By ＼ Yi-Ning Su, Wan-Ping Lee, Peng-Yu Wu
How does ultrasound measure the size of a fetus? Physicians usually look at the fetal head diameter, abdominal circumference, and thigh bone length to determine weight and whether the development is normal at this stage.
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Making labor easier with ultrasound: A common Q& A
Ultrasound is one of the most familiar tests that moms get at every checkup. The most important thing to remember is that it's not just about the way you look at it, it's about the way you look at it, and it's about the way you look at it. The first thing you need to do is to get your hands dirty.
Q. How does the ultrasound estimate the due date?
Before 12 weeks of gestation, we use ultrasound to measure the fetal head-buttock circumference, which is the length from the top of the baby's head to the ***.
At this point, fetal development is very regular, so we can use this head and hip circumference to correct for fetal growth in order to estimate the correct due date, which is more accurate than simply using the last biological period to estimate.
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Q. Can I be assured that my pregnancy will be fine if I get an ultrasound within 5 months of pregnancy?
Basically, the fetus is a growing entity, so it is absolutely impossible to say at one stage that there will not be any problems.
However, as a rule of thumb, around 20 weeks of gestation, when the fetal organ structure is more or less complete, the risk is naturally significantly reduced if nothing is detected by ultrasound at this point, but it is important to emphasize that ongoing follow-up with standard obstetrics tests is still very important!
Q. Do I have to do an ultrasound every time I go to the hospital?
This is a matter of opinion. In theory, an ultrasound can detect the most problems, but many hospitals have budgetary constraints that prevent them from providing ultrasound services at every clinic, so there are practical and cost considerations.
As the old saying goes, if you don't have a problem, you don't have to do anything, and if you do have a problem, the sooner you find out, the better, so it's up to you, the mom, to decide!
Q. Can ultrasound detect signs of preterm labor?
Yes, it can. Currently, we can use ultrasound to measure the length of the cervix. As long as the cervix is at least 2.5 centimeters long, or there is no soft opening of the uterus, the risk of preterm labor is greatly reduced.
Q. What is the approximate week of pregnancy when an ultrasound can tell the sex of the baby?
By general standards, the accuracy of ultrasound in determining the sex of the baby is close to 100% after about 16 weeks of pregnancy, but if the baby's position is not cooperative enough, the determination may be delayed.
On the other hand, since high-resolution ultrasound is becoming more and more common, by about 12 weeks of gestation, the rate of identifying the sex of the baby can be as high as 90-95 percent. However, I must emphasize that this is only possible if many of the conditions are met, and there will be individual differences.
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Q. Can ultrasound diagnose Down's syndrome?
We can use ultrasound to detect Down syndrome by using some of the soft indicators, including the nuchal translucency, nasal bone, venous catheter resistance, and tricuspid valve regurgitation, etc. Of course, it is best to use some of the special biochemistry tests, as they can reach a detection rate of about 90%.
We can use ultrasound to detect Down syndrome by using some of the soft indicators.
Q. Can ultrasound detect heart disease?
With state-of-the-art high-level ultrasound technology, 80-85% of fetal congenital heart disease can be detected, but of course, it's impossible to reach 100%, after all, there is still a scientific limit.
As for what can be done when it is detected, this is another level. With today's advances in corrective cardiac surgery, the success rate is increasing, and many fetal congenital heart defects can be detected at an early stage.
With advance notice, the pediatric cardiology team can take over at the time of birth and get the best possible outcome, much better than in the past when parents and the medical team were forced to deal with the problem without knowing anything about it and were caught unawares.