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Mortality and Morbidity

Infant mortality is defined as death occurring during the first year of life. In the United States, approximately 20,000 babies die each year from causes including birth defects, preterm birth and sudden infant death syndrome. In addition to giving us key information about maternal and infant health, the infant mortality rate is an important marker of the overall health of a society.* Neonatal mortality is typically associated with events surrounding the prenatal period and the delivery, whereas post neonatal deaths are more likely to be associated with conditions or events that arise after the delivery and may reflect environmental factors.

Maternal mortality is defined as the death of a woman while pregnant or within 42 days of the termination of a pregnancy, from any cause related to or aggravated by pregnancy or its management, but not due to accidental or incidental causes of death.** From 2018 to 2021, 870 maternal deaths occurred each year, on average3 and every year 50,000 women experience a life-threatening complication (sometimes called a “near-miss”) or severe maternal morbidity. High rates of maternal morbidity or mortality indicate inequalities in access to quality health services and can highlight disparities between different populations.4

Measures of mortality and morbidity provided on PeriStats include:

  • Late fetal mortality (28 or more weeks of gestation) and perinatal mortality (fetal deaths of 28 or more weeks gestation and infant deaths in the first 7 days of life)
  • Infant mortality, including neonatal mortality (0-27 days) and post neonatal mortality (28 days – under 1 year)
  • Causes of infant death
  • Maternal mortality
  • Severe maternal morbidity

1. Centers for Disease Control and Prevention. Infant mortality. Available at:

2. World Health Organization. International statistical classification of diseases and related health problems, 10th revision (ICD–10). 2008 ed. Geneva, Switzerland. 2009.

3. Centers for Disease Control and Prevention. Maternal Mortality Rates in the United States, 2021. Available at:

4. World Health Organization. Maternal mortality. Available at:

Last updated: February 2024