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Cosmos Study

Increased Risk of NICU Admission and Neonatal Mortality Associated with Maternal Comorbidities, Race, and Age

November 30, 2023
Dual-Team Study
Team A:Matthew Gracianette, MDNeil Sandberg
Team B:Kersten Bartelt, RNRobert S. HooverEric Barkley

Key Findings

  • Babies born to mothers who had hypertension or gestational diabetes, or who were over age 40 had the greatest risk of being admitted to the NICU. 
  • Babies born to mothers who are Black, who have a higher social vulnerability index (SVI), or who were over age 40 had the greatest risk of neonatal mortality. 

The Centers for Disease Control and Prevention (CDC) considers infant mortality one of the overall indicators of a society’s health.1 To better understand what risk factors are most correlated with neonatal mortality and conditions requiring neonatal intensive care, we studied 3,207,461 infants born between January 1, 2016, and June 30, 2023. In our model we adjusted for maternal hypertension, gestational diabetes, maternal age, SVI, drug use, maternal or infant infections, maternal autoimmune conditions, and marital status.  

We found that babies born to mothers diagnosed with hypertension or gestational diabetes during pregnancy had 111% and 55% greater odds of being admitted to the NICU than those born to mothers without those diagnoses, respectively. Babies born to mothers over age 40 had 40% greater odds of being admitted to the NICU than those born to mothers ages 20-29. Lastly, babies born to mothers in the highest SVI percentile had 26% greater odds of being admitted than those born to mothers in the lowest SVI percentile. 

Figure 1
Relative Likelihood of NICU Admission by Maternal Characteristic
Relative Likelihood of NICU Admission by Maternal Characteristic
Figure 1. The relative likelihood of a baby being admitted to the NICU by maternal characteristic.

When evaluating increased risk for neonatal mortality, we found that babies born to Black women had 94% greater odds of mortality than babies born to White mothers. Babies born to mothers in the highest SVI percentile had 80% greater odds of neonatal mortality than those born to mothers in the lowest SVI percentile. Babies born to mothers over age 40 had 72% greater odds of mortality than those born to mothers aged 20-29. 

Figure 2
Relative Likelihood of Neonatal Death by Maternal Characteristic
Relative Likelihood of Neonatal Death by Maternal Characteristic
Figure 2. The relative likelihood of neonatal death by maternal characteristic. 

A sensitivity analysis using Area Deprivation Index (ADI) instead of SVI found similar trends. For NICU admissions, the greatest factors in this model were hypertension, ADI decile, and gestational diabetes. For neonatal mortality, the greatest factors in this model were ADI decile, maternal race of Black, and maternal age over 40.  

These data come from Cosmos, a collaboration of 222 Epic health systems representing over 220 million patient records from 1,272 hospitals and more than 27,200 clinics from all 50 states and Lebanon. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Brian Olson.    

References

  1. Infant mortality. (2023, September 19). Cdc.gov. https://www.cdc.gov/reproductivehealth/maternalinfanthealth/infantmortality.htm