Why are reproductive hormones important?
The female reproductive cycle is influenced by the relationships between several hormones especially follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2). The hypothalamus signals the pituitary to produce FSH which stimulates the recruitment and development of the ovarian follicles. As the follicles grow, they produce estradiol which signals the hypothalamus to regulate the pituitary’s production of FSH.
How are abnormal hormone levels interpreted?
When viable follicles are at a critically low number, signals from the ovary are low and more FSH is produced leading to elevated day 3 levels. A high FSH level on day three is one indication of reduced ovarian reserve or impending menopause. In general, diminished ovarian reserve is indicated by an FSH of greater than12, or a high E2 level (greater than 80 pg/ml). An elevated estrogen level may also be caused by an ovarian cyst. When the day 3 results are poor, and other tests such as the clomiphene citrate challenge test confirm diminished ovarian reserve, donor egg IVF or adoption should be pursued.
What is AMH?
Anti-mullerian hormone (AMH) is emerging as another sensitive test of fertility potential in women. This hormone is involved in the very early phase of follicle development in the ovary. One advantage of this test is that it can be performed on any day of the cycle or even while the woman is on hormonal medications, since it remains relatively constant. Low AMH levels (less than 0.3 ng/ml) indicate lower number eggs that will grow with fertility medications and lower chances of conceiving with IVF, compared to women with higher AMH.
What other hormones are evaluated in a new infertility patient?
Many other hormone levels are evaluated in the infertility workup. Elevated levels of androgens (male hormones) can cause irregular ovulation and are seen in obese women and those with polycystic ovary syndrome.
Thyroid hormone levels also influence fertility. Hypothyroidism (low levels) can cause anovulation and early pregnancy loss. Hyperthyroidism (high levels) is associated with irregular ovulation, fetal abnormalities, and premature labor.
Prolactin is the hormone responsible for stimulating breast milk production in pregnant women. Hyperprolactinemia means elevated prolactin in the absence of pregnancy and causes ovulation to become irregular or absent. This condition is usually caused by a benign tumor at the base of the brain that can be treated with medication (bromocriptine or cabergoline). Surgery is rarely necessary.
Levels of the hormone progesterone rise in association with ovulation. The follicle contains the mature egg and it ruptures when ovulation occurs. The remaining follicular structure is known as the corpus luteum. The corpus luteum secretes progesterone which supports the development of the endometrium and implantation.
An elevated progesterone level is one indication that ovulation has occurred. Progesterone is produced by the placenta once pregnancy is established. One week after ovulation, the level should be approximately 10 ng/ml.