicine Series– Obstetrics Module, Fetal Development and Maternal Adaptation. Libr. Women's Med. 2021; 4:1756-2228.
  12. Erman A, Neri A, Sharoni R, Rabinov M, Kaplan B, Rosenfeld JB, Boner G. Enhanced urinary albumin excretion after 35 weeks of gestation and during labour in normal pregnancy. Scand J Clin Lab Invest. 1992 Sep;52(5):409-13. doi: 10.3109/00365519209088376. PMID: 1514019.
  13. Terry J. The major electrolytes: sodium, potassium, and chloride. J Intraven Nurs. 1994 Sep-Oct;17(5):240-7. PMID: 7965369.
  14. Alfarouk KO, Ahmed SBM, Ahmed A, Elliott RL, Ibrahim ME, Ali HS, Wales CC, Nourwali I, Aljarbou AN, Bashir AHH, Alhoufie STS, Alqahtani SS, Cardone RA, Fais S, Harguindey S, Reshkin SJ. The Interplay of Dysregulated pH and Electrolyte Imbalance in Cancer. Cancers (Basel). 2020 Apr 7;12(4):898. doi: 10.3390/cancers12040898. PMID: 32272658; PMCID: PMC7226178.
  15. Mohammed MI, Inuwa Y. Serum Sodium and Potassium Levels In Pregnant Women From Minjibir Local Government, Kano – Nigeria. J. of Pure and Applied Sci. 2010; 3(2):165–169.
  16. West H. Electrolytes: Definition, Functions, Imbalance, and Sources. Nutrition.
  17. Kamil F, Mirosława P, Dorota T, Roman T, Anna G, Sebastian P. Serum Potassium, Sodium and Calcium Levels in Healthy Individuals — Literature Review and Data Analysis. 2014; 53(1): 53–70.
  18. Sun Y, Mills D, Ing TS, Shapiro JI, Tzamaloukas AH. Body sodium, potassium and water in peritoneal dialysis-associated hyponatremia. Perit Dial Int. 2014 May;34(3):253-9. doi: 10.3747/pdi.2012.00201. PMID: 24863873; PMCID: PMC4033325.
  19. Metheny NM. Fluid and electrolyte balance: Nursing considerations. Jones & Sudbury, MA: Bartlett Learning. 5th 2012; 3.
  20. McCann JAS. Understanding Diseases: Nursing The Series For Clinical Excellence. Hager and Mills. 2008; 592-5.
  21. Chun TY, Bankir L, Eckert GJ, Bichet DG, Saha C, Zaidi SA, Wagner MA, Pratt JH. Ethnic differences in renal responses to furosemide. Hypertension. 2008 Aug;52(2):241-8. doi: 10.1161/HYPERTENSIONAHA.108.109801. Epub 2008 Jul 7. PMID: 18606909.
  22. Bonfils PK, Damgaard M, Taskiran M, Goetze JP, Norsk P, Gadsbøll N. Impact of diuretic treatment and sodium intake on plasma volume in patients with compensated systolic heart failure. Eur J Heart Fail. 2010 Sep;12(9):995-1001. doi: 10.1093/eurjhf/hfq100. Epub 2010 Jul 8. PMID: 20615919.
  23. Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009 Dec;114(6):1326-1331. doi: 10.1097/AOG.0b013e3181c2bde8. Erratum in: Obstet Gynecol. 2010 Feb;115(2 Pt 1):387. PMID: 19935037.
  24. Kugler JP, Hustead T. Hyponatremia and hypernatremia in the elderly. Am Fam Physician. 2000 Jun 15;61(12):3623-30. PMID: 10892634.
  25. Felver L. Fluid and electrolyte homeostasis and imbalances. Pathophysiology. 6th St. Louis: Elsevier. 2018; 521–40.
  26. Vander A, Sherman J, Luciano D. Human physiology — The Mechanisms of Body Function. 8th ed. McGraw-Hill, Boston. 2001.
  27. Morth JP, Pedersen BP, Toustrup-Jensen MS, Sørensen TL, Petersen J, Andersen JP, Vilsen B, Nissen P. Crystal structure of the sodium-potassium pump. Nature. 2007 Dec 13;450(7172):1043-9. doi: 10.1038/nature06419. PMID: 18075585.
  28. Sadava D, Heller HC, Orians GH, Purves WK, Hillis DM. Life: The Science of Biology. Gordonsville: Sinauer Associates. 2008; 10-124.
  29. Aronson PS, Giebisch G. Effects of pH on potassium: new explanations for old observations. J Am Soc Nephrol. 2011 Nov;22(11):1981-9. doi: 10.1681/ASN.2011040414. Epub 2011 Oct 6. PMID: 21980112; PMCID: PMC3231780.
  30. Udensi UK, Tchounwou PB. Potassium Homeostasis, Oxidative Stress, and Human Disease. Int J Clin Exp Physiol. 2017;4(3):111-122. doi: 10.4103/ijcep.ijcep_43_17. PMID: 29218312; PMCID: PMC5716641.
  31. Terker AS, Zhang C, McCormick JA, Lazelle RA, Zhang C, Meermeier NP, Siler DA, Park HJ, Fu Y, Cohen DM, Weinstein AM, Wang WH, Yang CL, Ellison DH. Potassium modulates electrolyte balance and blood pressure through effects on distal cell voltage and chloride. Cell Metab. 2015 Jan 6;21(1):39-50. doi: 10.1016/j.cmet.2014.12.006. PMID: 25565204; PMCID: PMC4332769.
