This article has been fact checked by a Board Certified Pediatrician. Sources of information for the article are listed at the bottom.
For any content issues please Contact Us.
Intrauterine growth restriction, or IUGR, simply means that a baby is not growing well in the womb. It is often defined as a fetal weight lower than the tenth percentile for a particular gestational age. IUGR is also sometimes referred to as small for gestational age, or SGA, or fetal growth restriction.
There are many possible causes for this happening, and different risk factors as well, those factors that increase the risk that a child will not develop well.
The consequences of IUGR are also varied, and cerebral palsy is a possible complication. IUGR is considered a risk factor for cerebral palsy. Not every baby who is small for its gestational age will develop cerebral palsy, but it does increase the risk.
Understanding how and why IUGR occurs helps mothers and doctors prevent it and reduce the risk of cerebral palsy.
What is IUGR?
IUGR occurs when a fetus does not develop and grow as it should. Doctors can use ultrasound images to determine the size and approximate weight of a fetus and determine if it is growing appropriately or if it has IUGR.  If the weight of a baby is lower than the tenth percentile for its gestational age, the baby is considered not to be growing as it should.
There are two basic types of IUGR. Primary, or symmetric, IUGR occurs when all the organs in the developing fetus are too small. In asymmetric, or secondary, IUGR the head and brain development to normal size, but the abdomen is too small. This is more common than symmetric IUGR. Symmetric IUGR is more commonly associated with adverse neurological outcomes.
Causes and Risk Factors
Why IUGR happens is not always known. A baby may be growing poorly, but doctors may not be able to pinpoint the exact reason. There are many potential causes as well as risk factors that make it more likely a baby will struggle to grow and develop.
Risk factors that may contribute to the poor growth of a fetus include smoking, drug use, or alcohol abuse by the mother. Other health problems in the mother that may contribute to IUGR include heart disease, high blood pressure, gestational diabetes, rubella, kidney disease, and cytomegalovirus. 
A documented cause of IUGR is when the fetus does not get adequate nutrition or oxygen from the placenta. This may be from maternal health conditions such as diabetes, poor weight gain, or drug/ alcohol use.
It can also occur as a result of the mother having low oxygen levels as a result of being at a high altitude or having a low blood count (anemia). It can be caused by a multiple pregnancy, placental complications, or preeclampsia. Infections in the mother may also cause IUGR, especially rubella, syphilis, toxoplasmosis, and cytomegalovirus.
There may also be chromosome abnormalities or birth defects that cause a baby to fail to develop normally in the womb.
If a doctor determines that a baby is not developing or growing enough, how it is treated depends on the gestational age and the cause. If low oxygen levels are present the doctor will try to treat.
If there are placental factors present a mother may need to increase her fluid and nutrients intake. According to the National Institutes of Health (NIH), “injection of nutrients to the fetuses through intravascular port-system improved placental perfusion and metabolism.” 
A fetus that is 34 weeks or more along may be a good candidate for early delivery.
The mother can be induced to start labor or a Cesarean section may be performed. If the fetus is less than 34 weeks, the doctor is most likely to continue to monitor the situation and decide at 34 weeks if early delivery is necessary.
Complications of IUGR
IUGR must be taken seriously because a fetus that is not growing normally could end up with serious health complications. IUGR can even lead to the baby’s death either in the womb or shortly after birth.
Babies that are IUGR are at a greater risk of having low blood sugar at the time of birth, at having a lower resistance to infections, of being able to maintain adequate body temperature, of being able to cope with the stress of vaginal delivery, and of having a high red blood cell count.
IUGR and Cerebral Palsy
IUGR, compared to appropriate for gestational babies, may lead to a small head size which is associated with a 5 – 10 times risk of neurological complications. Another very important potential complication of IUGR is a lack of oxygen to the baby as it is being born.
This, in turn, can cause brain damage and cerebral palsy. Not all babies born with a small size will experience brain damage and develop cerebral palsy, but it is an increased possible risk.
Backing up the evidence that IUGR can put a baby at risk for cerebral palsy is the opposite statistic: babies a little bit larger than average for their gestational age are less likely to have cerebral palsy.
Research also suggests that the lower the baby’s weight or size due to IUGR, the greater the risk of developing cerebral palsy that is more severe. Male babies also seem to be at a greater risk of having cerebral palsy as a result of IUGR. In some cases, there is a question of whether slow growth causes brain damage and cerebral palsy or whether some brain damage has occurred that results in IUGR.
Preventing IUGR and Cerebral Palsy
It is important to understand the risk factors and causes of IUGR to take appropriate steps to try to prevent it and to in turn prevent cerebral palsy. Even with preventative measures, a fetus may not develop normally, but the more risk factors can be eliminated, the better.
This means a mother should maintain her own health as much as possible, avoiding drugs, cigarettes, and alcohol, getting good nutrition and seeing her doctor regularly to be screened and treated for the health problems that may contribute to IUGR, like preeclampsia. 
It is also crucial to monitor the fetus during pregnancy. If the doctor can pinpoint a problem in growth before it proceeds to rapidly, steps may be taken that reverse the risks and help the fetus grow and develop.
Negligence may be involved in cases in which a doctor fails to monitor the developing fetus and does not notice that it is not growing normally.
There are instances in which a fetus does not develop normally and it is no one’s fault. The mother and her medical team may have done everything right, and yet the baby does not grow normally. On the other hand, enough is known about IUGR and its risk factors and causes and how to monitor for it that doctors should be able to screen a mother for the normal growth of her fetus.
If you believe your baby did not develop normally, was too small for its gestational age, and that your child now has cerebral palsy because your doctor did not make the right choices during your pregnancy and labor, you may have a case for medical malpractice.
- Intrauterine growth restriction: MedlinePlus Medical Encyclopedia. (n.d.). MedlinePlus - Health Information from the National Library of Medicine.
Retrieved from: https://medlineplus.gov/ency/article/001500.htm
- Kilby, M., & Hodgett, S. (2000). Perinatal Viral Infections as a Cause of Intrauterine Growth Restriction. Intrauterine Growth Restriction, 29-49.
Retrieved from: https://doi.org/10.1007/978-1-4471-0735-4_3
- New Approaches to Treatment of Severe Intrauterine Growth Restriction. (n.d.). PubMed Central (PMC) National Institutes of Health
Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5960934/
- Risk of cerebral palsy in term‐born singletons according to growth status at birth. (2013, October 5). Wiley Online Library.
Retrieved from: https://onlinelibrary.wiley.com/doi/full/10.1111/dmcn.12293