intrauterine growth retardation
ABBR: IUGR
A decreased rate of fetal growth, most commonly related to inadequate placental perfusion resulting from preexisting or coexisting maternal or placental factors. The infant's birth weight is below the 10th percentile on the intrauterine growth curve for the calculated gestation period. Although about 50% of cases of IUGR cannot be linked to any particular cause, certain characteristics are associated with increased fetal jeopardy: Demographic factors: Maternal age under 16 or over 40, primiparity or grand multiparity, low socioeconomic status, low weight gain, poor nutrition, and inadequate prenatal care. Maternal medical disorders: Common pre-existing and coexisting health problems, including heart disease, chronic or pregnancy-related hypertensive disease, advanced diabetes mellitus, hemoglobinopathies, asymptomatic pyelonephritis, substance abuse, drug addiction, and smoking. Placental factors: Placenta previa, small placenta, abnormal site of cord insertion, large or multiple infarcts, or thrombosis. Fetal factors: Congenital infections such as rubella, cytomegalovirus, or toxoplasmosis, particularly when occurring during an early stage of fetal development; chromosomal abnormalities and fetal anomalies; and multiple gestation, i.e., two or more fetuses.SYN: fetal growth restriction.
Symptoms: The first prenatal sign of abnormal fetal growth usually is noted during the second trimester, when the increase in fundal height is found to be less than expected for the number of weeks of gestation. Ultrasonography enables comparisons of measurements of the fetal head circumference, biparietal diameter, abdominal circumference, and femur length and the expected norms for the estimated gestational week. IUGR newborns evidence birth weights at or below the 10th percentile on the intrauterine growth curve for an equal number of weeks' gestation.
SEE: gestational age assessment.
Types: Asymmetric. There may be a disproportional reduction in size of structures. For example, the biparietal diameter may be within normal limits for gestational age, while the abdominal circumference is less than expected. Asymmetry usually reflects episodic interference with uteroplacental circulation accompanying such events as placental infarction and preeclampsia. During the neonatal period, these infants are at high risk for asphyxia, aspiration syndrome, hypocalcemia, polycythemia, and pulmonary hemorrhage. Symmetric. A generalized proportional reduction in the size of all structures and organs, other than the brain and heart, reflects diminished cell numbers related to persistent, chronic nutritional deprivation, resulting from substance abuse, congenital anomalies, and early intrauterine infection.
SEE: cocaine baby; parabiosis.
Prognosis: Asymmetric IUGR infants usually exhibit normal weights within 3 to 6 months of birth. Symmetric IUGR infants exhibit an individual potential for growth; however, their growth usually does not equal that of their peers. Later, these children may exhibit learning disabilities associated with a lessened ability to concentrate and focus on tasks because of their hyperactivity and short attention spans, and they may become frustrated because of their poor fine motor coordination.
SEE: dysmaturity.