Coronavirus disease 2019 during pregnancy: do not underestimate the risk of maternal adverse outcomes.

To the Editor:

Accurate data are essential to understand the potential consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy. Until recently, no relevant or reliable data regarding potential adverse maternal outcomes were available. Thanks to Breslin and colleagues, we now know more about the maternal condition after coronavirus disease 2019 (COVID-19) infection during pregnancy. In their study, the authors initially assessed pregnant women presenting with symptoms, followed by systematic testing for every woman presenting to their maternity unit. Among 43 patients, 37 (86%) had mild clinical symptoms, 4 (9%) were considered as severe cases, and 2 others (5%) were admitted to the intensive care unit. The authors stated that these rates are likely similar to the general population: 81%, 14%, and 5% with mild, severe, and critical diseases, respectively, according to Wu and McGoogan.

However, we should not compare apples and oranges. Pregnant women enrolled in the study by Breslin et al had a mean age of 29.7 years (standard deviation, 6.0). The age distribution of patients included in the study by Wu and McGoogan was significantly higher, with only 10% of patients under the age of 30 years (Figure ).

Figure

Severity of cases and age distribution in the studies by Breslin et al and Wu and McGoogan

Favre G. COVID-19 during pregnancy. AJOG MFM 2020.

Stating that pregnant women present with similar rates of adverse outcomes as a group of older patients would ignore one of the main cofactors known to contribute to severe and critical disease in SARS-CoV-2 infections. Comparing maternal complications with an older population afflicted with COVID-19 may critically underestimate the potential contribution of pregnancy as a risk factor. Moreover, the denominator in the study by Breslin et al included 6 asymptomatic patients, whereas other studies reported rates of adverse outcomes in patients diagnosed with COVID-19 after symptom onset. Therefore, the proportion of pregnant women exhibiting mild, severe, or critical COVID-19–related illness could be more significantly underestimated. Overall, pregnant women with COVID-19 infection should be treated with additional caution.