Progesterone is made during the third trimester by the:

placenta

endometrial lining

chorion

corpus luteum

placenta

Explanation:

In the first trimester of pregnancy, the placenta is still in formation and what maintains the metabolism of pregnancy is progesterone, produced by the ovary in high doses. After these three months, the placenta takes over, that is, progesterone is made during the third trimester by the placenta.

The rate of progesterone varies from woman to woman and from pregnancy to pregnancy. According to doctors, when this level is low, the chances of abortion in early pregnancy and premature birth increase. Progesterone is also responsible for the famous nausea of pregnancy. As if that weren't enough, it causes sleep, salivation and mood swings.