Coronavirus infections may be more frequent in pregnant women than in the general population, and those who contract the virus could also be more susceptible to acute respiratory distress syndrome. 

By Lisa Spear

When a woman is pregnant, a myriad of physiological changes take hold in the respiratory system. The breath becomes shallow, and rapid as the gravid uterus encroaches on the diaphragm.

Even during normal pregnancy, the pressure from the growing fetus can cause shortness of breath. Lung capacity decreases. A woman’s immune system becomes suppressed and the airway fundamentally changes during pregnancy making her more vulnerable to respiratory problems, including more severe complications due to the novel coronavirus, SARS-CoV-2.  

“There’s oropharyngeal swelling that occurs just from being pregnant. Every pregnant woman is swollen and it’s not just her feet, but the airway gets swollen, too,” said critical care obstetrician Corrina Oxford-Horrey, MD, the director of labor and delivery of maternal and fetal medicine at Weill Cornell Medical Center. 


During pregnancy, there is more atelectasis, a complete or partial collapse of the lung or part of the lung. There’s a decrease in functional residual capacity, the volume remaining in the lungs following a passive exhalation. All of these changes affect the threshold for intubation and mechanical support for the pregnant patient. Pregnant women who contract the virus could also be more susceptible to acute respiratory distress syndrome (ARDS). 

ARDS is a common cause of respiratory failure in critically ill patients. Characterized by fluid buildup in the lung’s alveoli, ARDS prevents the lungs from filling with enough air and less oxygen reaches the bloodstream. A complication in up to 33% of COVID-19 patients, a large percentage of ARDS result in death.1-2 While there is still limited data on how ARDS manifests in pregnant COVID patients, many case reports show that illness can be dire. The Centers for Disease Control and Prevention (CDC) said pregnant women are at a higher risk for death and severe disease.

“When something like COVID is affecting the immune system in the pregnant patient, she might have more severe disease,” said Oluwatosin Goje, MD, an obstetrician/gynecologist and reproductive infectious diseases specialist at the Cleveland Clinic in Ohio. 

Coronavirus infections may also be more frequent in pregnant patients than in the general population. A recent report from the CDC found that one in four women aged 15 to 49 years who had a COVID-19–related emergency room visit between March 1 and August 22, 2020, was pregnant, based on a sample from COVID-NET, a population-based surveillance system monitoring COVID-19-associated hospitalizations. The report showed that among symptomatic pregnant women, 16.2% were admitted to an intensive care unit, while 8.5% needed mechanical ventilation. 

Despite the obstacles presented by the coronavirus, healthcare providers have seen success in stabilizing these patients through established respiratory therapy techniques, including the administration of mechanical ventilation, extracorporeal membrane oxygenation (ECMO), and in some cases placing the woman in a prone position to increase oxygenation.3 Clinicians also report that noninvasive options, including bilevel positive airway pressure (BiPAP), and high flow nasal cannula (HFNC), may help to prevent intubation. 

Depending on the gestational age of the fetus, cases of severe ARDS in pregnant women may call for early delivery via a cesarean section. A recent report from the CDC that looked at approximately 600 hospitalized pregnant women with COVID-19 found that 12.6% of births were earlier than 37 weeks, a higher percentage of preterm births than what is seen in the general population. 

“Preterm birth is the biggest risk that we worry about. If the baby is not getting adequate oxygenation, then you may need to deliver, under controlled circumstances because of the fetal condition,” said Oxford-Horrey.

Early delivery should be considered carefully with an interdisciplinary team, said Goje. In one instance, Goje cared for a woman in her early 30s who came to the emergency room with shortness of breath and COVID pneumonia. 

Previous chest radiograph showed patchy ground-glass opacities in her lungs. Repeat imaging showed a bilateral alveolar ground-glass pattern. Despite being placed on HFNC, her condition decompensated, her oxygen levels continued to drop, and the critical care team decided to go through with an emergency cesarean section. In this case, the baby died due to complications related to prematurity, while the mother recovered and was discharged from the hospital a few days later. 

“Many times, delivery helps when we have very sick patients who are intubated,” said Goje. “If every effort has been made from the critical care team and the pulmonologist to help the patient who is ventilated and nothing is working, you start looking at delivery.”

