Study: The Impact of Coronavirus on Pregnant Women

June 16, 2020 | by Brenda Simpler
Study: The Impact of Coronavirus on Pregnant Women

In January, as Washington State began seeing the first cases of COVID-19 emerge, several Obstetrix-affiliated clinicians, Jeroen Vanderhoeven, MD, Bettina W. Paek, MD, Carolyn R. Kline, MD, MPH, in collaboration with the University of Washington set out to document and study the impact of the coronavirus on pregnant women. Through the first three months of 2020, Swedish Medical Center and Evergreen Health Medical Center became two of the hospitals responsible for treating one of the largest cluster of cases in the country.

Moving into the unknown

Given that little was known about the virus’ transmission, treatment or how to most effectively provide care to pregnant women and their babies, quickly gathering and sharing data about how the virus impacted this population was critical to establishing effective care and treatment protocols. As the largest provider of Women’s and Children’s services, across multiple specialties, Obstetrix is uniquely positioned for enhanced collaboration and information sharing.

“We were fortunate to have the support of a large team to gather this information quickly and make it available for publication early in the pandemic. We hope our experience will aid others in counseling, reassurance and care management of COVID-19 in pregnancy,” said Dr. Vanderhoeven.

Summary of findings

The study authors, Dr. Vanderhoeven, Dr. Bettina and Dr. Kline, reported on a case series of 46 pregnant patients with COVID-19 from six large hospital systems in Washington State from a time period when patients were being tested mainly after presenting with symptoms. Of the 46 COVID positive pregnant patients included in the study, three were asymptomatic and 43 presented with symptoms. In the 43 symptomatic patients, one in seven pregnant patients with COVID-19 were hospitalized for respiratory concerns and one in eight had severe COVID-19 symptoms.

Washington State (3)


Pregnant patients with severe COVID-19 were noted to be overweight or obese prior to pregnancy and many had additional comorbidities, including asthma and hypertension. Obesity as a risk factor for severe COVID-19 in pregnancy is particularly concerning as the national prevalence of obesity has been increasing, most recently 39.7% among women of reproductive age (20–39 years old) in 2017-2018. Obesity is known to impair lung function through both mechanical and inflammatory pathways. A synergistically detrimental impact on maternal lung function may occur among women with multiple risk factors such as a COVID-19, pneumonia, obesity, asthma and the added mechanical stress of an enlarged uterus in third trimester pregnancy.

During the study period, eight (17.4%) patients delivered, including seven live births and one stillbirth. The median number of days between a positive SARS-CoV-2 test and delivery was 7.5 days (IQR 5.0-11.5). The median gestational age at delivery was 38.4 weeks (IQR 37.5-39.8). In one case, worsening respiratory status and multiple comorbidities, including Class III obesity, led to the decision to deliver the patient preterm at 33 weeks’ gestation. Of the eight deliveries, five (62.5%) were vaginal and 3 (37.5%) were cesarean delivery. Find the full, published study here.

Commitment to research

Said Kimberly Maurel, MSN, CNS, RN, Associate Director of The Center for Research, Education, Quality & Safety, “These important results highlight the need to consider classifying pregnant women as one of the high-risk COVID-19 groups along with elderly and those with comorbidities”

In May, at the conclusion of the study, the data suggests that nearly 15% of pregnant patients could develop severe COVID symptoms. Pregnant patients should be treated with the same high-risk precautions as other identified high-risk groups, including the elderly, patients with diabetes, asthma or other comorbidities. Dr. Vanderhoeven, Dr. Paek and Dr. Kline will continue to collect data on new patients, bringing more attention to pregnant patients as a high-risk group. As part of MEDNAX’s commitment to research and collaboration, they will work to share treatment protocols that work towards improving outcomes for pregnant women with the coronavirus.  

The MEDNAX Center for Research, Education, Quality and Safety (CREQS) empowers health care providers to take great care of the patient, every day and in every way. As part of our ongoing commitment to improving patient care through evidence-based medicine, we engage in clinical research, education, continuous quality improvement and safety initiatives. Our efforts contribute to better patient outcomes and reduced long-term health system costs, not only for our patients and hospital partners but for all patients and providers across our specialty areas.


Clinically reviewed by Jeroen Vanderhoeven, MD