Breathing movement of fetus on USG is first detected on?
**Core Concept**
The breathing movement of a fetus is a key indicator of its well-being and development. This movement is detected through ultrasound (USG) and is an essential parameter in fetal monitoring.
**Why the Correct Answer is Right**
The breathing movement of a fetus is first detected around 11-12 weeks of gestation. This is because the fetal diaphragm starts to develop and contract at this stage, resulting in the characteristic breathing movements seen on USG. The detection of breathing movements is an important milestone in fetal development and is often used as an indicator of fetal maturity.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the breathing movement of a fetus is not first detected at 8 weeks of gestation. At this stage, the fetal diaphragm is still in its early stages of development and has not yet started to contract.
**Option B:** This option is incorrect because the breathing movement of a fetus is not first detected at 15 weeks of gestation. While the fetal diaphragm is well-developed by this stage, the breathing movements are typically detected earlier, around 11-12 weeks.
**Option C:** This option is incorrect because the breathing movement of a fetus is not first detected at 18 weeks of gestation. This stage is actually much later than the optimal time for detecting breathing movements, which is typically around 11-12 weeks.
**Option D:** This option is incorrect because there is no specific gestational age mentioned. However, if we assume this option is trying to say that breathing movements are detected at a specific gestational age that is not 11-12 weeks, then this option would be incorrect because the correct answer is specifically 11-12 weeks.
**Clinical Pearl / High-Yield Fact**
The detection of breathing movements on USG is an important milestone in fetal development and is often used as an indicator of fetal maturity. It is essential for obstetricians and sonographers to accurately detect and record these movements to ensure the well-being of the fetus.
**Correct Answer:** C. 11-12 weeks.