Placental Synthesis Overview

The placenta synthesizes various hormones and proteins crucial for maintaining pregnancy and supporting fetal development. Understanding which substances are produced by the placenta is key to answering this question.

Substances Synthesized by the Placenta

• Oestriol: A major estrogen in pregnancy, synthesized by the placenta using precursors from the fetal adrenal gland and liver.
• Corticotrophin Releasing Hormone (CRH): The placenta produces significant amounts of CRH, particularly in the third trimester, which plays a role in the timing of labor.
• PAPP-A (Pregnancy Associated Plasma Protein A): This protein is synthesized by the placental trophoblast cells and is used as a biomarker in prenatal screening tests.

Substance NOT Synthesized by the Placenta

Dehydroepiandrosterone (DHEA) is primarily synthesized by the fetal and maternal adrenal glands, not the placenta. While the placenta utilizes precursors related to DHEA for hormone production (like estrogen synthesis), it does not synthesize DHEA itself.

Therefore, Dehydroepiandrosterone is the substance EXCEPT those synthesized by the placenta among the given options.