Small baby for gestational age

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Small for gestational age is a term used to describe babies who are smaller in number for the number of weeks of pregnancy. These babies have a birth weight of less than the 10th percentile. This means that they are smaller than many other babies of the same gestational age. Many babies normally weigh more than 2.5 kg by the 37th week of pregnancy. Babies born weighing less than 2,5 kg are considered to be of low birth weight.

In this article

  • Small baby by gestational age: what to do
  • What are the baby's symptoms
  • The possible complications


Read also: Weight in pregnancy

Small baby by gestational age: what to do

Some children are small because their parents are small. But most babies of small gestational age have growth problems that occur during pregnancy. Many of these babies have a condition called intrauterine growth restriction (IUGR). This happens when the unborn baby does not receive the nutrients and oxygen needed to grow and develop organs and tissues. This can start at any time during pregnancy.

Growth restriction in early pregnancy (early onset) occurs due to chromosomal problems in the baby. It also happens due to an illness in the mother or severe placental problems. Growth restriction is called late onset if it occurs after the 32nd week of pregnancy. It is often linked to other problems.

Who is likely to be small for gestational age?

When the unborn baby does not get enough oxygen or nutrients during pregnancy, the baby's body and organs do not grow as much as they should. Some of the problems that cause babies to be small for gestational age limit the amount of blood that flows through the placenta. This can cause the baby to receive less oxygen than normal. This increases the baby's risks during pregnancy, childbirth and thereafter. Listed below are the things that can cause babies to be small for gestational age.

Problems for the mother

  • High blood pressure
  • Chronic kidney disease
  • Diabetes
  • Heart disease or respiratory disease
  • Malnutrition or anemia
  • Infection
  • Consumption of alcohol or drugs
  • Smoking cigarettes
  • With a weight of less than 45 kg

Problems with the uterus and placenta

  • Decreased blood flow in the uterus and placenta
  • The placenta detaches from the uterus
  • The placenta attaches itself low in the uterus
  • Infection in the tissues around the baby

Problems with the developing baby

  • Multiple pregnancies, such as twins or triplets
  • Infection
  • Birth defects
  • chromosomal problems

What are the baby's symptoms

Babies small for gestational age may appear mature, but they are smaller than other babies of the same gestational age. They can be small all over. Or they may be of normal length and size, but have a lower weight and body mass. These babies can be born:

  • Early. Before 37 weeks of pregnancy.
  • Full time. Between 37 and 38 weeks (first term) up to 41 weeks.
  • Post-term. After 42 weeks of pregnancy.

Many small-for-gestational-age babies have low birth weight. But not all of them are premature. They may not have the same problems as premature babies. Other babies, especially those with intrauterine growth restriction, may appear thin and pale and have loose, dry skin. The umbilical cord is often thin and dull rather than shiny and fat.

How are young babies diagnosed for gestational age?

Babies with this problem are often diagnosed with IUGR before birth. During pregnancy, a baby's size can be guessed in several ways. The height of a mother's upper uterus can be measured from the pubic bone. This measurement in centimeters often relates to the number of weeks of pregnancy after the twentieth week. If the measurement is low for the number of weeks, the baby may be smaller than expected.

Other tests used for diagnosis can include:

  • Ultrasound to estimate the size of the baby
  • Doppler flow to help control blood flow to the baby during pregnancy
  • The weight gain of the mother to tell how a baby is growing during pregnancy
  • The birth weight of the baby versus the gestational age once the baby is born. The health care professional can use a formula to calculate the baby's body mass.

How are young babies treated for gestational age?

Treatment will depend on your child's symptoms, age, and overall health. It will also depend on the severity of the condition. Children with this problem may be physically more mature than their small size would suggest. But they may be weak and less able to take large feeds or stay warm. Treatment can include:

  • Temperature-controlled beds or incubators
  • Drip feeding if the baby does not have strong sucking
  • Blood tests to check for low blood sugar
  • Watch the oxygen levels

Premature babies may also have other needs. They may need oxygen and a respirator (ventilator).

The possible complications

Babies small for gestational age or who have IUGR may have problems at birth. These can include:

  • Lower than normal oxygen levels
  • Low scores from Apgar
  • Breathing of the first stool (meconium) passed into the uterus. This can cause breathing problems.
  • Low blood sugar level
  • Difficulty maintaining a normal body temperature
  • Too many red blood cells

Can small size for gestational age be prevented?

Antenatal care is important in all pregnancies. It is especially helpful to see any problems with the child's growth. For a healthy pregnancy, stop smoking if you smoke and do not use drugs or alcohol during pregnancy. Eating a healthy diet during pregnancy can also help.

Article sources:,, hospitalbambinogesu, 

  • gestational age
  • preterm birth
  • fetal growth
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