Assessment of preeclampsia risk by use of serum ionized magnesium-based equation

Abstract

Background: Preeclampsia is a common medical complication in pregnancy. It has been reported to be associated with decreased serum magnesium levels. However, there has not been evidence demonstrating utilization of change in magnesium for prediction of preeclampsia. The purpose of this study was to develop magnesium fraction-based equations which took other significant clinical risk factors into consideration for prediction of preeclampsia.

Methods: We collected serum total and ionized magnesium ionized magnesium levels from 84 pregnant women diagnosed with preeclampsia after week 20 of pregnancy. The ionized magnesium fraction was then calculated by the percentage ratio of ionized and total magnesium level.

Results: Sixty-four (76.19%) women had normal pregnancy and 20 (23.81%) developed preeclampsia. The ionized magnesium fraction was significantly lower in preeclampsia group (23.95 ± 4.7% vs. 26.28 ± 2.3%, p = .04). Additionally, lower ionized magnesium fraction (24.67%), teenage and elderly primigravida were significantly associated with preeclampsia (OR = 4.41, 95% CI: 1.46–13.40, OR = 5.47, 95% CI: 1.85–35.42 and OR = 11.11, 95% CI: 1.09–113.78, respectively). Consequently, we attempted to develop ionized magnesium fraction-based equations calculate risk scores for preeclampsia. The area of ROC for predictive accuracy of the model was 0.77 (p < .001) and ROC suggested that the score of 0.27 would be a threshold for screening preeclampsia with 70% sensitivity and 81% specificity.

Conclusions: Ionized magnesium fraction may have been appropriate for screening of preeclampsia. We suggested blood testing on total and ionized magnesium concentrations as well as calculation of ionized magnesium fraction in addition to routine antenatal care for better screening of the disease.

Keywords:

• Ionized magnesium
• preeclampsia
• hypertension
• pregnancy
• renal function

Acknowledgements

We would like to express our appreciation to the grant supported by HRH Princess Maha Chakri Sirindhorn Medical Center (MSMC), Thailand. We also would like to express our cordial thanks to the staff of the Department of Pathology, the Antenatal Care Unit, and the Labor Unit of the Department of Obstetrics and Gynecology, Faculty of Medicine, Srinakharinwirot University for clinical data review. Dr. Suthee Rattanamongkolgul (Faculty of Medicine, Srinakharinwirot University), Dr. Watcharapong Anakkamatee (Faculty of Science, Naresuan University) and Mr. Sadiporn Phuthomdee (Faculty of Science and Engineering, Kasetsart University) for mathematical and statistical consultation, as well as Dr. Julian Tam (Faculty of Medicine, University of Saskatchewan, Canada) and Miss Pairin Supsongserm (Clinical Pharmacy Department, Bangkok Hospital) for critical reading of the manuscript.

Disclosure statement

The authors have no competing financial interests.

Additional information

Funding

The authors gratefully acknowledge use of the services and facilities of HRH Princess Maha Chakri Sirindhorn Medical Center (MSMC), funded by MSMC Grant contact number 461/2557.