Pregnanediol is 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. Pregnanediol levels are very close to Progesterone Levels.
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. Normally, 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 documenting whether ovulation has occurred and, if so, exactly when. This is useful information for a woman who has difficulty becoming pregnant. During pregnancy, pregnanediol levels normally rise because of placental production of progesterone. Repeated assays can be used to monitor the status of the placenta in high-risk pregnancy.
Hormone assays 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 assays (progesterone assay), which are quicker and more accurate.
Normal Pregnanediol Levels
Normal Pregnanediol Levels increase by age. Adult females have the highest normal Pregnanediol levels. In adult females, Pregnanediol levels vary during the menstrual cycle and they increase during pregnancy. The following is a listing of Normal Levels of total Pregnanediol in 24 hours urine collection:
Children younger than 2 years: less than 0.1 mg/24 hours.
Children between 3 and 9 years: less0.5 mg/24 hours.
Children between 10 and 15 years: Between 0.1 and 1.2 mg/24 hours.
Adult males: None or less than 2 mg/24 hours.
Normal Pregnanediol Levels in Adult Female
During Follicular Phase: less 2.6 mg/24 hours.
During Luteal Phase: Between 2.6 and 10.6 mg/24 hours.
Pregnancy First Trimester: Between 10-35 mg/24 hours..
Pregnancy Second Trimester: Between 35 and 70 mg/24 hours..
Pregnancy Third Trimester: Between 70 and 100 mg/24 hours.
Drugs that Affect Prenanediol Levels
- Drugs that may cause increased levels include Adrenocorticotropic Hormone (ACTH).
- Drugs that may cause decreased levels include Oral Contraceptives and Progesterone.
Causes of High Pregnandiol Levels
- Ovulation: Ovulation occurs with development of a corpus luteum, which makes progesterone. Pregnanediol is a metabolite of progesterone.
- Pregnancy: A healthy placenta produces progesterone. Pregnanediol is a metabolite of progesterone.
- Molar Pregnancy: Hydatidiform mole can produce progesterone, although at lower levels than during pregnancy.
- Luteal Cysts of Ovary: The corpus luteum produces progesterone in the nonpregnant woman and in the early stages of pregnancy. Cysts can also produce progesterone for prolonged periods of time. Pregnanediol is a metabolite of progesterone.
- Arrhenoblastoma of Ovary: This tumor can secrete sex hormones or their metabolites (usually testosterone). 17-Hydroxyprogesterone is a precursor of sex hormones. Pregnanediol is a metabolite of progesterone.
Hyperadrenocorticism or Adrenocortical Hyperplasia: Adrenal cortical hormones are secreted at increased rates. 17-Hydroxyprogesterone is a precursor of these cortical hormones. Pregnanediol is a metabolite of progesterone.
- Choriocarcinoma of Ovary: This tumor produces progesterone.
Causes of Low Pregnandiol Levels
The following obstetrical emergencies are associated with decreased placental viability. Progesterone is made by the placenta during pregnancy. Pregnanediol is a metabolite of progesterone, which is decreased when placental viability is threatened:
- Toxemia of Pregnancy.
- Threatened Abortion.
- Placental Failure.
- Fetal Death.
Ovarian neoplasm: Ovarian epithelial cancers can destroy functional ovarian tissue. Progesterone levels may decrease.
Amenorrhea, or Ovarian Hypofunction: Without ovulation, a corpus luteum will not develop. Progesterone will not be secreted, and progesterone and pregnanediol levels will be lower than expected.