Selenium supplementation of pregnant women at a high risk of preeclampsia has shown beneficial effects on 1) serum selenium levels, 2) some metabolic profiles, 3) uterine artery pulsatility index, and 4) mental health, compared to placebo. The study compared the effect in 60 pregnant women of supplementation with 200 mcg/day for 12 weeks with the effect of placebo for the same period.
The supplementation took place for 12 weeks starting in weeks 16 to 18 of pregnancy. No side effects related to the intake of 200 mcg of selenium per day by pregnant women at high risk of preeclampsia were reported throughout the duration of the study [Mesdaghinia 2022].
Selenium Supplementation Compared to Placebo
How did the selenium supplementation compare with the placebo supplementation in the pregnant women?
- Selenium supplementation was associated with a significant increase in serum selenium levels.
- Selenium supplementation was associated with a significant increase in total antioxidant capacity and in total glutathione levels.
Note: Total antioxidant capacity = a measure of the cumulative activity of all antioxidants in the blood; glutathione = an endogenous antioxidant.
- Selenium supplementation was associated with a significant reduction in high-sensitivity C-reactive protein levels.
Note: C-reactive proteins levels in the blood are a bio-maker for the extent of inflammation in the body.
- Selenium supplementation was associated with a significant decrease in the pulsatility index of the uterine artery in Doppler ultrasound.Note: The pulsatility index is a measure of the systolic and diastolic velocities in the uterine.
- Selenium supplementation was associated with a significant improvement in depression, anxiety, and sleep quality.
Meta-Analysis of Selenium Status and Risk of Preeclampsia
A 2016 systematic review and meta-analysis of data from 13 observational studies with 1515 participants and 3 randomized controlled trials with 439 participants has led researchers to the following conclusions [Xu 2016]:
- Evidence from observational studies shows an inverse association between blood selenium level and the risk of preeclampsia.
- Supplementation with selenium significantly reduces the incidence of preeclampsia.
Randomized Controlled Trials of Selenium Supplementation and Risk of Preeclampsia
- In 2014, Rayman et al reported the results of a pilot study in which the researchers randomly assigned 230 first-time pregnant women to a selenium treatment group (60 mcg/day) or a placebo treatment group from 12 to 14 weeks of pregnancy until delivery.
Between week 12 and week 35, whole-blood selenium concentration increased significantly in the selenium-treated group and decreased significantly in the placebo group. At 35 weeks, there were significantly higher concentrations of whole-blood selenium and plasma selenoprotein P in the selenium-treated group than in the placebo-treated group [Rayman 2014].
At week 35, the concentration of serum soluble vascular endothelial growth factor receptor-1 (sFlt-1) was significantly lower in the selenium-treated group than in the placebo-treated group in the study participants in the lowest quartile of selenium status at baseline. The status of sFlt-1 in the serum is a bio-marker associated with the risk of preeclampsia [Rayman 2014].
The study results indicate that selenium supplementation has the potential to reduce the risk of pre-eclampsia in pregnant women with low selenium status.
- In 2010, Tara et al reported the results of a pilot study in which the researchers randomly assigned 166 first-time pregnant women, who were in the first trimester of pregnancy, to receive 100 mcg of selenium or a placebo per day until delivery.
The study data showed the following outcomes [Tara 2010]:
- There were no major side effects associated with the selenium supplementation.
- There was a significant increase in mean serum selenium concentrations at term in the selenium supplemented group. The mean serum selenium concentrations in the placebo group remained unchanged.
- The incidence of preeclampsia was lower in the selenium group (n = 0) than in the placebo group (n = 3); however, this difference was not statistically significant.
- The researchers concluded that their findings indicate that selenium supplementation in pregnant women may be associated with a lower frequency of preeclampsia [Tara 2010].
Conclusion: Selenium Status and Risk of Preeclampsia
- Low selenium status is associated with increased risk of preeclampsia.
- More prospective clinical trials are needed to determine the optimal supplementation dosage, the optimal beginning time of the supplementation, and the optimal duration of the supplementation.
Mesdaghinia E, Shahin F, Ghaderi A, Shahin D, Shariat M, Banafshe H. The Effect of selenium supplementation on clinical outcomes, metabolic profiles, and pulsatility index of the uterine artery in high-risk mothers in terms of preeclampsia screening with quadruple test: a randomized, double-blind, placebo-controlled clinical trial. Biol Trace Elem Res. 2022 Feb 28. Prepub ahead of print.
Rayman MP, Searle E, Kelly L, Johnsen S, Bodman-Smith K, Bath SC, Mao J, Redman CW. Effect of selenium on markers of risk of pre-eclampsia in UK pregnant women: a randomised, controlled pilot trial. Br J Nutr. 2014 Jul 14;112(1):99-111.
Tara F, Maamouri G, Rayman MP, Ghayour-Mobarhan M, Sahebkar A, Yazarlu O, Ouladan S, Tavallaie S, Azimi-Nezhad M, Shakeri MT, Boskabadi H, Oladi M, Sangani MT, Razavi BS, Ferns G. Selenium supplementation and the incidence of preeclampsia in pregnant Iranian women: a randomized, double-blind, placebo-controlled pilot trial. Taiwan J Obstet Gynecol. 2010 Jun;49(2):181-7.
Xu M, Guo D, Gu H, Zhang L, Lv S. Selenium and preeclampsia: a systematic review and meta-analysis. Biol Trace Elem Res. 2016 Jun;171(2):283-292.
The information presented in this review article is not intended as medical advice and should not be used as such.
30 March 2022