Selenium deficiency and preterm birth

An international team of researchers has just completed a huge study of the possible link between maternal DNA, selenium deficiency, and preterm labor. Earlier studies have shown that women with low blood selenium have an increased risk of preterm birth and that selenium supplementation may lower that risk. A problem in that respect is that climate changes and soil depletion may increase the risk of selenium deficiencies, especially in Europe.

The international team of scientists conducted a study of over 50,000 Danish, Norwegian, Finnish, and American mothers whose DNA was analyzed in detail. The results were then held up against the week of pregnancy in which the mothers’ first child was born. The researchers found three gene variations in women whose first child was delivered prematurely and before the 37th week of pregnancy. According to managing director, Professor Mads Melbye from Statens Serum Institut (SSI), this is the first time ever that anyone has linked genes to preterm birth.

A particular gene that codes for selenium turnover

The researchers looked specifically at two genes, WNT4 and EEFSEC, which code for different proteins and enzymes in the body.
WNT4 influences the signaling of the sex hormone, estrogen, which plays a key role during pregnancy. EEFSEC codes for an enzyme that is important for the turnover of the trace element selenium.
Selenium is already known to support several selenoproteins that are important for fetal development and birth.
According to Mads Melbye, the question is whether small variations in these two genes are disturbing the delicate balance of the developing fetus and causing preterm birth. If future studies show that this is the case, he speculates that one could develop nutritional supplements or medical drugs inspired by how these two gene variants affect pregnancy and birth.

Low selenium levels in the soil and preterm delivery

It is not the first time that selenium deficiencies are linked to preterm birth. The African country, Malawi, for instance, has the highest preterm birth rate in the world. At the same time, there is widespread selenium deficiency among the population, as the soil and the crops contain very little of this vital nutrient. Mads Melbye says that the next step is to take a closer look at this relation and to see if women from other countries who deliver prematurely also have less selenium in their blood compared with those who deliver on time. Available studies suggest that this is the case. Earlier research has also demonstrated that supplements of selenium yeast may help make the pregnancy and birth safer.

Selenium deficiencies increase the risk of a ruptured fetal membrane and other complications

10-20% of all pregnant women risk delivering prematurely because of a ruptured fetal membrane. According to a Dutch-British study of 1,000 women in their 12th week of pregnancy, those with the lowest selenium levels in their blood were twice as likely to deliver prematurely as were those with higher selenium levels. At the same time, women with the lowest selenium levels had an increased risk of pregnancy-related hypertension and preeclampsia.

Selenium yeast makes the pregnancy and birth safer

Pregnant women who supplement with 100 micrograms of selenium yeast daily from their first trimester until the time of delivery can reduce the risk of a ruptured fetal membrane by a third. This was shown in a placebo-controlled study that is published in the Journal of Obstetrics and Gynaecology. The study also showed that pregnant women who took supplements of selenium yeast had a lower rate of preeclampsia, which is the leading cause of preterm birth. Preeclampsia causes symptoms such as hypertension, oedemas, and proteinuria (excess protein in the urine) and may also lead to rare but potentially life-threatening conditions like eclampsia.

It is difficult to get enough selenium, even with a healthy diet

The richest sources of selenium are fish, shellfish, organ meat, eggs, dairy products, and Brazil nuts in particular. Even with a balanced diet, however, it appears to be difficult to get enough selenium, even if you consume large amounts of seafood. A Danish study from 2015 showed that daily consumption of 200 grams of fish and shellfish for a six-month period was not sufficient. Also, it is a problem that organ meat and fish (predatory fish in particular) contain mercury, which can cause harm to the unborn child.
According to the mentioned studies, it may be an advantage for pregnant women and those who plan to become pregnant to supplement with 100 micrograms of organic selenium yeast daily. Organic selenium yeast contains a variety of different organic selenium compounds just like you would get from eating a varied diet with many different selenium sources.

References

Lasse Foghsgaard. Mysteriet om for tidlig fødsel er kommet nærmere en opklaring. Politiken 07- 09-2017
DR1 Radioavisen 07-09-2017
Hilten T Mistry et al. Selenium in reproductive health. Journal of Obstetrics and Gynaecology. 2011

Fatemeh Tara et al. Selenium Supplementation and the Incidence of Preeclampsia in Pregnant Iranian Women: A Randomized, Double-Blind, Placebo-Controlled Pilot Trial. Taiwanese Journal of Obstetrics and Gynecology. 2010

Fatemeh Tara et al. Selenium supplementation and premature (pre-labor) rupture of membranes: a randomized double-blind placebo-controlled trial. Journal of Obstetrics and Gynaecology. 2010

Jones GD et al. Selenium deficiency risk predicted to increase under future climate change. Proceedings of the National Academy of Sciences 2017
Editorial team. Selenium deficiency promoted by climate change. ETHzüric 2017