Feto-maternal haemorrhage is detected by
**Core Concept**
Feto-maternal haemorrhage refers to the transfer of fetal red blood cells into the maternal circulation, which can occur due to placental abruption, placenta previa, or other complications during pregnancy. Detecting feto-maternal haemorrhage is crucial for assessing fetal well-being and guiding further management.
**Why the Correct Answer is Right**
Feto-maternal haemorrhage is typically detected by testing for the presence of fetal hemoglobin or fetal red blood cells in the maternal circulation. One common method is the Kleihauer-Betke test, which involves treating maternal blood with acid to differentiate between adult and fetal hemoglobin. The test detects the presence of fetal hemoglobin, indicating feto-maternal haemorrhage. This method relies on the fact that fetal hemoglobin is more resistant to acid denaturation than adult hemoglobin.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe a method for detecting feto-maternal haemorrhage.
**Option B:** This option is incorrect because it does not specify a test for detecting fetal red blood cells in the maternal circulation.
**Option C:** This option is incorrect because it does not describe a widely accepted method for detecting feto-maternal haemorrhage.
**Clinical Pearl / High-Yield Fact**
It is essential to note that feto-maternal haemorrhage can lead to the development of antibodies against fetal red blood cells, which can cause hemolytic disease of the newborn (HDN) in subsequent pregnancies. The Kleihauer-Betke test can also provide an estimate of the amount of fetal hemoglobin transferred, which is useful for assessing the risk of HDN.
**Correct Answer:** D.