No Evidence of Intrauterine Vertical Transmission of 2019 Coronavirus Disease

By Will Boggs MD

February 26, 2020

NEW YORK (Reuters Health) - There has been no evidence of intrauterine transmission of 2019 novel coronavirus (SARS-CoV-2) infection from mother to fetus, according to a retrospective review.

Previous reports have found little evidence of vertical transmission of other coronaviruses associated with severe acute respiratory syndrome (SARS). Whether SARS-CoV-2 disease (COVID-19) can be transferred from mother to child in utero remains uncertain.

Dr. Wei Hou of Wuhan University, Wuhan, in China, and colleagues describe the clinical characteristics and intrauterine vertical transmission potential of SARS-CoV-2 infection in their retrospective review of medical records from nine pregnant women with COVID-19 pneumonia in a report in The Lancet.

All nine women tested positive for SARS-CoV-2 by PCR on samples from the respiratory tract.

In contrast, PCR detected no SARS-CoV-2 in amniotic fluid, cord blood, neonatal throat swab, or breast milk samples collected from six patients.

Clinically, the women presented with fever (none over 39 C) and symptoms of an upper-respiratory-tract infection, but none developed severe pneumonia or died of COVID-19 pneumonia.

All nine live births had a one-minute Apgar score of 8-9 and a five-minute Apgar score of 9-10. There were no fetal deaths, neonatal deaths, or neonatal asphyxia.

"Based on our findings in these nine 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 authors conclude.

"Considering the significance of this ongoing global public health emergency, although our conclusions are limited by the small sample size, we believe that the findings reported here are important for understanding the clinical characteristics and vertical transmission potential of COVID-19 infection in pregnant women," they add.

"Because of the small number of cases analyzed and the short duration of the study period, more follow-up studies should be done to further evaluate the safety and health of pregnant women and newborn babies who develop COVID-19 infection," writes Dr. Jie Qiao of Peking University Third Hospital, in Beijing, in a linked editorial.

He adds, "The National Health Commission of China launched a new notice on Feb. 8, 2020, which proposed strengthening health counselling, screening, and follow-ups for pregnant women, reinforcing visit time and procedures in obstetric clinics and units with specialized infection control preparations and protective clothing, and emphasized that neonates of pregnant women with suspected or confirmed COVID-19 infection should be isolated in a designated unit for at least 14 days after birth and should not be breastfed, to avoid close contact with the mother while she has suspected or confirmed COVID-19 infection."

In a paper in The Lancet Child & Adolescent Health, Dr. Yuan Shi and colleagues, on behalf of the National Clinical Research Center for Child Health and Disorders and Pediatric Committee of the Medical Association of Chinese People's Liberation Army, propose a contingency plan to address COVID-19 outbreaks in neonatal intensive-care units (NICUs).

This plan recommends admission of all probable or laboratory-confirmed neonates with COVID-19 to NICUs, where they should receive general management that includes close follow-up of bloodwork and chest radiography, along with respiratory support where necessary.

Neonates who have no fever for at least three days and improved respiratory symptoms; resolution of any abnormal chest radiography findings; and two nasopharyngeal and nasal swabs negative for SARS-CoV-2 at least 48 hours apart could be discharged home.

All other neonates newly admitted to the NICU should be screened for high risk of COVID-19, and high-risk neonates who develop manifestations similar to COVID-19 should be isolated and referred to a designated hospital for such infections.

Dr. David A. Schwartz of the Medical College of Georgia, in Augusta, recently reviewed potential maternal and infant outcomes from SARS-COV-19 and just returned from the 3rd International Conference on Zika Virus and Aedes Related Infections, where there was a special seminar on the novel coronavirus.

He told Reuters Health by email, "Previous experience with such coronavirus infections as SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) indicates that they are high risk for mothers when they occur during pregnancy, having caused poor obstetric outcomes including maternal death and miscarriage. However, there has never been a case of intrauterine transmission of virus from a mother with SARS or MERS to the fetus."

"Following communications with my colleagues in the U.S. and China, as of today, February 20th, there have been no confirmed incidents of intrauterine maternal-fetal transmission of the SARS-CoV-2 virus between pregnant women with COVID-19 and their unborn infants," he said.

"Pregnant women with COVID-19 are high-risk patients and should be treated accordingly," added Dr. Schwartz, who was not involved in the new study. "SARS-CoV-2 has been shown to produce severe lower respiratory disease including acute respiratory distress syndrome (ARDS) and diffuse alveolar damage (DAD) in the lungs, which can be life threatening to both pregnant and non-pregnant patients. If newborn infants were to develop pulmonary infection as a result of SARS-CoV-2 infection, it could result in a fatal outcome."

Dr. Hou and co-author Dr. Huixia Yang did not respond to a request for comments.

SOURCE: and The Lancet, online February 12, 2020. The Lancet Child & Adolescent Health, online February 7, 2020.