Large for gestational age (LGA) means a baby is bigger than other babies of the same age. It can refer to newborns (also known as macrosomia) or babies that are still in the wombs. If you are an expectant mom or new mom, you must really want to know how to determine if your baby is large for its gestational age or not. Now let's get a closer look.

What Does Large for Gestational Age Mean?

Gestational age is an indicator for the growth and development of a fetus or infant. A fetus or newborn that is more developed or bigger in size than expected for the baby's gestational age is referred to as large for gestational age. If an unborn baby is called LGA, it means its size is larger than 90% babies of the same gestational age. A newborn with a birth weight above the 90th percentile also falls into this category.

If you want to know whether your baby is developing in the right track, you should estimate his/her gestation age and take measurements, like head size, weight and height; then you need to compare these measurements with that of an average kid of the same age and gender. LGA babies may be more vulnerable to birth injuries and at higher risks of complications like low blood sugar levels after delivery.

What Causes Baby Large for Gestational Age?

There are various factors that can make your baby large for its gestational age, which include:

1. Poorly Controlled Diabetes

Poorly controlled diabetes, particularly gestational diabetes and preexisting diabetes, is the main cause of LGA. And preexisting type 2 diabetes is more likely to be linked with macrosomia. High maternal blood sugar levels along with insulin stimulate fetal growth. Usually an increase in weight is the only symptom that LGA newborns with a history of maternal diabetes have, but if the newborn has complications, its measurements will be bigger than 90th percentile.

2. Genetics

Genetics also has an important role as heavier and taller mothers tend to have LGA babies and babies with obese moms are more likely to be LGA.

3. Other Causes

There are few other factors that may lead to LGA babies, which include:

  • Pregnancies beyond 40 weeks have higher chances of having LGA babies
  • Weight of male infants is usually heavier than that of their female counterparts
  • Multiparity
  • Congenital anomalies
  • Antibiotic during pregnancy, like Pivampicillin, amoxicillin
  • Excessive weight gain in pregnancy
  • Genetic disorders, such as Sotos syndrome and Beckwith wiedemann syndrome

What Complication Can Large for Gestational Age Bring?

A number of complications can occur as a result of large for gestational age. A few common ones are:

1. Polycythemia in Newborn

Red cell production may be high in LGA newborns, thus giving them a red appearance. Jaundice can occur due to poor feeding and high bilirubin concentration as a result of breakdown of these excessive red cells.

2. Hypoglycemia

In diabetic mothers, as the umbilical cord is cut, there is a sudden halt in the excessive supply of glucose from placenta to the baby, while the baby' pancreas continues to supply insulin. In this case, glucose levels fall in the blood and hypoglycemia occurs. Usually, newborns show no symptoms, but they can be jittery, limp and listless. They may also have eating problems for a few days right after birth.

3. Lung Issues

Newborns born to diabetic mothers are at risk of poor lung development, especially if they are born by cesarean section. Immature lungs are more likely to develop in premature babies, resulting in respiratory distress syndrome.

4. Birth Injuries

Risk of birth injuries, like brachial plexus injury or collar bone fracture, is higher in large for gestational age newborns. A large fetal head may have difficulty in passing through the mother's pelvis during vaginal delivery, especially breech delivery. In this case, caesarean delivery is recommended.

How to Deal With Large for Gestational Age

Dealing with large for gestational age can be tricky. Here are some great tips that will help you figure out what to do.

1. Before Delivery

  • Avoiding gaining too much weight and controlling blood sugar levels are the main goals if you have diabetes. You may take medicines to lower the blood sugar levels. But ask your doctor before taking any medications or prenatal vitamins.
  • A regular checkup of the baby's size and heart beat is necessary. If the baby appears to be large, you doctor will recommend labor induction or cesarean section.
  • A balanced diet including plenty of vegetables, fruits and whole grains is an important part of prenatal care.
  • Fluctuations in blood sugar levels can be controlled by eating small and frequent meals.
  • Beverages containing high amount of sugar should be avoided.
  • Proper exercises like simple daily walking are helpful.

2. After Delivery

  • Your baby should take a blood sugar test after birth to check for any decrease in blood sugar levels. This test may have to be done for several times.
  • Early and frequent feeding is required in case babies' sugar levels are low.
  • Most babies do not have serious problems due to their big size and will be sent home with general instructions on newborn care.

Other Things About Baby Being Large for Gestational Age

Here are some other things that you should know about large for gestational age:

1. Diagnosis May Be Not Accurate

As an accurate measurement of the size and weight of a fetus is not possible, hence, the accurate diagnosis of LGA can only be made after birth. An ultrasound can be used to detect large for gestational age fetus, but its inaccuracy rate is only about 50%.

2. Induction Due to Large Baby May Cause More Harm

As for complications, the prediction of a large baby may be more harmful than having a large baby itself. That's because this diagnosis is very likely wrong. What's more, if expectant moms believe they are carrying large babies, they probably turn to induction or C-section. This may cause bleeding, fever, wound infection or separation, etc.

3. Prevention of Large for Gestational Age

Regular antenatal checkup plays a vital role in pregnancy. It helps in determining the baby's size and can further lead to undetected conditions like diabetes. You can control your diabetes by following recommended care and keeping an eye on the weight.