What happens when the baby falls below the 10% percentile?
What's the cause of fetal growth restriction? How can you prevent it? In this episode of True Birth, we will talk about fetal growth restriction/FGR previously termed IUGR or Inner Uterine Growth Restriction.
What is FGR?
It is when the baby falls below the 10th percentile for weight. 10% of babies will be below the 10th percentile, by definition. Hence, 10% of babies will be classified as fetal growth restricted. It's important for you to know that because 10% of babies are not in a pathological situation. They're not in a bad situation. They're not in a situation where they're not growing.
It's important to consider each woman and her partner uniquely in pregnancy. A women that is 5'9 with women and a woman that is 5 feet tall will have different size expectations and patterns when it comes to pregnancy.
Possible reasons that the baby is small
The number one reason that a baby could be on the smaller side is that the mother is small and the father of the baby is maybe not the tallest guy. We use the term FGR/Fetal Growth Restriction when they're in utero, but once they're delivered, we call them SGA/Small for Gestational Age.
When you find the baby's not growing well, this will generally be after 20 weeks Babies are generally the same size until 20 weeks.
Another reason the baby is small is that it's supposed to be small and there's nothing wrong. The number two reason is placental perfusion. It has a problem with the baby getting enough blood flow and nutrients. It is just not getting enough of what it needs to grow well. And there are many reasons why the placenta won't function. So when you see a small baby, especially in the third trimester after 27 weeks, 30 weeks, start thinking, "Oh, how are her blood pressures? She's spilling protein. Is there something going on with this patient that's pointing me towards preeclampsia?"
TORCH is an acronym that stands for toxoplasmosis, rubella cytomegalovirus, herpes simplex, and HIV. Cytomegalovirus is a virus that's very common in the population. Most people have been exposed to cytomegalovirus. T
To understand Dopplers without getting into the physics of what the Doppler effect is, you can take your transducer, you could put it over the cord, and you can turn on the Doppler and you could see the blood flow through the cord.
When you look at a Doppler, and you see the blood flowing the way it should, before the next heartbeat, you measure how fast it's going right before the next heartbeat.
When you talk about fetal growth restriction, you can't just talk about the baby's size because there's only one piece of it. The other piece is what is the placenta telling you? What are the Dopplers telling you?
Biometry is when you measure the femur and the abdomen and measure the head to get the size and weight of the baby and estimated fetal weight.
Guidelines about how to approach Fetal Growth Restriction
If you're below the third percentile, even if everything else is okay, that's the baby you got to deliver at 37 weeks. You can't just sit around and look at that baby for 37 weeks get the baby out. If your baby is above the third percentile and the Dopplers are elevated but not absent, get the baby up. And if there's no flow, the blood stops, that's even more concerning. If you see the reverse flow, you're dealing with a much more ominous situation and you don't want to go past 32 weeks. If you don't think the baby's doing well, you might have to come out even earlier.
One of the things that some patients might have to consider in other practices is that they would need to start having biophysical profiles done. A biophysical profile is when you're checking for a series of four different things and looking to ensure that the baby is reassuring overall. What is the baby's movement? What is fetal breathing, which is an exercise the baby does to inhale and exhale fluid? What is his tone? Is the baby flex or the floppy? Or if you feel the baby's not moving, these are things that you have to consider.
One of the things you're looking for when talking about growth restriction is you want to see how the baby is handling the uterine environment? How's the baby doing on the inside? These tests will wish to you to identify a baby that's not doing well or not getting enough blood flow. You need to know if you can wait on it and let the baby stay inside, or is it time to get the baby out? Because then the baby will do better outside of the womb.
The recommendation is that if you recognize growth restriction, you should at least be monitoring weekly, that might be nonstress tests, or that might be a biophysical every week. And if you have a severe growth that restricts a baby under the third percentile or abnormal Dopplers or accident, then twice a week. If you have reversed outside flow, put those patients in the hospital because they need to be monitored around the clock and you got to pull the baby out before it's too late.
The most reliable and consistent way to assess blood flow to the baby is the umbilical artery. Look at the ductus phimosis. When the umbilical cord hits the baby's belly button, a big part of the vein goes up into the heart carrying the birth at heart, and you can see if there's resistance, or even at the umbilical vein.
Here is the photo that we have permission to share.
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