Dallas Researchers Have More Good News for Pregnant People With Covid-19

A new study from Dallas scientists shows encouraging outcomes for moms

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Pregnant women around the world are scared about catching Covid-19 and passing it on to their babies. Obstetricians, like me, work to protect our patients and keep them safe, but much remains unknown about the novel coronavirus’s effects on pregnant people and babies.

A new paper published in the medical journal JAMA offers more encouraging news for pregnant people. Researchers at the University of Texas Southwestern Medical Center in Dallas published a study titled Pregnancy Outcomes Among Women With and Without Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

The results show that 95% of women who tested positive for Covid-19 during pregnancy had no adverse outcomes. Only five percent of infected women experienced severe complications such as pneumonia and respiratory distress.

This study also showed a low rate of newborn infections (3%). Previously published data from the PRIORITY Study (Pregnancy Coronavirus Outcomes Registry) showed babies born to Covid-19 positive people do well with no increase in negative metrics such as low birth weight, difficulty breathing, apnea, or respiratory infections through the first eight weeks of life.

Based on the current scientific understanding of Covid-19 infection in pregnancy, there is no evidence at this time indicating pregnant women are more at risk for severe illness from Covid-19 than the general public. In general, viral infections in pregnancy can lead to poor outcomes in mothers and newborns. Pregnant women are not more at risk of contracting Covid-19 than the general public, but they are at a higher risk of getting sick from the virus.

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During pregnancy, women have a temporarily suppressed immune system and physiologic changes in their lung function. These changes put pregnant people at higher risk of respiratory problems when they contract similar viruses, such as influenza or pneumonia. OB-GYNs, therefore, consider pregnant women to be an at-risk group for respiratory compromise if they contract Covid-19.

Additionally, preterm labor is a known risk when pregnant women contract viral illnesses such as MERS, SARS, and influenza. Preterm labor most likely results from the severity of the maternal illness. Preterm labor is not directly linked to the virus itself. In other words, preterm labor is not simply a result of contracting these viruses but rather dependent on the degree of illness that results.

This paper from Dallas-based UTSW adds to the growing body of medical evidence that most women who contract Covid-19 will do well. The authors acknowledge the scientific consensus that viral infections place pregnant people at risk but highlight the low number of sufficiently powered, large-scale studies conducted to accurately assess the specific risks associated with SARS-CoV-2. The purpose of this study was to address this gap in scientific research.

This large urban county health system’s research compared outcomes in 252 SARS-CoV-2-positive and 3,122 negative pregnant women. The data was collected from March 18 through August 22, 2020. The study population included 2,520 Latinx (75%), 619 Black (18%), and 125 White (4%) women. The statistical analysis controlled for variables such as age, parity, body weight, and other medical conditions.

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The study found SARS-CoV-2 positivity was more common in Latinx women, accounting for 90% of the cases. Latinx women make up 75% of the 12,000 women delivering at UTSW.

Thirteen women (5%) developed severe respiratory complications requiring interventions, and one patient developed venous thromboembolism.

There was no difference in preterm birth rates, preeclampsia, C-section rates, or stillbirth in women with Covid-19. This data is further supportive evidence that pregnant women who test positive for Covid-19 and their newborn babies have a low risk of developing severe symptoms.

This study also evaluated the placenta for evidence of pathological changes. Scientists have been concerned the viral illness could lead to placental vasculopathy and inflammatory infiltrates. Pathologists studied the placentas of patients infected with Covid-19. This study found the majority were not affected by the virus.

NIH research indicates that in utero mom-to-baby transmission is rare because the placenta is missing key components the virus needs to enter the fetal circulation, namely ACE2 receptors and the TMPRSS2 enzyme. Both the ACE2 receptor and TMPRSS2 are present in the placenta but only in tiny amounts. The low levels likely explain why SARS-CoV-2 is unlikely to cross the placenta from mom to baby.