Covid and pregnancy: what we know about what happens to your immune system

New infections pose unique challenges for people who are pregnant during the outbreak. Effects of monkeys, deer and influenza pregnancy It highlights the potential immediate and long-term adverse health outcomes that the virus can bring to both mothers and babies. These risks include preterm birth of babies in Sar, birth defects due to Zika, and an increased risk of severe influenza.

Need to worry pregnancy And Covid-19? There are many things to think about. They fall into two broad areas related to their effects on the fetus and on the pregnant woman itself.

In either case, pregnancy Not only the long-term health effects of both parents and children. Early evidence we have shows that changes in the immune system during pregnancy may be somewhat protective against this disease.

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Early data from pregnant women on Covid-19 show that the disease Premature birth Change to and placenta It may reflect changes in blood flow. This suggests that virus-related confusion occurs between the parent and the fetus.

However, these studies were about women with severe cases of the disease. Little is known about the effects of mild illness or subclinical infections during pregnancy. It’s important to understand this As research It emphasizes that asymptomatic, mildly infected pregnant women are much more likely than pregnant women requiring hospitalization for Covid-19.

This shows that pregnant people are less susceptible to severe Covid-19.

The obvious protective effect of pregnancy against severe disease is simply Different immune reactions Severe Covid-19 seen in men and women, and the fact that men generally die of the disease more than women. However, the absence of the same response in pregnancy with other viruses such as influenza suggests that something else is working with SARS-CoV-2.

Fetus

So far, the fetus seems to be very well protected from SARS-CoV-2 mother-to-child transmission ( Vertical transmission) And such passages are possible but seem unusual. This may be due to the natural features of the placenta that produce molecules that stop the virus from binding to placental cells. Placental membranes may also limit infection by the virus.

Of course, it is very difficult to study the placenta before giving birth. Alternatives such as analysis of cell debris released from placenta ( Extracellular vesicleIt can be found in a sample of maternal blood, but it is really needed to find out what functions of the placenta protect the fetus from infection and how the virus affects the placenta.

Antibodies made by a mother infected with SARS-CoV-2 pass through the placenta and are transmitted to the fetus (known as passive immunity). This provides short-term protection from many infectious agents during the last months of pregnancy and the months after the baby is born. These antibodies also continue to be provided in breast milk if the baby is breast-fed.

Early research from China Antibodies that protect against Covid-19 have been shown to be present in newborns of women who had such antibodies.

this is, Passive immunity, SARS-CoV-2 occurs when the baby basically inherits the antibody from the parent. To better understand the role of these antibodies in virus neutralization and baby protection, some larger studies are needed to investigate whether anti-SARS-CoV-2 antibodies are present in breast milk. is.

Molecules other than antibodies can also transfer from the parent to the fetus. Pregnant women with severe Covid-19 have many of the features of the inflammatory response seen in other people with similar symptoms. This includes high level molecules such as: Interleukin-6 (IL-6), Which indicates that the immune response has been activated.

There are many studies showing that maternal immune activation can have deleterious effects on the developing fetus. Such activation can be associated with respiratory, cardiovascular, Nerve development And other obstacles to offspring. It remains unclear whether SARS-CoV-2 has such long-term effects on the health of these children.

Role of the immune system

so Previous article, We discussed how the immune system changes during pregnancy, which is a unique feature of this and other dynamic adaptations that occur with pregnancy that protects against severe Covid-19. May offer.

Other examples of possible defense mechanisms include different receptor molecules that SARS-CoV-2 uses to enter human cells. Angiotensin converting enzyme 2 (ACE2) Best known these Virus entry receptor However, CD147, CD26, etc. also play this role.

All of these receptors change May contribute to recovery during pregnancy. These receptors are Soluble type It can be measured in blood or breast milk and acts as a decoy receptor, blocking the virus from binding to cells.

What’s next?

A detailed explanation of why pregnant people and their children seem relatively resilient to severe Covid-19 helps to understand the process of other illnesses and identify ways to combat them. I will.

Work from British Obstetric Surveillance System As with the wider population, pregnant Asian and Black women have been shown to be more likely to be hospitalized for SARS-CoV-2 infection. Therefore, studies of Covid-19 during pregnancy should consider the effects of ethnicity and other risk factors.

This is especially important because these studies support efforts towards the use of vaccines during pregnancy.

April Wreath, A postdoctoral fellow in immunology, Swansea University And Catherine Thornton, Professor of Human Immunology, Swansea University

This article is reissued from conversation Under Creative Commons license. Read Original work..