COVID-19 does not affect pregnant mothers or their newborns

Breaking new ground 12. jan 2021 4 min Professor Henriette Svarre Nielsen Written by Kristian Sjøgren

Researchers from Denmark got busy as some of the first researchers globally to collect data on pregnant women with COVID-19. Their results show that neither the mothers nor their newborns were adversely affected by the disease.

Many pregnant women who have contracted COVID-19 have naturally been concerned about how it would affect the risk of complications to them and their child during pregnancy or childbirth.

Since scarcely anyone had heard of COVID-19 until early 2020, physicians could not provide pregnant mothers with any reassuring answers because this had never been investigated – until now.

In two studies, researchers and physicians in Denmark showed that COVID-19 in the first trimester does not appear to increase the risk of pregnancy loss. The researchers and physicians also showed that COVID-19 does not affect the risk of complications at other times in pregnancy or associated with childbirth.

“This is a very positive conclusion, with the caveat that women of childbearing age in Denmark are generally quite healthy and that all pregnant women in Denmark have access to the relevant healthcare services and therefore do not have a pre-existing high risk of complications in connection with COVID-19. In addition, Denmark had a very low incidence of COVID-19 in the first wave. In other parts of the world, with massive COVID-19 epidemics and very different levels of healthcare services, COVID-19 increases the risk of caesarean section. We did not find this among the women in this study,” explains Henriette Svarre Nielsen, Clinical Professor and specialist physician, Department of Obstetrics and Gynaecology, Copenhagen University Hospital Hvidovre, Denmark.

The research has been published in Obstetrics and Gynecology and Human Reproduction.

Rapidly initiated studies

When COVID-19 struck Denmark and the government and foundations rapidly awarded grants for research projects that could elucidate how COVID-19 affects both health and society, Henriette Svarre Nielsen and her colleagues rapidly applied for funding for a project to identify how COVID-19 affects pregnant women and their children.

The researchers tested for antibodies to SARS-CoV-2 in blood samples from pregnant women taken in connection with a nuchal translucency scan of their fetus at the end of the first trimester.

The researchers examined blood samples from 1,019 first-trimester women and 36 women with a first-trimester pregnancy loss before the scan. In addition, the researchers examined 1,019 women at the follow-up scan in the second trimester and 1,313 women who gave birth in April–June 2020.

The researchers also took blood samples from 1,188 of the women’s partners at birth, and 1,206 newborns were included.

COVID-19 does not increase the risk of pregnancy loss

The researchers found that 2.6% of the women giving birth and 3.5% of their partners had COVID-19 in the latter stages of pregnancy.

Of the first-trimester women, 53% with COVID-19 were asymptomatic versus 26% of the women who tested negative.

The results from the first trimester showed that having COVID-19 was not associated with the result from the fetal nuchal translucency scan or the risk of pregnancy loss in the first trimester.

Only one woman with antibodies to SARS-CoV-2 had a pregnancy loss. The physicians also obtained data from 36 women with a first-trimester pregnancy loss, but none had COVID-19.

“Other infectious diseases may negatively affect both the mother and the fetus, such as measles or severe flu, but COVID-19 does not appear to have the same harmful effect on the fetus. The conclusion of this part of the study is that COVID-19 does not increase the risk of harming the fetus during the first trimester,” says Henriette Svarre Nielsen.

No additional complications among pregnant women with COVID-19

In the second part of the study, the researchers aimed to determine whether COVID-19 negatively affected obstetric complications, including the risk of caesarean section or complications in the later stages of pregnancy.

Here, too, the researchers found no difference in the risk of caesarean section, premature birth, preeclampsia, placental abruption or the baby’s Apgar score, birthweight, umbilical cord pH, need for breathing support and admission to the neonatal ward.

Conversely, they found that, if the mother had COVID-19, the baby also often had antibodies to SARS-CoV-19 and was therefore probably protected against it.

“The result is not surprising, but confirming it is good, since other infectious diseases affect both the pregnant woman and the fetus. This applies to Middle East respiratory syndrome, severe acute respiratory syndrome and other diseases. Therefore, this cannot be ruled out until it has been investigated,” explains Henriette Svarre Nielsen.

More results on the way

Henriette Svarre Nielsen explains that the first published results from the study are just part of the research into the possible links between COVID-19 and pregnancy.

The physicians included 5,400 active participants and 35,000 samples stored in the Copenhagen Hospital Biobank. These include samples taken in the second and third trimesters and placenta biopsies and breast-milk, which the researchers will examine.

The researchers also plan to determine how COVID-19 affects the immune systems of both the pregnant women and the newborns.

“We are conducting numerous in-depth investigations, and these are just the first results,” says Henriette Svarre Nielsen.

The world’s most interesting research

Henriette Svarre Nielsen’s research not only focuses on determining whether COVID-19 affects pregnant women or their newborns but will also improve understanding of what can go wrong during pregnancy.

In parallel with the COVID-19 project, the researchers and physicians from Hvidovre Hospital are working on a large research project called Copenhagen Pregnancy Loss Cohort supported by the BioInnovation Institute as a faculty project. The researchers want to determine the underlying cause of all the pregnancy losses identified by the physicians at Hvidovre Hospital.

Twenty-five percent of all pregnancies are lost. Although this happens so frequently, physicians know incredibly little about the underlying mechanisms. Many losses result from genetic defects, but very little is known about whether the genetic defects result from conditions among the father or mother or whether something different is involved. Today, physicians only examine couples when they have experienced at least three consecutive pregnancy losses.

“This is a huge study examining the genetics of the couples and the fetuses and lifestyle factors among both men and women including smoking, alcohol, weight, exercise, the immune system, hormones, endocrine disruptors and the microbiome. We also have sperm samples from the men to investigate whether semen factors can causepregnancy loss. Frankly speaking, the Copenhagen Pregnancy Loss Cohort is currently one of the world’s most interesting research projects,” says Henriette Svarre Nielsen.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies at delivery in women, partners, and newborns” has been published in Obstetrics & Gynecology. “SARS-CoV-2 in first trimester pregnancy: a cohort study” has been published in Human Reproduction. Employees of the Novo Nordisk Foundation Center for Protein Research participated in the studies. In 2016, the Novo Nordisk Foundation awarded a Novo Nordisk Foundation Young Investigator Grant to co-author Eva Hoffmann.

Expertises (Recurrent) Pregnancy Loss; Infertility; women’s health Main research areas Reproductive and female “omics”, immunology, epidemiology...

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