What findings are expected in Down's quadruple screen for a fetus with Down syndrome?

In a Down syndrome pregnancy, the quadruple screen, which measures levels of various substances in the mother's blood, typically shows specific abnormalities. One of the hallmark findings is elevated levels of human chorionic gonadotropin (hCG) and inhibin A. These two markers tend to be higher in the presence of Down syndrome due to the placental physiology associated with this chromosomal abnormality.

The elevated hCG and inhibin A are indicative of the altered metabolic profile in the placenta and fetal development when Down syndrome occurs. In contrast, the levels of alpha-fetoprotein (AFP) and estriol tend to be lower in pregnancies affected by Down syndrome. These findings help in assessing the risk of trisomy 21.

Therefore, the correct answer reflects the combination of high hCG and high inhibin A, which highlight the characteristic markers associated with Down syndrome on the quadruple screen. Other options do not align with these expected abnormalities, either reflecting normal findings or incorrect changes in the markers.