A recent retrospective observational study on pregnant women with COVID-19 found that 4 out of 7 nonintubated patients in respiratory distress had a substantial increase in oxygen saturation within hours to days after delivery, possibly due to uterine decompression improving the patient’s ability to breath.5

In a case report, published in Respiratory Medicine Case Reports, a 41-year-old pregnant patient who was critically ill with COVID-induced ARDS saw a sharp improvement in oxygenation after delivery.6

“The dramatic improvement in her oxygenation and plateau pressures post-delivery suggests that uterine decompression and improved lung compliance may have been a significant contributing factor,” the authors wrote. “The rapid liberation from the ventilator despite the severity of her illness supports this, as well. We suggest that delivery should be strongly considered as part of the management of critically ill COVID-19 patients who develop rapidly worsening ARDS.”

However, even if a pregnant COVID-positive woman has refractory hypoxemia, preterm delivery might not be necessary, said Oxford-Horrey. She advises that clinicians should focus on stabilizing the mother. Intubation does not need to lead to preterm birth, she said. 

To minimize harm, the Society for Maternal-Fetal Medicine does not recommend early delivery because there is not enough evidence to show improvement in lung function attained by early birth.7

“I can tell you that I have taken care of a lot of sick women with ARDS and it can be very tempting to deliver, but you often just have to hold off,” said Oxford-Horrey. 

She suggests using noninvasive alternative interventions first, including HFNC. In patients with acute hypoxaemic respiratory failure, HFNC can help avoid intubation when compared to conventional oxygen devices.8-9

High flow also provides some positive end expiratory pressure (PEEP), which counteracts atelectasis in women who are in their third trimester or beyond, Oxford-Horrey said. 

Some providers have decreased the use of high-flow due to concerns about the potential spread of the coronavirus into the environment. This risk can be mitigated with a surgical mask placed over the patient’s face, an associate professor in Rush University’s Division of Respiratory Care, Jie Li, PhD, RRT, and colleagues wrote in the European Respiratory Journal.10

Additionally, proning is another technique that healthcare providers may find helpful in supporting oxygenation in COVID-positive pregnant women. With proning clinicians can position a woman’s body to increase her ability to breathe, while supporting her hips to avoid abdominal compression, according to a paper published in the American Journal of Perinatology.11

Depending on how far along the woman is in her pregnancy, the proning technique can be performed with pillows or other props to support the woman and keep pressure off the belly. If positioned with care, this technique can even be done in the third trimester, coauthor Oxford-Horrey said. 

Overall, many of the respiratory care techniques deployed for all ARDS patients can be safely used in pregnant women who are experiencing severe COVID-19. 

“If you are dealing with pregnant COVID patients with ARDS, maternal stabilization should be prioritized above all else,” Oxford-Horrey said. “If you improve the maternal status, the fetus benefits.”


RT

Lisa Spear is associate editor of RT. For more information, contact [email protected]



References

  1. Michael AM, et al. Acute respiratory distress syndrome. Nat Rev Dis Primers. 2019 Mar 14;5(1):18. 
  2. Rodriguez-Morales AJ, et al. Clinical, laboratory and imaging features of COVID-19: a systematic review and meta-analysis. Trav Med Infect Dis. 2020;34:101623. doi: 10.1016/j.tmaid.2020.101623. 
  3. Barrantes J, et al. Successful Treatment of Pregnant and Postpartum Women With Severe COVID-19 Associated Acute Respiratory Distress Syndrome With Extracorporeal Membrane Oxygenation. ASAIO J. 2021 Feb 1;67(2):132-136. 
  4. McLaren RA, et al. Delivery for respiratory compromise among pregnant women with COVID-19. Am J Obstet Gynecol. 2020.
  5. Chong J, et al. Acute Respiratory Distress Syndrome in a pregnant patient with COVID-19 improved after delivery: A case report and brief review. Respir Med Case Rep. 2020; 31: 101171. 
  6. Society for maternal-fetal medicine management considerations for pregnant patients with COVID 19. https://s3.amazonaws.com/cdn.smfm.org/media/2401/SMFM_COVID_Management_of_COVID_pos_preg_patients_6-16-20._PDF.pdf.
  7. Rochwerg B, Granton D, Wang DX, et al. High flow nasal cannula compared with conventional oxygen therapy for acute hypoxemic respiratory failure: a systematic review and meta-analysis. Intensive Care Med 2019; 45: 563–572.
  8. Li J, et al. Year in review 2019: high-flow nasal cannula oxygen therapy for adult patients. Respir Care. 2020;65:545–557.
  9. Jie Li, et al. High-flow nasal cannula for COVID-19 patients: low risk of bio-aerosol dispersion. ERJ. 2020;55:2000892.
  10. Oxford-Horrey C, et al. Putting It All Together: Clinical Considerations in the Care of Critically Ill Obstetric Patients with COVID-19. Am J Perinatol. 2020 Aug;37(10):1044-1051.