NEWBORN

Coronavirus transmitted to newborn through mother’s placenta

Coronavirus transmitted to newborn through mother’s placenta

Pregnant women infected with COVID-19 may pass on the disease-causing virus to their baby through the placenta, researchers in France suggest.

In their study, published in Nature Communications, the authors describe the case of a newborn child which presented with SARS-CoV-2 infection shortly after birth and subsequently suffered neurological conditions consistent with symptoms seen in adults with COVID-19.

Through analysis of the blood of mother and child as well as placenta and amniotic fluid, they give strong evidence for the virus to have been transmitted by the infected mother through the placenta. Scientists hope that taken together with other case reports, this could give indications for the risk and impact of COVID-19 infections during pregnancy.

‘This case study is indeed an important addition to the existing literature,’ commented Dr Ela Chakkarapani from the University of Bristol, who was not involved in the study. ‘Data to date has been suggesting in utero transmission may be occurring and this study adds data to further support that.’

In March 2020, the pregnant woman was hospitalised in Paris with symptoms of COVID-19 and tested positive for the virus. Despite immediate isolation after being born by caesarean section, the newborn boy developed neurological symptoms quickly – including distress and muscle spasms – which mirrored COVID-19-related effects in adults. With his health improving soon after, the baby and his mother recovered and were discharged from the hospital.

The authors conclude that based on their analysis of blood, amniotic fluid and placenta, transmission of the virus via the placenta was very likely in the reported case. This adds fire to the ongoing medical debate over the likelihood of an elevated risk of coronavirus infection for expectant mothers and their children, especially in the context of placenta-transmitted disease. According to the CDC, the major source of transmission to babies is contact with respiratory droplets from mothers or other caregivers immediately after birth.

‘It remains rare for babies to become infected; in 244 live-born babies of infected mothers in the UK, 95 percent had no sign of the virus, and outcomes are similar to non-infected babies,’ commented Professor Andrew Shennan from King’s College London. ‘This report adds knowledge to a possible mechanism of transfer to the baby, i.e, via the placenta while pregnant, but women can remain reassured that pregnancy is not a significant risk factor for them or their babies with COVID-19.’

Read more: https://www.nature.com/articles/s41467-020-17436-6

Length of pregnancy alters the child’s DNA

Length of pregnancy alters the child’s DNA

Researchers from Karolinska Institutet in Sweden have mapped the relationship between length of pregnancy and chemical DNA changes in more than 6,000 newborn babies. For each week’s longer pregnancy, DNA methylation changes in thousands of genes were detected in the umbilical cord blood. The study is published in Genome Medicine.

Premature birth, that is before 37 consecutive weeks’ of pregnancy, is common. Between 5 and 10% of all children in the world are born prematurely.

Most children will develop and grow normally, but premature birth is also linked to respiratory and lung disease, eye problems and neurodevelopmental disorders.

This is especially true for children who are born very or extremely prematurely. During the fetal period, epigenetic processes, i.e., chemical modification of the DNA, are important for controlling development and growth. One such epigenetic factor is DNA methylation, which in turn affects the degree of gene activation and how much of a particular protein is formed.

“Our new findings indicate that these DNA changes may influence the development of fetal organs,” says Simon Kebede Merid, first author of the study and PhD student at Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset.

The majority of observed DNA methylations at birth tended not to persist into childhood, but in 17% the levels were completely stable from birth to adolescence. The levels that you are born with in certain genes thus track with age.

“Now we need to investigate whether the DNA changes are linked to the health problems of those born prematurely,” says Professor Erik Melén, at the Department of Clinical Science and Education, Södersjukhuset.

Epigenetics is a hot research topic that links genes, the environment and health. This work was done within the international Pregnancy and Childhood Epigenetics (PACE) consortium. The work represents contributions from 26 studies.

Professor Melén’s group also contributed to the first PACE paper which showed that mother’s smoking during pregnancy changes DNA in newborns and lead two PACE studies showing effects of air pollution. Links to diseases such as asthma, allergy, obesity and even aging have also been shown.

“We hope that our new findings will contribute valuable knowledge about fetal development, and in the long term new opportunities for better care of premature babies to avoid complications and adverse health effects,” says Erik Melén.

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