Renal dysfunction, disrupted lung development, and impaired bone metabolism are also associated with IUGR. Animals
In sheep, intrauterine growth restriction can be caused by heat stress in early to mid pregnancy. The effect is attributed to reduced placental development causing reduced fetal growth. Hormonal effects appear implicated in the reduced placental development. Although early reduction of placental development is not accompanied by concurrent reduction of fetal growth; it tends to limit fetal growth later in gestation. Normally, ovine placental mass increases until about day 70 of gestation,  but high demand on the placenta for fetal growth occurs later. (For example, research results suggest that a normal average singleton Suffolk x Targhee sheep fetus has a mass of about 0.15 kg at day 70, and growth rates of about 31 g/day at day 80, 129 g/day at day 120 and 199 g/day at day 140 of gestation, reaching a mass of about 6.21 kg at day 140, a few days before parturition.) In adolescent ewes (i.e. ewe hoggets), overfeeding during pregnancy can also cause intrauterine growth restriction, by altering nutrient partitioning between dam and conceptus. Fetal growth restriction in adolescent ewes overnourished during early to mid pregnancy is not avoided by switching to lower nutrient intake after day 90 of gestation; whereas such switching at day 50 does result in greater placental growth and enhanced pregnancy outcome. Practical implications include the importance of estimating a threshold for "overnutrition" in management of pregnant ewe hoggets.
However, the timing of  delivery is currently based on the cause of IUGR and parameters collected from the umbilical artery doppler. Some of these include: pulsatility index, resistance index, and end-diastolic velocities, which are measurements of the fetal circulation. Fetuses with an anticipated delivery before 34 weeks gestation are recommended to receive corticosteroids to facilitate fetal maturation. Anticipated births before 32 weeks should receive magnesium sulfate to protect development of the fetal brain. Outcomes
Postnatal complications
After correcting for several factors such as low gestational parental weight, it is estimated that only around 3% of pregnancies are affected by true IUGR. 20% of stillborn infants exhibit IUGR. Perinatal mortality rates are 4-8 times higher for infants with IUGR, and morbidity is present in 50% of surviving infants. Common causes of mortality in fetuses/infants with IUGR include: severe placental insufficiency and chronic hypoxia, congenital malformations, congenital infections, placental abruption, cord accidents, cord prolapse, placental infarcts, and severe perinatal depression.IUGR is more common in preterm infants than in full term (37–40 weeks gestation) infants, and its frequency decreases with increasing gestational age. Relative to premature infants who do not exhibit IUGR, premature infants with IUGR are more likely to have adverse neonatal outcomes, including respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis. This association with prematurity suggests utility of screening for IUGR as a potential risk factor for preterm labor.Feeding intolerance, hypothermia, hypoglycemia, and hyperglycemia are all common in infants in the postnatal period, indicating the need to closely manage these patients temperature and nutrition.