Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Pregnancy In China: A Retrospective Cohort Study

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the cause of the ongoing worldwide epidemic of Coronavirus Disease 2019 (COVID-19) in China and worldwide. However, there were few studies about the effects of SARS-CoV-2 infection on pregnant women. MethodsIn this retrospective cohort study, we enrolled 31 pregnant women and 35 non-pregnant women from Jan 28 to Feb 28, 2020 to evaluate the effects of SARS-CoV-2 infection during pregnancy. Inflammatory indices were used to assess the severity of COVID-19. Evidence of vertical transmission was determined by laboratory confirmation of SARS-CoV-2 in amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples. FindingsCompared with non-pregnant women, pregnant women had a significantly lower proportion of fever (54{middle dot}8% vs. 87{middle dot}5%, p= 0.006), a shorter average interval from onset to hospitalization (7{middle dot}80 {+/-}7{middle dot}0d vs. 13{middle dot}2 {+/-} 8{middle dot}2d, p= 0.005), and a higher proportion of severe or critical COVID-19 (32{middle dot}3% vs. 11{middle dot}4%, p=0.039). Neutrophil-to-lymphocyte ratio (NLR) and systematic immune-inflammation-based prognostic index (SII) were significantly higher on admission in severe/critical pneumonia group than moderate pneumonia group. We could not detect the presence of SARS-CoV-2 by RT-PCR in amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples. InterpretationThe clinical symptoms of COVID-19 in pregnant women were insidious and atypical, compared with those in non-pregnant patients. SII and NLR could be a useful marker to evaluate the severity of COVID-19. There was no evidence of vertical transmission during pregnancy with SARS-CoV-2 infection. FundingNational Natural Science Foundation of China and Research Funds for the Central Universities. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSWe searched PubMed, Embase and Web of science for articles published up to March 1st, 2020, using the keywords ("novel coronavirus" OR "2019 novel coronavirus" OR "2019-nCoV" OR COVID-19 OR SARS-CoV-2) AND (pregnancy OR "maternal infection" OR "fetal infection") AND "Cohort studies". We identified no published cohort studies on pregnant women with the 2019 novel coronavirus disease (COVID-19) infection. Added value of this studyFor this retrospective cohort study, we reviewed clinical records, laboratory findings, and chest CT scans from 31 pregnant women and 35 non-pregnant women from Jan 28 to Feb 28, 2020 to evaluate the effects of SARS-CoV-2 infection during pregnancy. Inflammatory indices were used to assess the severity of COVID-19. Evidence of vertical transmission was determined by laboratory confirmation of SARS-CoV-2 in amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples. Compared with non-pregnant women, pregnant women had a significantly lower proportion of fever (54{middle dot}8% vs. 87{middle dot}5%, p= 0.006), a shorter average interval from onset to hospitalization (7{middle dot}80 {+/-}7{middle dot}0d vs. 13{middle dot}2 {+/-} 8{middle dot}2d, p= 0.005), and a higher proportion of severe or critical COVID-19 (32{middle dot}3% vs. 11{middle dot}4%, p=0.039). Neutrophil-to-lymphocyte ratio (NLR) and systematic immune-inflammation-based prognostic index (SII) were significantly higher on admission in severe/critical pneumonia group than moderate pneumonia group. Amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples were tested for SARS-CoV-2 by RT-PCR and all results were negative. Implications of all the available evidenceThe clinical symptoms of COVID-19 in pregnant women were insidious and atypical, compared with those in non-pregnant patients. SII and NLR could be a useful marker to evaluate the severity of COVID-19. There was no evidence of vertical transmission during pregnancy with SARS-CoV-2 infection.