Mortality differs by year, geography in critically ill pregnant women
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Key takeaways:
- A small percentage of patients deemed critically ill were pregnant.
- Most in-hospital deaths of critically ill pregnant patients occurred in the East South Central census division.
Among pregnant women with critical illnesses, in-hospital mortality rates fluctuated by year and geographic location, according to a research letter published in Annals of the American Thoracic Society.
“While uncommon, we do encounter pregnant patients who receive invasive mechanical ventilation and/or develop septic shock and the volume of such patients may be impacted by external factors (ie, the H1N1 influenza pandemic of 2008-2009 and the COVID-19 pandemic in 2020-2021),” Hayley B. Gershengorn, MD, FCCM, ATSF, professor in the division of pulmonary, critical care and sleep medicine at University of Miami’s Miller School of Medicine, told Healio. “Moreover, despite being relatively young and healthy at baseline, a sizeable percentage of pregnant women with these critical illnesses die.”
In a retrospective cohort study that used 2008 to 2021 data from the Premier Healthcare Database, Gershengorn and colleagues assessed 416,405 female patients who received mechanical ventilation and 221,458 female patients with septic shock to determine pregnancy and mortality rates across different years and census divisions.
Notably, each set of patients included pregnant individuals who received mechanical ventilation (n = 8,670) and pregnant individuals with septic shock (n = 4,080).
More pregnant patients who received mechanical ventilation died in the hospital than patients who suffered with septic shock (7.8% vs. 5.1%).
“The relatively high rates of death by hospital discharge among pregnant women, who are generally young and without significant comorbidity, was surprising,” Gershengorn told Healio. “I had not expected 1 in 13 pregnant patients receiving mechanical ventilation and 1 in 20 with septic shock to die given their relative baseline health.”
Pregnancy, mortality rates by year
Following adjustment for hospital census division, teaching status, urbanicity and the number of hospital beds, researchers reported significant variation when evaluating pregnancy and mortality rates across 2008 and 2021.
When compared with 2012, which had the lowest rates for both outcomes in those receiving mechanical ventilation, years with elevated odds for pregnancy in critically ill patients included 2009, 2013, 2016, 2017, 2020 and 2021. Among pregnant mechanically ventilated patients, the odds for mortality rose in 2008, 2017 and 2021.
Among pregnant patients with septic shock, the year with the lowest mortality rate was 2018. Compared with this year, several years had significant differences in pregnancy rates: 2008, 2009, 2010, 2011, 2012, 2013, 2020 and 2021. Researchers further found a heightened likelihood for mortality among pregnant patients with septic shock in 2009, 2010, 2013, 2015 and 2021.
Pregnancy, mortality rates by geography
Pregnancy rates within the nine census divisions differed among those receiving mechanical ventilation (1.4%-2.8%) and those with septic shock (1.5%-3.1%), according to researchers.
In terms of mortality rates, researchers found the most in-hospital deaths of pregnant patients receiving mechanical ventilation in the East South Central census division (adjusted rate, 12.4%; 95% CI, 8.7%-16%) and the least deaths in the New England division (adjusted rate, 5%; 95% CI, 0.8%-9.3%).
Similarly, the division with the most deaths of pregnant patients with septic shock was the East South Central division (adjusted rate, 7.8%; 95% CI, 4.6%-11.1%), whereas the New England division had the least deaths (adjusted rate, 2.5%; 95% CI, –0.8% to 5.8%).
Future studies
When asked about future studies, Gershengorn expressed her concerns over possible growth of this patient population in the U.S. due to the “changing landscape of access to reproductive health care.”
“Pregnant people who might otherwise have chosen termination due to severe underlying chronic health conditions may now be unable to do so; such patients certainly have higher risk for maternal morbidity and mortality,” she told Healio.
“Additionally, pregnant patients who present with acute illnesses (either related to their pregnancy, such as premature rupture of membranes, or unrelated but likely exacerbated by pregnancy, such as acute lung injury from influenza) may be less likely to receive urgent termination allowing them to progress to or have worsening of their already existing critical illness,” she continued.
Less access to reproductive health care may also lead to more women trying to terminate their pregnancies by themselves, which can put them at risk for critical illnesses, Gershengorn said.
“As these patients will likely be sicker at baseline than our current critically ill pregnant patients and our ability to provide one of the optimal and time-sensitive treatments of their acute condition (eg, termination) may be reduced, I worry that mortality rates will rise as well,” Gershengorn told Healio.
According to Gershengorn, evaluating how legislative changes impact rates of critical illnesses among pregnant women “is of paramount importance.”
“We know that maternal mortality rates vary in the U.S. in ways that are not justifiable medically (eg, by race),” she said. “We must be vigilant to ensure disparities that arise or widen across state lines be identified and addressed.”