Introduction
Large for gestational age (LGA) is a term used in obstetrics to describe a baby who is significantly larger than the average size for their gestational age. In other words, an LGA baby is born with a birth weight that is above the 90th percentile for their gestational age. Gestational age refers to the age of the fetus or baby in terms of the number of weeks since the first day of the mother's last menstrual period. It is typically estimated through early ultrasound measurements during the first trimester. The size of a baby can be assessed using growth charts that indicate the average weight and length of babies at different gestational ages.
What Are the Causes of Large Gestational Age (LGA)?
A few conditions in a mother can lead to large gestational age, which include:
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Diabetes: Diabetes in mothers is the common cause of obesity at gestational age. Women who are affected with diabetes during pregnancy are called gestational diabetes. Women with diabetes who have increased blood glucose levels can pass the same amount of glucose levels to the baby through the placenta. In reaction to the increased blood sugar levels, the baby's body produces more insulin from the pancreas. This increased insulin results in quicker growth of the baby than usual.
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Inaccurate Gestational Age: Improperly calculated gestational age could also lead to LGA. This is usually seen in women with irregular periods, women who do not remember when their last menstrual cycle was, and women who are using birth control pills or hormonal pills. Sometimes doctors can also miscalculate the gestational age from the ultrasounds.
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Genetical Inheritance: In some cases, genetics play an important role in determining the size of the baby. Parents who have large stature can also have larger-sized babies.
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Weight Gain During Pregnancy: Every carrying mother gains weight during pregnancy. Unwanted or unhealthy weight gain could lead to large gestational-age babies. Hence pregnant mothers should always be involved in physical activities to prevent unwanted weight gain. Weight before the onset of pregnancy must be noted, and it should always be compared with weight gain during pregnancy.
What Are the Complications In Large for Gestational Age Babies?
Large-sized babies can cause the following complications:
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Extended Labor: Extended or prolonged labor can result in complications for both the mother and the baby. The baby's large size may lead to obstruction in the birth canal, causing inadequate oxygen supply to the baby.
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Strenuous Delivery: Due to the baby's enlarged head, the mother is required to exert significant effort to push the baby through the birth canal, leading to considerable stress and strain on her. This becomes even more challenging if the baby is in the breech position, making it difficult for the baby's head to fit into the birth canal. In such cases, medical intervention like forceps or a vacuum extractor may be employed by the doctor to safely deliver the baby. Consequently, in situations involving larger gestational-age babies, medical procedures such as Cesarean delivery (C-section) or episiotomy are often performed.
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Birth Injuries: Due to the increased size of the baby, birth injuries are common while passing through the birth canal. The birth injuries include a fractured collar bone and damage to the nerves around the shoulder region. Sometimes cerebral palsy can also occur because of the decreased oxygen supply to the baby.
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Meconium Aspiration: Meconium is a dark green-colored fecal material that is produced in the intestine of the fetus before delivery. Large for gestational age babies are at risk of inhalation of this meconium into the lungs.
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Polycythemia: Abnormal increase in the count of red blood cells is called polycythemia. LAG infants have a high abnormal count of red blood cells. This excess amount of red blood cells increases the viscosity of the blood. Thereby, the blood circulation is slowed down, leading to hyperbilirubinemia, where the skin, eyes, and mucous membranes of the newborn appear yellow, leading to jaundice. Babies with polycythemia appear reddish in color.
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Birth Defects: Infants born to mothers with uncontrolled diabetes face the risk of developing organ defects, affecting their heart, lungs, kidneys, brain, and spinal cord.
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Respiratory Distress Syndrome: Delayed lung development is observed in infants whose mothers have diabetes. Hence the LGA babies develop respiratory distress even though they are born at full term.
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Hypoglycemia: Newly born LGA babies have low blood glucose (sugar) levels. During pregnancy, if the mother is suffering from uncontrolled diabetes, high glucose levels in the blood of the mother are passed to the fetus via the placenta, and in response to the high glucose levels, the fetus's body produces more amount of insulin from the pancreas. After delivery, suddenly, the blood supply from the mother is cut off, and the high insulin levels in the infant's body can drop the glucose levels causing hypoglycemia in the newborns. As such, hypoglycemia does not cause any symptoms, but babies with hypoglycemia look lazy and lethargic.
How to Diagnose Large For Gestation?
Diagnosis of LGA can be done in two ways:
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Before Birth: LGA can be detected by ultrasonography and measuring the uterus.
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Ultrasonography: During regular follow-ups, pregnant women are advised for ultrasonography. This helps in the estimation of fetal size and weight which could confirm LGA.
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Measurement Of Uterus: Doctors take the measurement from the top of the abdomen from the top of the pubic bone to the top of the uterus (fundus). These measurements correspond to the pregnancy's duration, and if the measurement is greater than expected for the number of weeks, the baby is classified as LGA (large for gestational age).
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After Birth: After the birth of the baby, weight is measured, and if the weight of the newborn is around 4000-4400 grams, then the baby is assumed to be LGA.
How to Treat Large for Gestational Age?
As such, there is no treatment advised for gestational age, but managing the complications faced by newborns with being overweight is of primary importance. For example:
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Polycythemia can be treated by administering intravenous fluids. In severe instances, a partial blood exchange may be performed, where some blood is withdrawn and replaced with normal saline, effectively diluting the remaining blood volume.
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Hypoglycemia can be treated by repeated feedings from time to time.
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Respiratory distress can be managed by placing the baby on a ventilator or on CPAP (continuous positive airway pressure) until the newborns breathe on their own.
Conclusion
Prenatal check-ups are very important for all pregnant mothers. Fetal monitoring must be done at regular intervals to check for the weight of the fetus. During these routine examinations, if the baby is found to be large for the gestational age-this helps in identifying the undetected underlying conditions like diabetes and other health issues in the mother. Timely weight gain, according to the guidance of the doctor, and managing the diabetes condition can help prevent and lower the risk of large for gestational age.
