Progesterone is mainly produced by what structure later in pregnancy?

Progesterone is primarily produced by the placenta during the later stages of pregnancy. After implantation, the placenta becomes the main source of hormonal support for the developing fetus and maternal adaptations. This shift in progesterone production is critical for maintaining the pregnancy, as it helps to maintain the uterine lining, reduces uterine contractions, and supports conditions favorable for fetal growth and development.

During the first trimester, the corpus luteum produces progesterone until the placenta is sufficiently developed and can take over this role. After the first trimester, the reliance on the corpus luteum diminishes significantly, and the placenta remains the predominant source of progesterone throughout the remainder of the pregnancy.

While the adrenal glands and ovaries do produce some hormones, they are not the primary producers of progesterone during later pregnancy stages. The focus on the placenta's role reflects its critical function in sustaining pregnancy and the health of both the mother and the developing fetus.