Estradiol (E2) is the most effective estrogen of the estrogen hormone family and is the female fertility hormone. It influences the maturation of the follicles and acts mainly as a growth hormone for the reproductive structures in females. The amount of estrogen produced depends on the phase of the menstrual cycle. When the ovaries are functioning well, estradiol levels are relatively low around day three of the menstrual cycle and are therefore referred to as baseline estradiol levels.
Estradiol is not considered a marker for ovarian reserve but serves only to interpret FSH levels. A normal estradiol with a normal FSH indicate normal ovarian reserve (egg quality and quantity) and normal age-related fertility potential. Since high estradiol levels can artificially suppress FSH levels, it is important to test not just FSH, but also estradiol with it. High estradiol with a normal or elevated serum FSH might be a sign that ovarian reserve is diminished, thus reducing a woman’s ability to get pregnant.
Abnormally high estradiol levels in women who are not pregnant may be a sign of a possible underlying health problem. It might indicate endometriosis or reduced occurrence of ovulation.
Extremely low or no detectable estradiol levels can cause a range of symptoms like vaginal dryness, headaches, lowered libido, and reduced bone density.
LH (Luteinizing Hormone) is a hormone produced by pituitary gland and helps the reproductive system in both men and women. It plays a role in puberty, menstruation, and fertility. In women, LH levels change with age and throughout the menstrual cycle. There is a sudden increase between the 12th and 14th day of the menstrual cycle that triggers ovulation. A normal value usually means that there is enough estradiol and progesterone available and that the ovaries are not yet restricted in their function. An increased FSH level in combination with a normal LH level can, however, also occur during the menopause and shows that the ovaries still have residual function.
Slightly elevated levels of LH, alongside elevated FSH levels, suggest impaired ovarian reserve (poor egg quantity and quality) that accompanies chronological aging and might predict a lower chance for a successful pregnancy. Abnormally high levels of LH during nonovulatory times or persistently high levels can indicate that you have entered menopause. During menopause, the LH value rises to five times, but it can be subject to strong fluctuations. After menopause, the LH level remains slightly elevated.
FSH is a hormone associated with the reproductive system both in men and women. In women, it is responsible for growth and maturation of ovarian follicles, which produce estrogens and progesterone to maintain a normal menstrual cycle. Since estradiol levels on day 3 on the menstrual cycle naturally suppress FSH, relatively low levels within normal range in in conjunction with normal day 3 estradiol indicate normal ovarian reserve (egg quality and quantity) and normal age-related fertility potential.
In contrast, slightly elevated levels of FSH, alongside elevated LH levels, suggest impaired ovarian reserve (poor egg quantity and quality) that accompanies chronological aging and might predict a lower chance for a successful pregnancy. In women with naturally declining ovarian reserve and a reduction in function of the ovaries elevated FSH usually also stimulate higher estradiol levels. In premenopausal age elevated FSH alongside elevated estradiol might also be suspicious for functional cysts that do not affect fertility and mostly naturally go away on their own.
Marginally elevated FSH levels can also be caused by stress or by being underweight.
Thyroid Stimulating Hormone (TSH) is a hormone produced by the pituitary gland in the brain that controls thyroid hormone production. Thyroid hormones are crucial for regulating metabolism, energy production and play a big part in fertility and pregnancy. Normal TSH levels generally indicate a normally functioning thyroid gland that does not interfere with a woman’s ability to get pregnant.
Decreased levels are caused by hyper- or hypothyroidism. Abnormalities in thyroid function are known to have an adverse negative effect on reproductive health and are associated with an increased risk of unexplained fertility and recurrent miscarriage. Low levels of TSH should always be followed up by measuring the thyroid hormones, i.e., thyroxine (T4) and triiodothyronine (T3). Slightly decreased levels can result from subclinical hyper- or subclinical hypothyroidism. These are early, mild forms of thyroid disorders that might interfere with a woman’s ability to get pregnant.
Slightly increased levels on the other hand can result from subclinical hypo- or subclinical hyperthyroidism. These are as well, early, mild forms of thyroid disorders that might interfere with a woman’s ability to get pregnant.
Extremely high TSH is usually accompanied by altered thyroid hormone levels. This is associated with a disturbed maturation of the ovarian follicle, a lower fertilization rate, and lower embryo quality, thus leading to unexplained fertility and recurrent miscarriage. High levels as well as low levels should always be followed up by measuring the thyroid hormones, i.e., thyroxine (T4) and triiodothyronine (T3).
The hormone prolactin is formed in the front part of the pituitary gland and reaches its place of action via the blood system. This is primarily the female mammary gland: prolactin promotes its growth and, after childbirth, the production and secretion of breast milk. In addition, during pregnancy and breastfeeding, prolactin inhibits the menstrual cycle by preventing the release of various other hormones.
Prolactin levels are rarely decreased. The reason can be a dysfunction of the pituitary gland or the use of medications that lower prolactin. In most cases, a low prolactin level isn’t a problem. If a functional weakness of the pituitary gland can be ruled out as the cause, usually the doctor will just continue to check the prolactin level regularly. The doctor will also check whether any medication you may have been taking is responsible for the low levels.
Possible causes for an increased prolactin level (Hyperprolactinemia) can be:
- A deficiency of dopamine (dopamine works as an inhibitor of prolactin)
- Medication (such as hormonal contraceptives, antidepressants, blood pressure medication)
- A deficiency of thyroid hormones (hypothyroidism)
- A prolactin-forming tumor
- Severe kidney failure (renal insufficiency), leading to prolactin not being excreted sufficiently
- Increased levels of male sex hormones in women
But high prolactin levels can also be caused by other things like pregnancy and breastfeeding, but also physical or emotional stress.