Small for Gestational Age

Small for gestational age is a term
used to describe babies who are smaller than number for the number of weeks of
pregnancy. These babies have birth weight below the 10th percentile. This means they
are
smaller than many other babies of the same gestational age. Many babies normally weigh
more than 5 pounds, 13 ounces by the 37th week of pregnancy. Babies born weighing
less
than 5 pounds, 8 ounces are considered low birth weight.

Some babies are small because their
parents are small. But most babies who are small for gestational age have growth
problems that happen during pregnancy. Many of these babies have a condition called
intrauterine growth restriction (IUGR). This happens when the unborn baby doesn’t
get
the nutrients and oxygen needed to grow and develop organs and tissues. This can begin
at any time in pregnancy.

Growth restriction early in
pregnancy (early onset) happens because of chromosome problems in the baby. It also
happens because of disease in the mother, or severe problems with the placenta. Growth
restriction is called late onset if it happens after week 32 of the pregnancy. It
is
often linked to other problems.

When the unborn baby doesn’t get enough oxygen or nutrients during pregnancy, the
baby’s body and organs don’t grow as much as they should. Some of the problems that
cause babies to be small for gestational age limit how much blood flows through the
placenta. This can cause the baby to get less oxygen than normal. This increases the
baby’s risks during pregnancy and delivery, and later. Things that can cause babies
to be small for gestational age are listed below.

Problems with the mother

  • High blood pressure
  • Chronic kidney disease
  • Diabetes
  • Heart disease or respiratory disease
  • Malnutrition or anemia
  • Infection
  • Alcohol or drug use
  • Cigarette smoking
  • Weighing less than 100 pounds

Problems with the uterus and placenta

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

Problems with the developing baby

  • Multiple pregnancy, such as twins or triplets
  • Infection
  • Birth defects
  • Chromosome problems

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

  • Premature. Before 37 weeks of pregnancy.
  • Full-term. Between 37 and 38 weeks (early term) through 41 weeks.
  • Post-term. After 42 weeks of pregnancy.

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

Babies with this problem are often
diagnosed with IUGR before birth. During pregnancy, a baby’s size can be guessed in
different ways. The height of the top of a mother’s uterus can be measured from the
pubic bone. This measurement in centimeters often links with the number of weeks of
pregnancy after the 20th week. If the measurement is low for the number of weeks,
then
the baby may be smaller than expected.

Other tests used for diagnosis may include:

  • Ultrasound to estimate the baby’s size
  • Doppler flow to help check blood flow to the baby during pregnancy
  • Mother’s weight gain to tell how a baby is growing during pregnancy
  • Baby’s birth weight as compared with the gestational age once the baby is born. The
    healthcare provider may use a formula to figure out the baby’s body mass.

Treatment will depend on your child’s symptoms, age, and general health. It will also
depend on how severe the condition is. Babies 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 feedings or stay warm. Treatment may include:

  • Temperature-controlled beds or incubators
  • Tube feedings if the baby doesn’t have
    a strong suck
  • Blood tests to check for low blood sugar
  • Watching oxygen levels

Babies who are also premature may have other needs. They may need oxygen and a breathing
machine (ventilator).

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

  • Lower oxygen levels than normal
  • Low Apgar scores
  • Breathing in the first stools (meconium) passed in the womb. This can cause breathing
    problems.
  • Low blood sugar
  • Trouble keeping a normal body
    temperature
  • Too many red blood cells

Prenatal care is important in all pregnancies. It is especially helpful to see any
problems with the baby’s growth. For a healthy pregnancy, stop smoking if you smoke,
and don’t use drugs or alcohol while you are pregnant. Eating a healthy diet during
pregnancy may also help.

  • Small for gestational age means a baby is smaller than expected for the number of
    weeks of pregnancy.
  • Some babies are small because their
    parents are small. But most babies who are small for gestational age have growth
    problems that happen during pregnancy.
  • When the unborn baby does not get
    enough oxygen or nutrients during pregnancy, they don’t grow as much as normal.
  • The condition is often suspected before birth.
  • Prenatal care is important in all pregnancies. It is especially helpful to see any
    growth problems of the developing baby.

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
    or tests. Also write down any new instructions your provider gives you for your child.
  • Know why a new medicine or treatment is prescribed and how it will help your child.
    Also know what the side effects are.
  • Ask if your child’s condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if your child does not take the medicine or have the test or procedure.
  • If your child has a follow-up appointment, write down the date, time, and purpose
    for that visit.
  • Know how you can contact your child’s provider after office hours. This is important
    if your child becomes ill and you have questions or need advice.