  32. Moriguchi T, Urushiyama S, Hisamoto N, Iemura S, Uchida S, Natsume T, Matsumoto K, Shibuya H. WNK1 regulates phosphorylation of cation-chloride-coupled cotransporters via the STE20-related kinases, SPAK and OSR1. J Biol Chem. 2005 Dec 30;280(52):42685-93. doi: 10.1074/jbc.M510042200. Epub 2005 Oct 31. PMID: 16263722.
  33. Youn JH. Gut sensing of potassium intake and its role in potassium homeostasis. Semin Nephrol. 2013 May;33(3):248-56. doi: 10.1016/j.semnephrol.2013.04.005. PMID: 23953802; PMCID: PMC3748407.
  34. Foley K, Boguslavsky S, Klip A. Endocytosis, recycling, and regulated exocytosis of glucose transporter 4. Biochemistry. 2011 Apr 19;50(15):3048-61. doi: 10.1021/bi2000356. Epub 2011 Mar 25. PMID: 21405107.
  35. Reyes N, Gadsby DC. Ion permeation through the Na+,K+-ATPase. Nature. 2006 Sep 28;443(7110):470-4. doi: 10.1038/nature05129. PMID: 17006516.
  36. Baltazar RF. Hypokalaemia. In: McMillan L, editor. Basic and Bedside Electrocardiography: Lippincott Williams & Wilkins. 2009; 407.
  37. Pallavi PC, Pranay AJ, Jasmin HJ. Changes in serum calcium and Magnesium level in preeclampsia vs normal pregnancy. International J. of Biomedical and Advance Research. 2012; 3(6): 511-513.
  38. Indumati V, Kodliwadmath MV, Sheela MK. The Role of Serum Electrolytes in Pregnancy Induced Hypertension. J. of Clin. and Diagnostic Res. 2011; 5(1):66-69.
  39. Faisal AR, Ali R, Maha MB, Tariq HK. Sodium imbalance in preeclampsia. Iraqi. J. Med. Sci. 2009; 1:41-48.
  40. Sullivan CA, Martin JN Jr. Sodium and pregnancy. Clin Obstet Gynecol. 1994 Sep;37(3):558-73. doi: 10.1097/00003081-199409000-00009. PMID: 7955644.
  41. Liamis G, Liberopoulos E, Barkas F, Elisaf M. Spurious electrolyte disorders: a diagnostic challenge for clinicians. Am J Nephrol. 2013;38(1):50-7. doi: 10.1159/000351804. Epub 2013 Jun 26. PMID: 23817179.
  42. Diorgu F, Friday CN. The concentration of sodium, potassium, chloride, and calcium across the trimester of pregnancy. M. O. J Women’s Health. 2021; 10(1):1‒3.
  43. Motosko CC, Bieber AK, Pomeranz MK, Stein JA, Martires KJ. Physiologic changes of pregnancy: A review of the literature. Int J Womens Dermatol. 2017 Oct 21;3(4):219-224. doi: 10.1016/j.ijwd.2017.09.003. PMID: 29234716; PMCID: PMC5715231.
  44. Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines. Weight Gain during Pregnancy: Reexamining the Guidelines. Rasmussen KM, Yaktine AL, editors. Washington (DC): National Academies Press (US); 2009. PMID: 20669500.
  45. Catalano PM, Shankar K. Obesity and pregnancy: mechanisms of short term and long term adverse consequences for mother and child. BMJ. 2017 Feb 8;356:j1. doi: 10.1136/bmj.j1. PMID: 28179267; PMCID: PMC6888512.
  46. Frank H, Geoffrey C. Clinical Physiology in Obstetrics Subsequent Edition Reproductive Medicine & Technology. 1991; 486:296.
  47. Parrettini S, Caroli A, Torlone E. Nutrition and Metabolic Adaptations in Physiological and Complicated Pregnancy: Focus on Obesity and Gestational Diabetes. Front Endocrinol (Lausanne). 2020 Nov 30;11:611929. doi: 10.3389/fendo.2020.611929. PMID: 33424775; PMCID: PMC7793966.
  48. Lumbers ER, Pringle KG. Roles of the circulating renin-angiotensin-aldosterone system in human pregnancy. Am J Physiol Regul Integr Comp Physiol. 2014 Jan 15;306(2):R91-101. doi: 10.1152/ajpregu.00034.2013. Epub 2013 Oct 2. PMID: 24089380.
  49. Stephansson O, Dickman PW, Johansson A, Cnattingius S. Maternal hemoglobin concentration during pregnancy and risk of stillbirth. JAMA. 2000 Nov 22-29;284(20):2611-7. doi: 10.1001/jama.284.20.2611. PMID: 11086368.
  50. Stephanie B, Andrei B. Hypertension in pregnancy: Pathophysiology and treatment. https://orcid.org/0000-0003-1339 3934 abratean@ccf.orgView all authors and affiliations https://doi.org/10.1177/205031211984 April 10, 2019


