False Negative Hydrostatic test in a live born foetus may be seen in:
**Core Concept**
The hydrostatic test, also known as the float test, is a forensic method used to determine whether a newborn infant was stillborn or had breathed after birth. The test relies on the principle that air-filled lungs will float in water, while lungs that have not expanded with air will sink.
**Why the Correct Answer is Right**
In a live-born fetus, the lungs are inflated with air due to the first breath taken after birth. However, if the fetus is submerged in water immediately after birth, the lungs may not have time to expand with air, resulting in a false negative float test. This is because the lungs are still in a state of collapse, and the water pressure prevents them from expanding. The presence of meconium in the airways can also contribute to a false negative result.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the scenario described. The presence of a placenta would not affect the outcome of the hydrostatic test.
**Option B:** This option is incorrect because it does not address the specific scenario of a live-born fetus with a false negative float test.
**Option C:** This option is not relevant to the scenario described. The presence of a umbilical cord does not affect the outcome of the hydrostatic test.
**Clinical Pearl / High-Yield Fact**
In cases where a false negative float test is suspected, a chest X-ray or other diagnostic tests may be necessary to confirm the presence of air in the lungs.
**Correct Answer: C. Meconium aspiration.**