Premature infant born to a convalescent mother with COVID-19 in mid-term pregnancy

We report a female infant born preterm to a woman at 35 gestational weeks and four days in a normal pregnancy prior to delivery, with normal liquor volume and good maternal and infant outcomes. The baby was transferred to the neonatal department 30 min after birth at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, on March 21, 2020. The infant weighed 2 800 g with 7 and 9 Apgar scores respectively at 1 and 5 min. The mother had been diagnosed with COVID-19 at 26+6 weeks of pregnancy and the maternal serum level of IgM was negative and that of IgG was 20.77 AU/ml (normal reference <10 AU/ml) before delivery. The baby had hypoglycemia on admission, and the blood sugar stabilized after treatment. Though early mild feeding intolerance occurred, the baby was able to feed normal by eight days after birth. The baby was in good condition during hospitalization and discharged. Throat swab specimens obtained from the infant on the 2nd, 3rd and 8th day after birth for SARS-Cov-2 RNA detection were all negative. On the 2nd and 8th day after birth, SARS-Cov-2 IgM in the neonatal serum were negative, while elevated IgG levels of 30.2 AU/ml and 25.3 AU/ml (normal reference value <10 AU/ml) were observed, suggesting that the infant's IgG antibody of SARS-CoV-2 may have come from the mother. According to this case report, no intrauterine vertical transmission was found in the pregnancy with SARS-CoV-2 infection in the second trimester, while further follow-up is still needed. Key words: Coronavirus infections; Pregnancy complications, infectious; Infectious disease transmission, vertical; Infant, premature; Pregnancy trimester, second