User:Kvauls/Infant mortality

Leading Causes of Infant Mortality
There are three main leading causes of infant mortality; namely Premature-related conditions, Congenital anomalies and Sudden Infant Death Syndrome. In North Carolina,Premature-related conditions ranked first, with a percentage of 37.5%, followed by congenital anomalies which accounted for 17.4% of the total infant deaths, while Sudden Infant Death Syndrome accounted for 12.9%.

Premature birth
Premature, or preterm birth (PTB) is defined as birth before 37 weeks of gestation and can be further sub-classified as extremely PTB (occurring at less than 28 weeks gestation), very preterm birth (occurring between 28 and 32 weeks gestation), and moderate to late PTB (occurring from 32 through 36 weeks gestation). Lower gestational age increases the risk of infant mortality.

Over the last decade, prematurity has been the leading cause of worldwide mortality for neonates and children under the age of five. The overall PTB mortality rate in 2010 was 11.1% (15 million deaths) worldwide and was highest in low to middle-income countries in sub-Saharan Africa and south Asia (60% of all PTBs), compared with high-income countries in Europe, or the United States. Low-income countries also have limited resources to care for the needs of preterm infants, which increases the risk of infant mortality. The survival rate in these countries, for infants born before 28 weeks of gestation is 10%, compared with a 90% survival rate in high-income countries. In the United States, the past two decades of the 20th centuary has seen a significant increase in Premature births,despite a decrease in the total number of infant mortality cases.

Based on distinct clinical presentation there are three man subgroups of preterm births; those that occur due to spontaneous premature labor, those that occur due to spontaneous membrane (Amniotic sac) rapture, and those that are medically induced. Both spontaneous are viewed to be a result of similar causes, hence two main classifications remain: spontaneous and medicalyl induced causes. The risk of spontaneous PTB increases with "extremes of maternal age (both young and old), short inter-pregnancy interval, multiple gestations, assisted reproductive technology, prior PTB, family history, substance abuse, cigarette use, low maternal socioeconomic status, late or no prenatal care, low maternal pregnancy weight, bacterial vaginosis, periodontal disease, and poor pregnancy weight gain." Medically induced PTB is often conducted when continued pregnancy poses significant risks to the mother or fetus. The most common attributing factors for medically induced PTB include preeclampsia, diabetes, maternal medical conditions, fetal distress, or developmental problems. Despite these risk factors, the underlying causes of premature infant death are often unknown and approximately 65% of all cases are not associated with any known risk factor.

Understanding the biological causes and predictors is important for identifying and preventing premature birth and infant mortality. While the exact mechanisms responsible for inducing premature birth are often unknown, many of the underlying risk factors are associated with inflammation. Additionally, understanding the risks associated with different gestational ages is a helpful determiner of gestational age-specific mortality. The rate of infant mortality in preterm births of gestational age above 26- 1weeks are significantly lower compared to those under the same age. Approximately "80% of preterm births that occur at <1000 g or at <28 to 30 weeks of gestation" have been associated with inflammation. Biomarkers of inflammation, including C-reactive protein, ferritin, various interleukins, chemokines, cytokines, defensins and bacteria have been shown to be associated with increased risks of infection or inflammation-related preterm birth. Biological fluids have been utilized to analyze these markers in hopes of understand the pathology of preterm birth, but are not always useful if not acquired at the appropriate gestational time-frame. For example, biomarkers such as fibronectihn are accurate predictors of premature birth at over 24 weeks gestation, but have a poor predictive values before then.

Infant mortality caused by premature birth is mainly attributed to the various complications of preterm births. A key characteristic of preterm birth is developmental immaturity, which directly impacts different organ systems of the infant's body. Main body systems affected include the respiratory system, which due to failure of fetal breathing movement may result in pulmonary hypoplasia, Respiratory Distress Syndrome, Bronchopulmonary Dysplasi a and Chronic Lung Disease, and apnea. Other body systems that rely on later gestational age to be fully developed include, the gastrointestinal system, the skin, the Immune System, Cardiovascular System, Hematologic System. Poor development of these body systems increase the risks of infant mortality.