What is encompassed by the term "conceptus"?

The term "conceptus" refers to all tissue products of conception, which includes not only the developing embryo and fetus but also all associated structures that support pregnancy. This encompasses the placenta, amniotic fluid, chorion, and any other related components. Understanding "conceptus" in this way is critical, as it highlights the interconnectedness of all tissues that contribute to the developing pregnancy from fertilization through delivery.

The developing fetus is indeed a part of the conceptus, but limiting the definition to just the fetus overlooks the importance of the supportive structures. Similarly, the embryo and paternal genetic material do not give a complete representation of what the conceptus includes, as it ignores the maternal contributions and supporting tissues. Finally, focusing solely on the amniotic fluid and placenta neglects the embryo and fetus, essential aspects of the conceptus. Therefore, defining "conceptus" as all tissue products of conception provides the most accurate and comprehensive understanding of embryonic and fetal development.