COVID-19 During Pregnancy

With baseline immune system, heart and lung stressors, expectant mothers have added vulnerabilities to complications from SARS-CoV-2 illness.

Recent clinical data suggest that pregnancy exacerbates SARS-CoV-2 complications. Expectant mothers face stressors to the immune system and to the lungs and heart that increase vulnerability to COVID-19 illness. “Pregnant patients most at risk to have a severe outcome during pregnancy are those with obesity, diabetes and hypertension. For lab specialists, it would be important to know if these pathologies are present.

Several factors may play a role in the virus’ pathophysiology and clinical course in pregnant women. This includes an increased sensitivity to hypoxemia due to anatomical and physiological changes associated with pregnancy, risk of pulmonary (and placental) microvascular thrombosis, and an impaired immune function leading to a possibly unfavorable inflammatory response.

Pregnant women with the virus are at risk for experiencing pre-term births, according to a new BMJ report of 77 studies that included more than 11,000 pregnant and recently pregnant women admitted to the hospital and diagnosed with confirmed or suspected SARS-CoV-2. Infected pregnant women are also more likely to end up in the ICU, according to the BMJ report and others. One study that compared ICU admission rates between pregnant and non-pregnant infected patients in Sweden found that pregnant women and postpartum women had a nearly six-fold greater chance of admission, according to this news report. Similarly, the U.S. Centers for Disease Control and Prevention (CDC) reported that among more than 91,000 infected women of reproductive age, pregnant individuals had higher ICU admissions (1.5%) compared to nonpregnant women (0.9%). They also needed mechanical ventilation more often (0.5%) compared with 0.3% of nonpregnant women.

In calculating its data, CDC “didn’t divide out hospitalizations that would be expected for delivering a baby from hospitalizations related to illness,” noted Diana Bianchi, MD, in a recent Q&A with Francis Collins, MD, PhD, director of the National Institutes of Health (NIH). “But the report did show that pregnant women are at a higher risk of needing respiratory support and having serious illness, particularly if there is an underlying chronic condition, such as chronic lung disease, diabetes or hypertension,” added Bianchi, director of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Compared to other upper respiratory illnesses such as H1N1 influenza, risk of ICU admission and mechanical ventilation remains low for pregnant women, the American College of Obstetricians and Gynecologists (ACOG) observed in its analysis of the CDC data. ACOG noted that Black or Hispanic women had a higher infection risk. Additionally, ICU admission was more common in non-Hispanic Asians (3.5%) compared to all pregnant women (1.5%). “ACOG is reviewing all of our clinical materials and patient resources related to COVID-19 in light of newly available information and will make any necessary revisions to recommendations.”