What the heck is a Pregnanediol test?

This test measures pregnanediol, a metabolite of progesterone. It is used in the evaluation and decision making in women who are having difficulty becoming pregnant or maintaining a pregnancy. It is also used to monitor “high-risk” pregnancies.

Urinary pregnanediol is measured to evaluate progesterone production by the ovaries and placenta. The main effect of progesterone is on the endometrium. It initiates the secretory phase of the endometrium in anticipation of implantation of a fertilized ovum.

Usually, 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.

Pregnanediol is the most easily measured metabolite of progesterone. Because pregnanediol levels rise rapidly after ovulation, this study is useful in checking whether ovulation has occurred and, if so, exactly when. During pregnancy, pregnanediol levels normally rise because of placental production of progesterone. Repeated testing can be used to monitor the status of the placenta in women who have difficulty becoming pregnant or maintaining a pregnancy. Repeated testing can also be used to monitor the status of the placenta in high-risk pregnancy. Hormone testing for urinary pregnanediol are primarily used to monitor progesterone supplementation in patients with an inadequate luteal phase to maintain an early pregnancy. Urinary assays may be supplemented by plasma testing, which are quicker and more accurate.

Reference ranges:

Younger than 2 years: < 0.1 mg/ day
Younger than 9 years: < 0.5 mg/ day
10– 15 years: 0.1– 1.2 mg/ day
Adult male: 0– 1.9 mg/ day
Adult female:
Follicular phase: < 2.6 mg/ day
Luteal phase: 2.6– 10.6 mg/ day
Pregnancy:
First trimester: 10– 35 mg/ day
Second trimester: 35– 70 mg/ day
Third trimester: 70– 100 mg/ day

References

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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