Hypothermia, thrombocytopenia, leukopenia, hypocalcemia, and bleeding in the lungs are often results of IUGR.Infants with IUGR are at increased risk of perinatal asphyxia due to chronic hypoxia, usually associated with placental insufficiency, placental abruption, or a umbilical cord accident. This chronic hypoxia also places IUGR infants at elevated risk of persistent pulmonary hypertension of the newborn, which can impair an infants blood oxygenation and transition to postnatal circulation.If the cause of IUGR is intrinsic to the fetus, growth is restricted due to genetic factors or as a sequela of infection. IUGR is associated with a wide range of short- and long-term neurodevelopmental disorders. Cardiovascular
In IUGR, there is an increase in vascular resistance in the placental circulation, causing an increase in cardiac afterload. There is also increased vasoconstriction of the arteries in the periphery, which occurs in response to chronic hypoxia in order to preserve adequate blood flow to the fetus vital organs. This prolonged vasoconstriction leads to remodeling and stiffening of the arteries, which also contributes to the increase in cardiac afterload. Therefore, the fetal heart must work harder to contract during each heartbeat, which leads to an increase in wall stress and cardiac hypertrophy. These changes in the fetal heart lead to increased long-term risk of hypertension, atherosclerosis, cardiovascular disease, and stroke. Pulmonary
Normal lung development is interrupted in fetuses with IUGR, which increases their risk for respiratory compromise and impaired lung function later in life.
Furthermore, rapid metabolic and physiologic changes in the first few days after birth can yield susceptibility to hypocalcemia, polycythemia, immunologic compromise, and renal dysfunction. Long-term consequences
According to the theory of thrifty phenotype, intrauterine growth restriction triggers epigenetic responses in the fetus that are otherwise activated in times of chronic food shortage. If the offspring actually develops in an environment where food is readily accessible, it may be more prone to metabolic disorders, such as obesity and type II diabetes.Infants with IUGR may continue to show signs of abnormal growth throughout childhood. Infants with asymmetric IUGR (head-sparing) typically have more robust catch-up postnatal growth, as compared with infants with symmetric IUGR, who may remain small throughout life. The majority of catch-up growth occurs in the first 6 months of life, but can continue throughout the first two years. Approximately 10% of infants who are small for gestational age due to IUGR will still have short stature in late childhood.Infants with IUGR are also at elevated risk for neurodevelopmental abnormalities, including motor delay and cognitive impairments. Low IQ in adulthood may occur in up to one third of infants born small for gestational age due to IUGR. Infants who fail to display adequate catch-up growth in the first few years of life may exhibit worse outcomes.Catch-up growth can alter fat distribution in children diagnosed with IUGR as infants and increase risk of metabolic syndrome. Infants with IUGR may be susceptible to long-term dysfunction of several endocrine processes, including growth hormone signaling, the hypothalamic-pituitary-adrenal axis, and puberty.