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Intrauterine Growth Retardation

Last updated Oct. 16, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Intrauterine Growth Retardation (IUGR) is when a baby has less than the average growth in the womb during pregnancy. The condition is also referred to as Small-for Gestational Age (SGA).

What are the other names for this Condition? (Also known as/Synonyms)

  • Fetal Growth Restriction
  • Intrauterine Growth Restriction
  • Small-for Gestational Age (SGA)

What is Intrauterine Growth Retardation? (Definition/Background Information)

  • Intrauterine Growth Retardation (IUGR) is when a baby has less than the average growth in the womb during pregnancy. The condition is also referred to as Small-for Gestational Age (SGA)
  • There are 2 forms of IUGR:
    • Symmetric or Primary Intrauterine Growth Retardation: This occurs when the internal organs are smaller than average size. This form of IUGR occurs in 25% of the cases
    • Asymmetric or Secondary Intrauterine Growth Retardation: This occurs when the head and brain are sized normally, but the abdomen is smaller than normal. This type of IUGR generally cannot be diagnosed until the third trimester
  • Intrauterine Growth Retardation has many causes, including lack of oxygen in the placenta, certain infections, lack of nutrition in the expectant mother, drug and alcohol use by the mother, and multiple pregnancies
  • An ultrasound can help determine whether the fetal growth measurement is below average in order to diagnose Intrauterine Growth Retardation
  • A Cesarean section may be recommended for delivering a baby with the condition, in most cases.  The severity of Intrauterine Growth Retardation often determines the prognosis of the baby after birth and maintenance of health after birth
  • Pregnant women should have multiple prenatal check-ups with a healthcare provider to periodically assess the baby’s growth and development. This can help prevent Intrauterine Growth Retardation

Who gets Intrauterine Growth Retardation? (Age and Sex Distribution)

  • Intrauterine Growth Retardation is a condition that affects the unborn fetus and occurs due to several different factors
  • Pregnant women with poor diet, risky behavior, and other illnesses are more likely to be affected
  • No gender, racial or ethnic group predilection is observed; however, IUGR is more prevalent in the developing regions of the world (poorer economies), due to inadequate food and nutrition supply for the expectant mothers

What are the Risk Factors for Intrauterine Growth Retardation? (Predisposing Factors)

There may be multiple risk factors during a pregnancy that can result in Intrauterine Growth Retardation:

  • Weight of the pregnant woman is less than 100 lbs (about 44 Kgs): However, it is important to note that 100 lbs is a rough approximation, because there is a wide variation (of average body weight of women) across different races and ethnic groups, around the world
  • Poor diet and nutrition while pregnant
  • Use of drugs, alcohol, and smoking during pregnancy
  • Adverse health conditions affecting the placenta or umbilical cord
  • Gestational diabetes
  • Low amounts of amniotic fluid or oligohydramnios
  • Hypertension caused by pregnancy (or pregnancy-induced hypertension)
  • Pregnancy with multiple babies
  • Birth defects
  • Chromosomal abnormalities

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the causes of Intrauterine Growth Retardation? (Etiology)

There are many possible causes of Intrauterine Growth Retardation. These include:

  • During pregnancy, the developing fetus may not receive enough oxygen and nutrition from the placenta, which can be caused by multiple pregnancies, abnormalities of the placenta, eclampsia (seizures), or high altitudes
  • Congenital abnormalities at birth can cause IUGR
  • Chromosomal abnormalities can cause underweight babies
  • Infections during pregnancy such as TORCH; TORCH stands for several infectious diseases caused by toxoplasmosis, rubella, cytomegalovirus, and herpes simplex virus
  • Use of alcohol, smoking, or drugs by pregnant women
  • Blood clot formation in the expectant mother
  • High blood pressure or heart defects in the expectant mother
  • Kidney disease
  • A lack of proper nutrition resulting in vitamin (vitamin B 12 and folate) and mineral (iron) deficiencies

What are the Signs and Symptoms of Intrauterine Growth Retardation?

