progesterone

Imagine a small chemical messenger in the body, quietly getting things ready for a possible pregnancy. That's progesterone. It is a hormone made mainly by the ovaries after ovulation and, during pregnancy, by the placenta. One of its main jobs is to help control the menstrual cycle and prepare the lining of the womb so a fertilized egg can grow.

This hormone is not only about pregnancy. It can also affect mood, sex drive, and bone health. Doctors may check its level to see whether ovulation has happened or to follow early pregnancy. It can also be given as medicine in some fertility or pregnancy treatments. In conversations about birth control, people often mention it too, although many pills use a similar lab-made hormone rather than the natural one.

Progesterone is a steroid hormone best known for its central role in reproduction, especially in the menstrual cycle and pregnancy. It is produced mainly by the ovaries, particularly by the corpus luteum after ovulation, and later by the placenta during pregnancy. Smaller amounts are also made in other parts of the body, such as the adrenal glands. Its most important job is to prepare the lining of the womb for a possible pregnancy. If no fertilized egg implants, the level falls, and this drop helps start menstruation.

During pregnancy, progesterone helps maintain the uterine lining and supports conditions that allow the fetus to develop. In simple terms, it helps the body stay ready for pregnancy instead of returning to a normal menstrual cycle. Because of this, doctors often pay attention to progesterone levels in fertility care and early pregnancy care.

This hormone also has effects beyond reproduction. It can influence mood, sleep, sex drive, and bone health, although these effects can vary from person to person. Low or changing levels may be linked to symptoms before a period, and testing may be used when doctors are checking ovulation or possible hormone problems.

In medicine, progesterone itself is sometimes prescribed, and similar lab-made hormones called progestins are widely used in birth control, hormone therapy, and some fertility treatments. The word therefore often appears in discussions about periods, ovulation, pregnancy, miscarriage risk, and reproductive health more broadly. It is a key hormone in the body’s system for preparing for and supporting pregnancy.