The purpose of progesterone is to prepare the uterus for pregnancy, as well as maintaining pregnancy. Twelve weeks after gestation, the umbilical cord produces progesterone.
Progesterone is normally produced by the corpus luteum, peaking during the midluteal phase of the menstrual cycle. Progesterone levels are the best way to evaluate if ovulation occurred, health of the corpus luteum and chances of spontaneous abortion.
4-5 days after ovulation, progesterone levels rise and continue to do so in pregnancy for 9-32 weeks after gestation by as much as 100 times that of a non-pregnant female. Progesterone levels in females carrying twins are usually higher then single pregnancies. Progesterone levels used with β-HCG levels assists in assessing uterine pregnancies from ectopic pregnancies.
Progesterone levels are increased in:
- Congenital adrenal hyperplasia
- Lipid ovarian tumor
- Chorionnepithelioma of the ovary
- Molar pregnancy
Progesterone levels are decreased in:
- Threatened spontaneous abortion
- Galactorrhea-amenorrhea syndrome (hypogonadism)
Progesterone in the Follicular Phase plays a relatively minor but important role in preparing the body for ovulation and the possibility of pregnancy. The follicular phase is the first half of the menstrual cycle, starting from the first day of menstruation until ovulation (usually days 1–14 of a 28-day cycle). During this phase, the body focuses on preparing an egg for release, and estrogen plays a more dominant role in regulating the reproductive process.
Progesterone Levels in the Follicular Phase
The follicular phase is the first phase of the menstrual cycle, lasting from the start of menstruation to ovulation. During this phase, progesterone levels are typically very low because the corpus luteum (which produces progesterone) has not yet formed.
Normal Progesterone Levels in the Follicular Phase
- 0.1-0.7ng/mL 0.5-2.3 nmol/L
