infant mortality infant mortality infant mortality is the death of an infant before the infant's first birthday. the occurrence of infant mortality in a population can be described by the infant mortality rate (imr), which is the number of deaths of infants under one year of age per 1,000 live births. similarly, the child mortality rate, also known as the under-five mortality rate compares the death rate of children up to the age of five. world map of infant mortality rates in 2017 in 2013, the leading cause of infant mortality in the united states was birth defects. other leading causes of infant mortality include birth asphyxia, pneumonia, congenital malformations, term birth complications such as abnormal presentation of the fetus umbilical cord prolapse, or prolonged labor, neonatal infection, diarrhea, malaria, measles, and malnutrition. one of the most common preventable causes of infant mortality is smoking during pregnancy. lack of prenatal care, alcohol consumption during pregnancy, and drug use also cause complications which may result in infant mortality. many situational factors lead to infant mortality, such as the pregnant woman's level of education, environmental conditions, political infrastructure, and level of medical support. improving sanitation, access to clean drinking water, immunization against infectious diseases, and other public health measures can help reduce high rates of infant mortality. in 1990, 8.8 million infants younger than 1-year-old died globally out of 12.6 million child deaths under the age of five. more than 60% of the deaths of children under-five are seen as being avoidable with low-cost measures such as continuous breastfeeding, vaccinations, and improved nutrition. the global mortality rate in 1950 was 22.5% which dropped to 4.5% in 2015. over the same period, the infant mortality rate declined from 65 deaths per 1,000 live births to 29 deaths per 1,000. globally, 5.4 million children died before their fifth birthday in 2017. the child mortality rate, but not the infant mortality rate, was an indicator used to monitor progress towards the fourth goal of the millennium development goals of the united nations for the year 2015. a reduction in child mortality is now a target in the sustainable development goals—goal number 3: ensure healthy lives and promote well-being for all at all ages. throughout the world, the infant mortality rate (imr) fluctuates drastically, and according to biotechnology and health sciences, education and life expectancy in the country is the leading indicators of imr. this study was conducted across 135 countries over the course of 11 years, with the continent of africa having the highest infant mortality rate of any region studied, with 68 deaths per 1,000 live births. classification infant mortality rate (imr) is the number of deaths per 1,000 live births of children under one year of age. the rate for a given region is the number of children dying under one year of age, divided by the number of live births during the year, multiplied by 1,000. forms of infant mortality: perinatal mortality is late fetal death (22 weeks gestation to birth) or death of a newborn up to one week postpartum. neonatal mortality is newborn death occurring within 28 days postpartum. neonatal death is often attributed to inadequate access to basic medical care, during pregnancy and after delivery. this accounts for 40–60% of infant mortality in developing countries. postneonatal mortality is the death of children aged 29 days to one year. the major contributors to postneonatal death are malnutrition, infectious disease, troubled pregnancy, sudden infant death syndrome, and problems with the home environment. causes causes of infant mortality directly lead to the death. environmental and social barriers prevent access to basic medical resources and thus contribute to an increasing infant mortality rate; 99% of infant deaths occur in developing countries, and 86% of these deaths are due to infections, premature births, complications during delivery, and perinatal asphyxia and birth injuries. greatest percentage reduction of infant mortality occurs in countries that already have low rates of infant mortality. common causes are preventable with low-cost measures. in the united states, a primary determinant of infant mortality risk is infant birth weight with lower birth weights increasing the risk of infant mortality. the determinants of low birth weight include socioeconomic, psychological, behavioral and environmental factors. main causes there are three main leading causes of infant mortality: premature birth-related conditions, congenital anomalies and sudden infant death syndrome. in north carolina between 1980 and 1984, premature birth-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 a premature baby in a ventilator premature, or preterm birth (ptb) is defined as birth before 37 weeks of gestation and can be further sub-classified as extreme preterm birth (occurring at less than 28 weeks gestation), very early preterm birth (occurring between 28 and 32 weeks gestation), and early to late preterm birth (between 32 and 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 period from 1980 to 2000 saw a decrease in the total number of infant mortality cases, despite a significant increase in premature births. based on distinct clinical presentation, there are three main 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 factors are viewed to be a result of similar causes, hence two main classifications remain: spontaneous and medically induced causes. the risk of spontaneous ptb increases with "extremes of maternal age (both young and old), short inter-pregnancy interval, multiple gestation, assisted reproductive technology, prior ptb, family history, substance abuse, cigarette use, low maternal socioeconomic status, late or no prenatal care, low maternal prepregnancy weight, bacterial vaginosis, periodontal disease, and poor pregnancy weight gain." medically induced ptb is often conducted when continued pregnancy poses significant risks to the pregnant parent 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. infant mortality caused by premature birth is mainly attributed to developmental immaturity, which impacts multiple organ systems of the infant's body. the 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 dysplasia (chronic lung disease), and apnea. other body systems that rely on later gestational age to fully develop include the gastrointestinal system, the skin, the immune system, the cardiovascular system, and the hematologic system. poor development of these systems increases the risk of infant mortality. 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. approximately "80% of preterm births that occur at <1,000 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 fibronectin are accurate predictors of premature birth at over 24 weeks gestation, but have a poor predictive values before then. additionally, understanding the risks associated with different gestational ages is a helpful determiner of gestational age-specific mortality. this way, the rate of infant mortality in preterm births of gestational age above 26-31weeks are significantly lower compared to those under the same age. sudden infant death syndrome (sids) main article: sudden infant death syndrome sudden infant death syndrome (sids) is defined as the sudden death of an infant less than one year of age with no cause detected after a thorough investigation. sids is more common in western countries. the united states centers for disease control and prevention reports sids to be the leading cause of death in infants age one month to one year of life. even though researchers are not sure what causes this disease, they have discovered that it is healthier for babies to sleep on their backs instead of their stomachs. this discovery saved many families from the tragedy that this disease causes. though the exact cause is unknown, the "triple-risk model" presents three factors that together may contribute to sids: the pregnant parent smoking while pregnant, the age of the infant, and stress referring to conditions such as overheating, prone sleeping, co-sleeping, and head covering. in the early 1990s, it was argued immunizations could attribute to an increased risk of sids, however later studies instead support the idea that vaccinations reduce the risk of sids. in the united states, approximately 3,500 infants deaths are sleep-related deaths, a category that includes sids. to reduce sleep-related infant deaths, the american academy of pediatrics recommends providing infants with safe-sleeping environments, breastfeeding, and immunizing according to the recommended immunization schedule. they recommend against the use of a pacifier and recommend avoiding exposure to smoke, alcohol, and illicit drugs during infancy as well as during pregnancy. congenital malformations congenital malformations are present at birth and include conditions such as cleft lip and palate, down syndrome, and heart defects. some congenital malformations may be more likely when the mother consumes alcohol, but they can also be caused by genetics or unknown factors. congenital malformations have had a significant impact on infant mortality. malnutrition and infectious diseases are the main cause of death in more undeveloped countries. for example: in the caribbean and latin america, congenital malformations only accounted for 5% of infant deaths, while malnutrition and infectious diseases accounted for 7% to 27% of infants deaths in the 1980s. in more developed countries such as the united states, there was a rise in infant deaths due to congenital malformations. these birth defects were mostly due to heart and central nervous system problems. in the 19th century, there was a decrease in the number of infant deaths from heart diseases. from 1979 to 1997, there was a 39% decline in infant mortality due to heart problems. medicine and biology causes of infant mortality and deaths that are related to medical conditions include: low birth weight, sudden infant death syndrome, malnutrition, congenital malformations and infectious diseases, and low income for health care including neglected tropical diseases. the american academy of pediatrics recommends that infants need multiple doses of vaccines such as diphtheria–tetanus–acellular pertussis vaccine, haemophilus influenzae type b (hib) vaccine, hepatitis b (hepb) vaccine, inactivated polio vaccine (ipv), and pneumococcal vaccine (pcv). research conducted by the institute of medicine's immunization safety review committee concluded that there is no relationship between these vaccines and the risk of sids in infants. low birth weight main article: low birth weight low birth weight makes up 60–80% of the infant mortality rate in developing countries. the new england journal of medicine stated that "the lowest mortality rates occur among infants weighing 3,000 to 3,500 g (6.6 to 7.7 lb). for infants born weighing 2,500 g (5.5 lb) or less, the mortality rate rapidly increases with decreasing weight, and most of the infants weighing 1,000 g (2.2 lb) or less die. as compared with normal-birth-weight infants, those with low weight at birth are almost 40 times more likely to die in the neonatal period;