Contemporary medical understanding of the'no-fault accident' during birth: Amniotic fluid embolism, pulmonary embolism, meconium aspiration syndrome, and cerebral palsy

Although every pregnant woman and her physician hope for an easy pregnancy free of complications, complications can occur to a greater or lesser extent, some of which are still considered inevitable. The maternal mortality ratio in the Republic of Korea recently increased from 13.5 per 100,000 live births in 2009 to 17.2 in 2011, along with a noticeable increase, of up to 20%, in the proportion of older pregnant women (>35 years old). In contrast to postpartum bleeding, which has decreased, amniotic fluid embolism and pulmonary embolism, which are closely related to older maternal age and typically considered inevitable, are causing an increasing proportion of maternal mortalities. The neonatal mortality rate, defined the rate of death per 1,000 live births under 28 days of life, was reported to be 1.7 in 2011 in Korea and respiratory distress of newborns accounts for about one third of neonatal deaths. The prevalence of cerebral palsy (CP) is approximately 2 per 1,000 live-born children and has remained unchanged over recent decades worldwide. Although multiple antenatal factors, including preterm birth, low birth weight, infection/inflammation, multiple gestation, and other pregnancy complications have been frequently associated with CP, the underlying causes of CP remain largely unknown and recent evidence has indicated that birth asphyxia plays a minor role. This review provides information on the contemporary medical understanding of amniotic fluid embolism, pulmonary embolism, meconium aspiration syndrome, and CP, which are generally considered to be 'no-fault accidents' during birth.