Percentile: measuring baby's growth
One of the most common ways to measure a baby's growth is through percentiles. But what does this mean in practice? A percentile is a way to compare the baby's size to other fetuses of the same gestational age. This number can range from 0 to 100, and variations are normal within certain limits.
- Babies considered to be within the normal range are those in the 10th and 90th percentiles.
- Below the 10th percentile, the baby is considered small for gestational age.
- Above the 90th percentile, it is considered large for gestational age.
Imagine a line of 10-year-old children. They are all the same age, but some are taller and others shorter. The same happens with babies in the womb. They may be smaller or larger, but still within a healthy range. However, when a baby is below the 10th percentile or above the 90th, there may be a need for further investigation.
What is normal growth?
During pregnancy, the baby's growth should follow an upward curve over time. When we talk about normal growth, we are referring to the normal growth curve, which tracks the gradual increase in the fetus's weight and measurements. This curve is similar to those used by pediatricians after birth when measuring children's weight and height at each appointment.
An important point is that, even if the baby is smaller or larger, it can be growing healthily, as long as it follows the expected growth pattern.
What is fetal growth restriction?
Fetal Growth Restriction (FGR) occurs when a baby stops growing as expected for its gestational age. The causes are varied, and the most common include:
- Infections, especially in the first trimester, such as TORCH infections (toxoplasmosis, rubella, cytomegalovirus, among others).
- Genetic diseases, such as Down syndrome.
- Placental insufficiency, which occurs when the placenta does not provide adequate nutrients and oxygen to the baby.
This last cause, placental insufficiency, is the most common and can affect up to 101% of pregnancies. FGR can have serious consequences, such as neurological sequelae and even fetal death. Furthermore, children born with fetal growth restriction have a higher risk of developing health problems in adulthood, such as cardiovascular and metabolic diseases (diabetes and hypertension).
Early growth restriction
Early Growth Restriction is the most severe form of FGR and occurs before the 32nd week of gestation. In this type of restriction, placental insufficiency is usually severe, and the mother may experience health problems such as pre-eclampsia (a severe high-pressure condition).
This situation puts both the mother and the baby at risk. In the fetus, the lack of nutrients can lead to malnutrition and hypoxia (lack of oxygen), which can culminate in severe complications, such as the need for premature delivery, as well as sequelae and even fetal death. In these situations, doctors need to make difficult decisions: wait longer in an attempt to keep the baby in the womb and gain maturity for better birth conditions, or induce labor and deal with the risks of prematurity.
Late growth restriction
Late-onset fetal growth restriction (FGR) is more common and occurs after the 32nd week of gestation, potentially affecting up to 10% of pregnancies. Although less severe than the early form, late FGR also requires attention. In this type of restriction, the changes in the baby's growth are more subtle, and umbilical artery Doppler, an important test for identifying problems in placental blood flow, is often normal.
The biggest challenge in late fetal growth restriction is diagnosis, as the changes can be more difficult to identify, requiring experience and care from the fetal medicine physician.
Possible consequences and treatments
The consequences of fetal growth restriction (FGR), both early and late, can be serious, but there are monitoring and treatment options that help minimize the risks. Regular monitoring with ultrasound and Doppler exams is essential to track the flow of nutrients and oxygen to the baby. In severe cases, it may be necessary to induce labor early.
The important thing is that, by identifying FCR early, it is possible to take steps to ensure the best possible outcome for both mother and baby.
O follow-up Understanding fetal growth is crucial to ensuring the baby develops healthily during pregnancy. Understanding percentiles, normal growth, and the different forms of fetal growth restriction is essential for expectant mothers.
If you are pregnant and have concerns about your baby's growth, talk to your doctor. They will be able to guide you and perform the necessary tests to ensure that everything is going well with your little one's development.
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