Progesterone (PROG)

What is Progesterone?

Progesterone is a steroid hormone primarily produced by the corpus luteum after ovulation and by the placenta during pregnancy. It prepares the uterine lining for implantation, maintains early pregnancy, and regulates the menstrual cycle. Small amounts are also produced by the adrenal glands.

Why is it Tested?

Doctors order progesterone to confirm ovulation, evaluate fertility issues, and investigate irregular menstrual cycles. It’s also used to assess pregnancy viability, diagnose luteal phase defects, and monitor hormone replacement therapy effectiveness.

Normal Ranges

Reference ranges vary by lab and menstrual cycle phase. General guidelines for women:

Follicular phase: 0.1–0.9 ng/mL
Luteal phase: 5–20 ng/mL
Postmenopausal: <1.0 ng/mL
First trimester pregnancy: 11.2–90 ng/mL

Timing of collection is critical for accurate interpretation.

Reference ranges vary by authority. Track yours across multiple standards with automatic unit conversions in LabsVault.

What do Abnormal Results Mean?

Abnormal results are not a diagnosis. Always discuss your results with a qualified healthcare provider before making any medical decisions.

Low Progesterone

Low levels may indicate:

Anovulation (lack of ovulation)
Luteal phase defect
Miscarriage risk
Menopause or perimenopause

High Progesterone

Elevated levels may suggest:

Successful ovulation
Early pregnancy
Ovarian cysts
Adrenal disorders

How to Track Over Time

Progesterone patterns reveal ovulation status and luteal phase adequacy. Tracking progesterone across multiple cycles helps identify ovulatory disorders, optimize fertility timing, and monitor reproductive health transitions like perimenopause.

Progesterone