Progesterone (Serum)
Progesterone rises rapidly in early pregnancy and is essential for maintenance of early gestation. In later pregnancy, the placenta becomes the primary source.
| Units | Menstruating Female | 1st Trimester | 2nd Trimester | 3rd Trimester |
|---|---|---|---|---|
| ng/mL | < 0.2 (follicular) 3 – 20 (midluteal) |
8 – 48 | (—) | 99 – 342 |
| nmol/L | < 0.6 (follicular) 9.5 – 63.6 (midluteal) |
25.4 – 152.6 | (—) | 314.8 – 1087.5 |
Pregnancy Physiology
- Early pregnancy progesterone is produced by the corpus luteum.
- Placental production becomes dominant after ~10 weeks gestation.
- Progesterone promotes uterine quiescence, increased maternal ventilation, and breast development.
- Levels rise steadily through pregnancy and plateau late in the third trimester.
- After the first trimester, serum level alone does not reliably predict pregnancy viability.
Causes of LOW Progesterone
- Early pregnancy failure or threatened miscarriage
- Luteal phase deficiency
- Ectopic pregnancy
- Placental insufficiency
- Fetal demise
- Ovarian suppression from medications
- Severe maternal illness or malnutrition
Causes of HIGH Progesterone
- Multiple gestation
- Molar pregnancy
- Luteal cysts
- Congenital adrenal hyperplasia
- Progesterone supplementation (oral, vaginal, IM)
- Adrenal or ovarian tumors (rare)
References
- Kratz A, Ferraro M, Sluss PM, Lewandrowski KB. N Engl J Med. 2004;351:1548–1563.
- Abbassi-Ghanavati M, Greer LG, Cunningham FG. Obstet Gynecol. 2009;114:1326–31.