The outbreak of the novel coronavirus (COVID-19) has raised questions about whether the virus can be transmitted from mother to child. In the first study of pregnant women infected with the virus in Hubei Province, China, researchers report “no evidence for intrauterine infection caused by vertical transmission in late pregnancy,” according to study results published in the Lancet.
The researchers conducted a review of medical records from 9 pregnant women admitted to Zhongnan Hospital of Wuhan University, China, with COVID-19 pneumonia from January 20 to January 31, 2020. All patients tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The researchers reviewed clinical records, laboratory findings, and chest computed tomography (CT) scans for all patients. Maternal throat swab samples were collected and tested for SARS-CoV-2. All samples were processed simultaneously; positive confirmed cases of COVID-19 infection were defined as those samples with a positive test result.
Amniotic fluid samples from patients with COVID-19 pneumonia were obtained via direct syringe aspiration at the time of delivery. Cord blood and neonatal throat swap samples were collected immediately following delivery. In addition, breast milk samples from patients with COVID-19 pneumonia were collected at first lactation.
All patients were in their third trimester and underwent caesarean section. Patient age range was 26 to 40 years and the range of gestational weeks at admission was 26 to 39 weeks. None of the patients had underlying diseases such as diabetes, chronic hypertension, or cardiovascular disease.
Of the 9 patients, 7 presented with a fever without chills but none had fever >39°C. Additional symptoms of upper respiratory tract infection were observed: 4 patients had cough, 3 had myalgia, 2 reported sore throat, 2 indicated malaise, 1 displayed gastrointestinal symptoms, and 1 had shortness of breath and preeclampsia. None of the patients developed severe pneumonia or died of COVID-19. All patients had a chest CT scan; 8 patients showed typical findings.
All 9 live births were recorded; no fetal death, neonatal death, or neonatal asphyxia was observed. The presence of SARS-CoV-2 was tested in amniotic fluid, cord blood, neonatal throat swab, and breast milk samples, but none were positive for SARS-CoV-2.
“Notably, based on our findings in these  patients, there is currently no evidence to suggest that development of COVID-19 pneumonia in the third trimester of pregnancy could lead to the occurrence of severe adverse outcomes in neonates and fetal infection that might be caused by intrauterine vertical transmission,” the researchers concluded.
Chen H, Guo J, Wang C, et al. Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: a retrospective review of medical records [published online February 12, 2020]. Lancet. doi:10.1016/S0140-6736(20)30360-3