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The novel coronavirus, also known as SARS-CoV-2, is the virus that causes the illness we now know as COVID-19. This coronavirus is described as novel because it is a new mutation of a virus with which we have already grown familiar. Called coronavirus because of the spiky proteins that poke out from its outer envelope like a crown, the coronavirus family has been with the human race for quite a while. In fact, some coronaviruses are responsible for the common cold. Recently, however, we’ve seen some other, more deadly, mutations in the form of MERS (Middle East Respiratory Syndrome) and SARS (Severe Acute Respiratory Syndrome). Even more recently, we’ve seen the widespread emergence of SARS-CoV-2 which has led to many people around the globe suffering the effects of COVID-19.
What We Know
Because COVID-19 is so new, we have very little data about how this disease affects pregnant women. At this point, however, we can make some conclusions based on four things: 1) what we know about how a mother’s immune system changes during pregnancy, 2) how other viral infections like influenza (the flu) affect pregnant women, 3) how other coronaviruses (MERS and SARS) affect pregnant women, and 4) data based on the cases of a small sample of pregnant women affected by COVID-19 in the recent outbreak in China.
First, we already know that a woman’s immune system changes to accommodate a pregnancy. Specifically, her body must suppress an immune response to antigens from the father. Antigens are foreign substances that usually elicit an immune response. If the father’s antigens cause an immune response in the mother, then the mother’s immune system would see the fetus as a foreign invader and recruit immune cells to fight it. We do not want this to happen. This means that, during a healthy pregnancy, a woman’s response to infections may be different than what we would normally expect to see in a non-pregnant woman.
Let’s continue with what we know about how viral infections affect pregnant women. Viral infections often cause fevers. It is known that mothers who have fevers while pregnant, especially during the first trimester, have an increased risk of giving birth to a baby with a neural tube defect, such as spina bifida. Furthermore, we know that certain influenza infections during pregnancy increase the risk of premature delivery or having a low-birth-weight baby.
Another virus that has garnered notoriety for its adverse effects on the developing fetus is Zika virus. This virus crosses the placenta and causes underdevelopment of the fetal brain. Evidence seems to suggests that SARS-CoV-2 (the virus that causes COVID-19) does not cross the placenta. However, there are recent reports that indicate this may not be the case, so we just don’t know for sure.
Next, since SARS-CoV-2 is a relative of the coronavirus that caused the SARS outbreak a few years ago, it is helpful to look at what we know about the effects of that particular viral strain on pregnant women. When we compare pregnant women to non-pregnant women of the same age, data has shown that pregnant women had an increased risk of becoming ill, an increased risk of requiring some sort of breathing intervention, and an increased risk of death. In other words, the original SARS coronavirus posed an increased risk to pregnant women as compared to non-pregnant women.
Finally, we can look at the data from China about the effects of SARS-CoV-2 on pregnant women. Unfortunately, we do not currently have a data set comparing pregnant women to non-pregnant women of the same age in that circumstance, so we cannot make a direct comparison (the International Registry of Coronavirus Exposure in Pregnancy intends to fill this data gap). However, the data show that pregnant women aren’t any more vulnerable to COVID-19 than the general population. Keep in mind, though, that the general population includes people of all ages.
What We Don’t Know
There are still many questions surrounding how COVID-19 affects pregnant women and babies. For example, there is something called vertical transmission, whereby a baby can contract a disease from the mother in the period of time preceding, during, or immediately after being born. Some diseases, like the herpes simplex virus, can be passed from mother to baby while the baby is travelling through the birth canal. For this reason, cesarean delivery (C-section) may be recommended.
Data from China show there is little evidence showing vertical transmission of coronavirus from mother to baby. However, many of the births studied in China during this time were C-sections, so we cannot say with any degree of certainty that the virus cannot be passed from mother to baby as the baby passes through the birth canal.
Another question concerns the safety of breastfeeding. Can the virus be transmitted through breastmilk? At this time, we don’t know.
Finally, we can ask a question about antibodies: If a mother gets the coronavirus and recovers, are her antibodies then transferred to baby? Some recent evidence suggests this may be the case, but, again, we do not have a large enough sample size to determine this with any degree of certainty.
What is clear is that the best way to protect yourself and your baby is to avoid getting COVID-19 in the first place. Make sure you and those in your household are practicing good hand hygiene. Similarly, if you and/or those close to you must leave the house, make sure to practice proper social distancing by maintaining a distance of 6 feet or more away from others.