Small for Gestational Age – Causes, Diagnosis and Treatment

During birth, the baby is weighed immediately once he/she is popped out of the belly. If the weight of the baby when born is lower than the average weight at birth, considering gerstational age, it is termed as small for gestational age baby. In this post, we have come up with all the information regarding the causes, diagnosis and treatment for SGA babies!

What is Meant By Small for Gestational Age?

Small for gestational age baby is a medical term that is used when the baby born is of lesser weight and is smaller in size as compared to other babies who are born at the same gestational age. The birth weight of SGA babies is generally lesser, to be precise below 10th percentile for babies of the same gestational age. The babies who are born as SGA appear to be normal physically and neurologically, the only difference is they are smaller as compared to other babies. They are smaller in the sense that they may be of normal length and size but would have lower body mass and weight. Babies that weigh less than 5 pounds, 8 ounces at the time of birth are considered SGA.

Key Facts About a Small-for-Gestational-Age Child

Some of the key facts regarding small for gestational age babies include:

• SGA babies need not necessarily be born prematurely. They may be born full-term (i.e. from 37 weeks to 41 weeks), post-term (i.e. after 42 weeks) or preterm (i.e. before completing 37 weeks of pregnancy).
• When the baby appears to be smaller in weight or size than expected for the number of weeks of pregnancy then it is termed as SGA.
• Sometimes babies appear to be small due to genetics. However, most of the time, babies are born SGA due to growth-related problems during pregnancy.
• If your baby, when inside the womb, does not get enough nutrients and oxygen, then they may have growth-related problems.
• SGA is a medical condition that is often suspected before delivery.
• Prenatal care and regular doctor visit are extremely important in all pregnancies to determine if there is any growth-related problem in the developing baby.

What Causes SGA Babies?

It is a general observation that sometimes genetics may be the reason for a baby being small for gestational age. But, most of the babies born SGA are because of growth-related problems during pregnancy. This often happens when the baby is diagnosed with IUGR – Intrauterine Growth Restriction which happens when the foetus does not get adequate oxygen and nutrients during pregnancy. Essential vitamins, nutrients and oxygen is a must for proper growth and development of the baby. IUGR is a medical condition that can happen at any time during pregnancy. If IUGR is detected in the earlier weeks of pregnancy then it is due to maternal diseases, chromosomal disabilities, or other severe problems with the placenta. If the growth restriction happens after 32 weeks then it is generally due to other issues. Some of the causes for small for gestational age babies include:

Maternal Factors

Some of the maternal factors that contribute to Intrauterine Growth Restriction include:

• Heart disease or respiratory disorders.
• High blood pressure.
• Diabetes.
• Anaemia or malnutrition.
• Smoking of cigarette and alcohol consumption.
• Infection.
• Drug addiction.
• Mother weighing less than 100 pounds.

Uterus and Placenta Related Factors

Some factors related to uterus and placenta include the following:

• Inadequate blood supply to the uterus and placenta.
• Severe infection in the tissues surrounding the foetus.
• The placenta attaches itself low in the uterus also known as placenta previa.
• Placenta completely detaches itself from the uterus also termed as placenta abruption.

Factors Related to Fetus

Factors associated with the developing baby that contribute towards IUGR include:

• Birth defects.
• Chromosomal disabilities.
• Twins or triplets.
• Severe infection.

Symptoms of a Baby Small for Gestational Age

Babies that are born small for gestational age may appear normal and mature physically just like other babies of the same gestational age. However, they may have lower body mass and weight as compared to other normal babies. SGA babies may be born:

• Preterm, before completion of 37 weeks of pregnancy.
• Full term, born between 37 weeks to 41 weeks of pregnancy.
• Post-term, born after 42 weeks of pregnancy.

Most of the SGA babies weigh low at the time of birth, but they are not always premature. However, they may have the same medical issues as a premature baby. SGA babies that are infected with Intrauterine Growth Restriction may appeal pale, thin and with loose dry skin. Also, the umbilical cord of the baby looks thin and dull rather than shiny and fat as in a normal scenario.

Risks and Complications in SGA Babies

Small for gestational age along with Intrauterine Growth Restriction during the pregnancy happens majorly due to inadequate supply of oxygen and nutrients to the developing baby in the womb. This is the reason that the overall body and organs of the baby do not grow in correspondence with the gestational age. The risks and complications involved in SGA babies include:

• Reduced oxygen levels than normal.
• Lower Apgar scores. Apgar score is a medical assessment that helps the doctors to identify babies that will have difficulty adapting post-delivery).
• Low blood sugar levels post-birth.
• Too much of red blood cells also termed as polycythemia.
• Difficulty in maintaining normal body temperature.
• Aspiring or breathing of meconium passed in the womb which can lead to breathing problems. Meconium is the first stool passed in the womb.

Diagnosis of SGA Baby

SGA is often diagnosed before the birth of the child. There are various ways to determine the growing baby’s size during pregnancy. The top of the mother’s uterus is measured from the pubic bone. This measurement is in centimetres and should correspond with the number of weeks of pregnancy after the 20th week. If this measurement is low then the baby may be smaller than expected and vice versa.

The diagnosis of SGA baby can be done by:

1. Ultrasound or Foetal Scan

An ultrasound uses sound waves to generate the image of the growing baby in the womb. It is one of the most accurate ways to determine the size and growth of the developing baby in the womb. An SGA ultrasound will reveal the measurement of the head and abdomen of the baby which will be lower than the estimated foetal chart. The abdominal circumference of the foetus is a very helpful indicator of nutrition intake.

2. Assessment of the Gestational Period

Immediately after the baby is born they are weighed within the first few hours. This weight is compared with the gestational age of the baby. Small for gestational age chart is prepared to know if the baby is SGA. Doctors follow a formula to calculate corresponding body mass of the baby to the gestational age.

3. Doppler Blood Flow

A Doppler flow is also an accurate way to interpret and diagnose intrauterine growth restriction during pregnancy. Doppler flow also uses sound waves to measure the blood flow, the sound of the moving blood generates a wave-form that reflects the speed and quantity of blood as it moves through the blood vessels. Doppler flow test can be used to determine the blood flow in the foetal brain and umbilical cord attached to the baby.

4. Weight Gained By the Mother

The mother usually gains a lot of weight during pregnancy. The weight gained by the mothers can also indicate the size of the baby. Smaller mothers with less weight gain will generally have a smaller size baby.

Treatments for SGA Neonates

The treatment of SGA babies may include the following:

• Feeding through tubes, if the baby cannot be fed naturally.
• Incubator facility or temperature-controlled bed.
• Continuous monitoring of oxygen levels.
• Blood tests to check low blood sugar levels at the time of birth.

Preventing SGA Pregnancy

Prenatal care and regular doctor consultations are extremely important before, during and after pregnancy. Medical care during pregnancy helps determine foetal growth and development related problems at an early stage. This gives you a chance to treat the problems with proper medication and nutrition. Complete elimination of alcohol, drugs, and cigarettes are extremely essential for a healthy pregnancy. Prenatal care, along with a healthy diet during pregnancy prevents the risk of small for gestational age icd 10.

We hope that the above post helps you understand about SGA infants, causes, and all the risks associated with it. Prevention is always better than cure! It’s always best to consult a doctor before planning your pregnancy, the detailed counselling session will help you understand what to expect and how to care for your baby throughout the pregnancy!

Also Read: 

Does Gestational Diabetes Affect Your Delivery Options?
How Does Gestational Diabetes Affect Baby and Mother
Gestational Sac while Pregnant