Clinical significance: Progesterone, a steroid hormone with a molecular weight of 314.5 daltons, progesterone is primarily synthesized in the cells of the corpus luteum and, during pregnancy, in the placenta. progesterone is barely detectable in follicular phase of menstrual cycle, a rise in the progesterone level is observed one day prior to ovulation .
Functions of progesterone
Progesterone induces secretory changes in endometrium for implantation of the fertilized ovum.
In the mammary gland, progesterone together with estrogens promotes the proliferation and secretion disposition of the alveoli
progesterone inhibits myometrial contraction and maintains pregnancy1.
Clinical uses:
- Obtain an indication of the day of ovulation
- Evaluate the functional state of the corpus luteum in infertility patients
- Assess placental function during pregnancy
- To evaluate patient at risk for early abortion
The determination of progesterone is utilized in fertility diagnosis for the detection of ovulation and assessment of the luteal phase.
Interpretation:
Progesterone levels are reported in nanograms per milliliter (ng/mL) or sometimes in nanomoles per liter (nmol/L).
Normal progesterone levels in non-pregnant women during the luteal phase are typically above 5 ng/mL. However, specific reference ranges may vary between laboratories.
Increased in: luteal phase , luteal cyst of ovary, molar pregnancy, adrenal cortical hyperplasia ,adrenal tumors, ovarian tumors
Decreased in: Amenorrhea, fetal demise, placental failure, toxemia of pregnancy, gonadal agenesis, threatened abortion.
Reference range of serum progesterone
| females | Reference range |
| follicular phase | <0.05-0.193 ng/ml |
| ovulatory phase | 0.05-4.14 ng/ml |
| luteal phase | 4.11-14.5 ng/ml |
| pregnancy | |
| first trimester | 11-44.3 ng/ml |
| second trimester | 25.4-83.4 ng/ml |
| third trimester | 58.7-214 ng/ml |
| Postmenopausal women | <0.05-.013 ng/ml |
| Male | 0.0−0.5 |
Limitations:
Immunoassay test may exhibit interference when the sample is collected from a person who is consuming a high dose of biotin (>5mg/day) Patients should be cautioned to stop biotin consumption at least 8 hours before collection of the sample.
In rare cases heterophile antibodies in serum can react with reagent immunoglobulin and cause interference in results, particularly seen in persons exposed to animals and animal serum products.
References:
1. Johnson MR, Carter G, Grint C, Lightman SL. Relationship between ovarian steroids, gonadotrophins and relaxin during the menstrual cycle. Acta Endocrinol. 1993 Aug; 129(2):121-125. PubMed 8372595
Wallach’s interpretation of diagnostics tests, 12th edition.
Mosby’s Diagnostic and Laboratory Test Reference, 15th Edition