Diagnostic Tests for Female Infertility
To determine the underlying cause of infertility in women, multiple diagnostic tests are required, as no single test can independently identify the cause of infertility. Measuring the serum levels of key hormones—including FSH, LH, estrogen, progesterone, estradiol, prolactin, AMH, testosterone, DHEA, androstenedione, and 17-OH-progesterone—is essential. The optimal time for assessing most of these hormones is on the third day of the menstrual cycle.
To minimize the risk of inaccurate results, pre-test preparation and adherence to specific testing conditions are critical. Some tests require fasting or must be conducted at a specific interval after waking. Others may be performed at any time of day, as timing does not significantly affect the results. In many cases, hormonal imbalances may present no overt clinical symptoms, and abnormalities are only detected during infertility assessments.
Among the hormones tested, FSH, LH, progesterone, estrogen, and prolactin receive particular attention due to their pivotal roles in reproductive health. Additionally, thyroid function tests are crucial in the diagnostic workup for infertility, as both hypothyroidism and hyperthyroidism can interfere with ovulation and contribute to infertility. For example, elevated TSH combined with low free T4 levels can lead to increased prolactin levels, which in turn suppress ovulation. In such cases, prolactin levels often return to normal following appropriate treatment of the thyroid disorder.
Although testosterone is typically considered a male hormone, small quantities are naturally produced by the adrenal glands and ovaries in women. Elevated testosterone levels may be observed in women with polycystic ovary syndrome (PCOS).
FSH (Follicle-Stimulating Hormone) is responsible for the maturation and development of ovarian follicles. Measuring FSH levels on day 3 of the menstrual cycle provides valuable diagnostic insight into ovarian reserve.

Progesterone, secreted by the adrenal glands and ovaries, is a critical hormone for preparing the uterus for embryo implantation. It thickens the endometrial lining to create optimal conditions for implantation. After conception, beginning around the tenth week of pregnancy, the placenta assumes responsibility for progesterone production to support pregnancy continuation. A decline in progesterone levels can cause the endometrial lining to shed, resulting in miscarriage.
Among the key functions of estrogen are the stimulation of uterine and fallopian tube growth, development of mammary ducts, and secretion of cervical mucus.
AMH (Anti-Müllerian Hormone) levels remain low in girls until the onset of puberty, after which ovarian production begins. The primary clinical value of AMH testing lies in estimating ovarian reserve and predicting fertility potential. Elevated AMH levels are commonly seen in women with PCOS.