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Over the past year, our knowledge of the effects of COVID-19 on the body, including during pregnancy, and of how different conditions, including pregnancy, affect the outcome of this disease has been growing. New knowledge comes from studies of patients, of victims of COVID-19 who did not survive, and of the systematic review and combination of the results of small studies into larger studies (meta-analysis). Based on what has been done in this realm and published in the medical literature over the past several months, here are a few things that we can say at this point in time about the interaction between SARS-CoV2 (the virus that causes COVID-19) and reproductive biology.
Starting with the issue of fertility, so far, there has been no solid evidence published that infection with SARS-CoV2 reduces significantly the chances of getting pregnant. However, there is a hypothetical concern that the virus may indeed reduce fertility particularly of males, because of studies showing that the ACE-2 receptor —the protein that we have discussed a few times that acts as kind of a landing pad and doorway for the virus to infect cells— is made by more than one type of male reproductive cell. So this is an issue to keep on your radar screen. On the other hand, when it comes to vaccines against SARS-CoV2, as we discussed in detail in an article devoted to this topic, there is no evidence, nor rationale, for an idea that has been floated that the vaccines would interfere with a protein called syncytin-1, which is important both in the genesis of an embryo and in keeping the placenta attached to the uterus.
When it comes to how pregnancy affects the course and outcome of COVID-19 and how COVID-19 affects the course of pregnancy, there are a few things that are clear and many other things still uncertain. It’s not clear whether changes in the immune system on account of pregnancy make you more likely to become infected. This issue is very difficult to test, because women who are pregnant, or trying to become pregnant, may be acting more cautiously compared with women of similar age and health who are not pregnant and not trying to be pregnant. Mothers-to-be may be doing a better job with social distancing, masking, nutrition, and other things. If you do catch the virus, however, studies show that pregnant women are more likely than their non-pregnant counterparts to suffer a severe case of COVID-19, more likely to be admitted to the ICU, and more likely to be put on invasive ventilation, meaning on a mechanical ventilator with a tube down the throat. Such patients are often sedated and their breathing muscles are paralyzed so that they will not fight the ventilator.
On the other hand, if you suffer from a mild to medium case of COVID-19 that requires hospitalization, but not ICU admission, pregnancy does not make you more likely to need low flow oxygen through a nasal cannula (a tube in the nose). Even more interesting, even though pregnancy makes a woman more likely to need ICU admission and invasive ventilation, it does not appear to increase her risk of developing acute respiratory distress syndrome (ARDS, the main reason why patients with severe COVID-19 patients get put on invasive ventilation), nor does pregnancy make a woman more likely to be connected to extracorporeal membrane oxygenation (ECMO), a technology that bypasses the lungs, putting oxygen into, and removing carbon dioxide from, the patient’s blood directly. Pregnancy also does not increase the chances of failure of multiple organs, which is another of the terrible complications that can develop in patients with severe COVID-19. Interestingly, being pregnant makes women with COVID-19 less likely than non-pregnant patients to suffer fever and muscle pain, which may have to do with immune system changes in pregnancy.
The above is based on a large meta-analysis of almost 80 studies encompassing 11,000 patients and the take-home message is that pregnancy makes women with COVID-19 more likely to be admitted into the ICU and more likely to be on a ventilator. Now, what about the reverse question, namely how having COVID-19 affects your pregnancy and the baby? Here, as with the other question, there are a few parts to the answer. Based on the most reliable studies, so far, having an asymptomatic SARS-CoV2 infection, or even full-blown COVID-19, does not appear to increase the chances that you’ll have a cesarean section —although C-sections are very common in the first place, so you may need one for a different reason. Nor does having a SARS-CoV2 infection, symptomatic or not, increase the risk of preeclampsia (a pregnancy complication featuring high blood pressure and abnormalities of organs, usually the kidney), abnormalities of the placenta, abnormal heart rate in the mother, fetal distress, stillbirth, neonatal death, nor of an abnormal Apgar score at 5 minutes after birth (a test of various signs in the newborn that correlates with newborn health issues).
As for spontaneous abortion (miscarriage), although a study conducted last year in Italy found that 11 percent of women who suffered spontaneous abortion in the first trimester had a SARS-CoV2 infection, but a 9.6 percent infection rate in women whose pregnancies continued, the statistical analysis of that study revealed that the difference between those two percentages was not statistically significant. On the other hand, the message coming in from numerous studies is that COVID-19 does increase the rate of preterm birth substantially. In fact, having COVID-19 makes a woman three times more likely to give birth to a preterm infant compared with a woman who does not have COVID-19. It also increases the likelihood that the newborn will be admitted to the neonatal unit.