The signs and symptoms of Intrauterine Growth Retardation may include the following:

  • A sign of IUGR can be that the expectant mother does not feel enough growth of her child during pregnancy. This means that the mother does not feel the size of her belly to be increasing according to the stage of the pregnancy
  • IUGR can also be indicated from a smaller than average uterus size in a pregnant woman, during an ultrasound scan procedure of the abdomen
  • If IUGR is caused by an infection, then the signs and symptoms of the infection may be present
  • Otherwise, the symptoms may be difficult to determine since pregnancies differ with each other
  • Regular prenatal check-ups with a healthcare provider are mandatory to check for any fetal abnormality including Intrauterine Growth Retardation

Often, many pregnant women with Intrauterine Growth Retardation (affecting fetal development) do not experience significant signs and symptoms. Hence, the condition may go undiagnosed without a proper prenatal examination.

How is Intrauterine Growth Retardation Diagnosed?

Intrauterine Growth Retardation is generally diagnosed through the following tools in a pregnant woman:

  • Regular checkups and physical exam with a healthcare provider
  • Ultrasound scan measurement of the uterus size can help determine if the uterus size is appropriate for gestational age
  • If Intrauterine Growth Retardation is suspected, the fundal height (measurement of the uterus from the top of the uterus to the top of the pubic symphysis) is used to determine, if the uterus size is appropriate for the gestational age
  • IUGR can be generally diagnosed with a prenatal ultrasound exam to determine the baby’s size. If the fetal measurement is below the 10th percentile (on the basis of gestational age), a diagnosis of IUGR may be confirmed
  • A Doppler ultrasound can be performed and any abnormal readings may point to an IUGR

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible complications of Intrauterine Growth Retardation?

The possible complications of Intrauterine Growth Retardation may include:

  • C-section delivery may be necessary to deliver the baby because the process of delivery can cause more complications in a baby with IUGR, than a baby without the condition
  • There is an increased risk for a lack of oxygen (or hypoxia) when a baby is born. This may result in lower Apgar scores at birth
  • Meconium aspiration can occur if an infant ingests the first bowel movement, which can lead to meconium aspiration syndrome in the baby
  • Low blood sugar (hypoglycemia)
  • Blood flow can be reduced (hyperviscosity) due to increased number of red blood cells (polycythemia)
  • Infants with IUGR may develop reduced levels of motor skills or have neurological problems

Generally, complication rates in a newborn with IUGR may be higher and more severe than babies without IUGR (such as a normally healthy baby).

How is Intrauterine Growth Retardation Treated?

Intrauterine Growth Retardation is treated with the following steps:

  • Once the condition is diagnosed, the pregnant mother is closely monitored
  • The healthcare provider may recommend the frequency of prenatal appointments to monitor the progress of the baby’s growth
  • Frequent ultrasounds are used to determine parameters such as the growth of the baby, blood flow, and fluid surrounding the baby
  • The fetal heartbeat is monitored through a procedure called a non-stress test
  • If IUGR is confirmed, then often babies will need to be delivered earlier than normally expected dates; usually after the fetus reaches the gestational age of 34 weeks or more

How can Intrauterine Growth Retardation be Prevented?

Intrauterine Growth Retardation can be prevented in various ways that include:

  • Alcohol, cigarettes, and drug should be completely avoided during pregnancy
  • A healthy and nutritious diet can reduce the risk of IUGR
  • Regular prenatal checkups are necessary
  • Pregnant women should be educated on the adverse effects of any current medications or chronic medical conditions

What is the Prognosis of Intrauterine Growth Retardation? (Outcomes/Resolutions)

  • A baby’s health, growth, and development after birth is dependent on the case and severity of Intrauterine Growth Retardation
  • Often, IUGR can be monitored and a baby can be safely delivered. In such cases, the prognosis is good

Additional and Relevant Useful Information for Intrauterine Growth Retardation:

  • There are about 200,000 cases of Intrauterine Growth Retardation in the United States annually. A majority of cases are monitored and early delivery of the baby is usually undertaken
  • Anemia in pregnancy refers to low hemoglobin levels or decreased red blood cell count causing decreased oxygen-carrying capacity in a pregnant woman. This reduced oxygen-carrying capacity results in reduced oxygen supply both to the mother and to the developing baby. Anemia during pregnancy can lead to IUGR of the baby

The following article link will help you understand anemia in pregnancy:


What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: June 22, 2016
Last updated: Oct. 16, 2018