Which hormone is produced by the placenta to maintain pregnancy in the later stages?

• A. Progesterone
• B. Estrogen
• C. hCG
• D. Relaxin

Answer: (A)

Progesterone is the hormone that keeps the uterus in a quiescent state and maintains the lining (decidua) of the uterus during pregnancy. In the later stages, the placenta becomes the main source of progesterone, which is crucial for preventing contractions of the uterine smooth muscle and for sustaining the decidual environment that supports the growing fetus. This hormonal support helps prevent miscarriage and allows the pregnancy to continue to term.

Estrogen also rises and supports pregnancy, but it does not by itself maintain pregnancy the way progesterone does. hCG’s early role is to rescue the corpus luteum and sustain progesterone production in the first trimester, after which the placenta largely takes over. Relaxin contributes to tissue remodeling and ligament laxity but is not the primary hormone responsible for maintaining pregnancy.