Figure 1

Figure 1

Figure 1

Figure 2

Figure 1

Figure 3

Figure 1

Figure 4

Figure 1

Figure 5

Similar Articles

Recently Viewed

  • Anemia due to a rare anomaly - Case Report
    S Nanthakumar*, Sumathi Bavanandam, Nirmala Dheivamani, Natarajan B and Krishna Mohan S Nanthakumar*,Sumathi Bavanandam,Nirmala Dheivamani,Natarajan B, Krishna Mohan. Anemia due to a rare anomaly - Case Report . Ann Clin Gastroenterol Hepatol. 2017: doi: 10.29328/journal.hcg.1001002; 1: 004-006
  • Intraepidermal Injections of Autologous Epidermal Cell Suspension: A new promising approach to Dermatological Disorders. Preliminary Study
    Fabio Rinaldi*, Elisa Borsani, Luigi Fabrizio Rodella, Elisabetta Sorbellini, Rita Rezzani, Daniela Pinto, Barbara Marzani, Giovanna Tabellini and Mariangela Rucco Fabio Rinaldi*,Elisa Borsani,Luigi Fabrizio Rodella,Elisabetta Sorbellini,Rita Rezzani,Daniela Pinto,Barbara Marzani,Giovanna Tabellini,Mariangela Rucco. Intraepidermal Injections of Autologous Epidermal Cell Suspension: A new promising approach to Dermatological Disorders. Preliminary Study. J Stem Cell Ther Transplant. 2017: doi: 10.29328/journal.jsctt.1001007; 1: 066-070
  • Beta-1 Receptor (β1) in the Heart Specific Indicate to Stereoselectivity
    Rezk Rezk Ayyad*, Ahmed Mohamed Mansour, Ahmed Mohamed Nejm, Yasser Abdel Allem Hassan, Norhan Hassan Gabr and Ahmed Rezk Ayyad Rezk Rezk Ayyad*, Ahmed Mohamed Mansour, Ahmed Mohamed Nejm, Yasser Abdel Allem Hassan, Norhan Hassan Gabr, Ahmed Rezk Ayyad. Beta-1 Receptor (β1) in the Heart Specific Indicate to Stereoselectivity. Arch Pharm Pharma Sci. 2024: doi: 10.29328/journal.apps.1001060; 8: 082-088
  • Screening of antibiotic residue in poultry in Kathmandu valley of Nepal: A cross-sectional study
    Rajiv Sapkota*, Ramila Raut, Sujan Khanal, Muna Gyawali and Dipesh Sahi Rajiv Sapkota*,Ramila Raut,Sujan Khanal,Muna Gyawali,Dipesh Sahi. Screening of antibiotic residue in poultry in Kathmandu valley of Nepal: A cross-sectional study. Arch Pharm Pharma Sci. 2019: doi: 10.29328/journal.apps.1001017; 3: 079-081
  • Melaleuca Essential Oil (Melaleuca alternifolia cheel) in the Control of Beans Diseases
    Matthieu Octaveus*, Gilmar Franzener and Lisandro Tomas da Silva Bonome Matthieu Octaveus*, Gilmar Franzener, Lisandro Tomas da Silva Bonome. Melaleuca Essential Oil (Melaleuca alternifolia cheel) in the Control of Beans Diseases. J Plant Sci Phytopathol. 2024: doi: 10.29328/journal.jpsp.1001140; 8: 100-109

Read More

Most Viewed

Read More

Help ?