What is Pregnanediol (b-Pregnanediol)? Definition + Reference Ranges

Pregnanediol is an inactive product that forms when the body breaks down the hormone Progesterone. In women, Progesterone is produced mainly after the ovaries release an egg (ovulation). Because Pregnanediol levels rise rapidly after ovulation, this study is useful in documenting whether ovulation has occurred and, if so, when. Formed mainly in the liver, it appears in part in the urine, where it can be measured to determine the degree of ovarian function. This is useful information for a woman who has difficulty becoming pregnant. During pregnancy, Pregnanediol levels (more detailed info here) normally rise because of placental production of progesterone.

Pregnanediol low high reference range fsh oestrogen lh progesterone

Quick Facts:

  • Progesterone is secreted by the ovarian corpus luteum after ovulation.
  • Both serum Progesterone levels and urine concentration of progesterone metabolites (pregnanediol and others) are significantly increased during the second half of an ovulatory cycle.
  • When Pregnanediol levels fall during a menstrual cycle, it means that progesterone levels are less than ideal. It results in symptoms during the luteal phase.

The main function of progesterone is to help the uterus prepare for possible implantation of a fertilized egg. After fertilization, progesterone is necessary for the development of the placenta, the organ that develops to nourish the growing baby. During pregnancy, most progesterone is produced by the placenta.

During the adaptation of the body to menopause, Progesterone levels fall and estrogen dominance begins. That’s when Progesterone supplements may be offered to manage the symptoms. Some of the symptoms include hot flashes, vaginal dryness, mood instability, low sex drive, sleep problems, brain fog, hair loss, loss of muscle mass and strength, weight gain and anxiety.

Normal Ranges for Pregnanediol in mg/day:

Men: 0-1.9 mg/day

Women: Follicular phase:  <2.6 mg/day

Luteal phase: 2.6-10.6 mg/day

Children 10-15 years old: 0.1-1.2 mg/day

<9 years old: <0.5 mg/day

<2 years old: <0.1 mg/day


First trimester: 10-35 mg/day

Second trimester: 35-70 mg/day

Third trimester: 70-100 mg/day

Find out what it means if your Pregnanediol levels are too high or too low @


Lobo RA. Reproductive endocrinology: neuroendocrinology, gonadotropins, sex steroids, prostaglandins, ovulation, menstruation, hormone assay. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM, eds. Comprehensive Gynecology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2007:chap 4.

Lehmann HP, Henry JB. SI units. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:appendix 5.

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