FSH – follitropin (follicle‑stimulating hormone) stimulates the growth and maturation of ovarian follicles containing an egg.

Purpose of the test: to assess ovarian reserve, evaluate pituitary function, and support the diagnosis of menstrual cycle disorders.

LH – lutropin (luteinizing hormone). Its sudden increase triggers the completion of egg maturation and is essential for the rupture of the Graafian follicle. After ovulation, it stimulates the corpus luteum to produce progesterone.

Purpose of the test: detection of the pre‑ovulatory LH surge.

The ratio of FSH to LH concentrations should be close to 1. In cases of pituitary insufficiency, it decreases below 0.6, while in polycystic ovary syndrome, it rises above 1.5.

PRL – prolactin, a pituitary hormone. When its concentration increases, the levels of gonadotropins decrease, which interferes with the mechanism of ovulation. It can also lead to luteal (post‑ovulatory) phase insufficiency.

Prolactin levels remain relatively constant throughout the menstrual cycle, but they vary during the day – they are higher at night during sleep. Prolactin levels also increase due to stress, physical exercise, after a meal, and during pregnancy and breastfeeding.

Therefore, the test should be performed in the morning, on an empty stomach or at least 3 hours after a meal, and after a few minutes of rest.

Purpose of the test: diagnosis of ovulation mechanism disorders and luteal phase disorders.

Conversion factor: 1 ng/mL = 20 mIU/L.

E2 – estradiol, produced by the developing Graafian follicles, specifically by their granulosa cells.

Its level changes significantly throughout the menstrual cycle.

Purpose of the test: to assess ovarian reserve (together with FSH), evaluate follicular maturation dynamics, assess corpus luteum function, and support ovulation monitoring.

Conversion factor: 1 pg/mL = 3.67 pmol/L.

Progesterone is secreted by the corpus luteum formed from the ovarian follicle that ruptures during ovulation, by the placenta during pregnancy, and in trace amounts by the adrenal glands. Progesterone is responsible for preparing the endometrium for embryo implantation, maintaining appropriate conditions for the development of pregnancy, and – when its concentration falls after the endometrium has fully matured – triggering menstruation.

Progesterone levels begin to rise 40-16 hours before the LH peak, and peak secretion occurs approximately 8 days after ovulation.

Purpose of the test: assessment of corpus luteum function and monitoring of early pregnancy.

Conversion factor: 1 ng/mL = 3.18 nmol/L.

For the test to be reliable, it should ideally be repeated three times, because progesterone is secreted in a pulsatile manner and its blood concentration can fluctuate by as much as 50% within a few hours. The progesterone level does not fully reflect the degree of endometrial preparation. To determine deficiencies in this regard, an endometrial biopsy must be taken on a specific day of the luteal phase, or an ultrasound examination should be performed.

TSH – thyrotropin (thyroid‑stimulating hormone), which stimulates the production of the thyroid hormones T3 and T4.

T4 – thyroxine, the main hormone produced by the thyroid gland.

T3 – triiodothyronine, produced in small amounts by the thyroid; most of it is generated through the conversion of T4.

FT4 – free thyroxine, the biologically active, unbound form of the hormone T4.

FT3 – free triiodothyronine.

The test can be performed on any day of the menstrual cycle; however, it is usually done on day 3 of the cycle.

Hypothyroidism significantly reduces fertility. With a mild deficiency of thyroid hormones, conception is still possible, but pregnancy carries an increased risk of miscarriage and preterm birth. Maternal hypothyroidism may also adversely affect both the function of the developing fetal thyroid gland and the development of the fetal central nervous system. Hypothyroidism (elevated TSH) also indirectly promotes excess prolactin production, which further impairs fertility.

Hyperthyroidism does not directly suppress fertility, but an excess of thyroid hormones may block estrogen receptors and reduce their effectiveness, including in preparing the endometrium for implantation. Hyperthyroidism may also lead to pregnancy complications such as hypertension, preeclampsia, and cardiovascular disturbances.

Purpose of the test: detection of hypothyroidism or hyperthyroidism.

Testosterone, the androgen with the strongest biological activity. It is produced mainly from androstenedione (approx. 60%). The remaining amount is produced directly by the ovaries and adrenal glands (about 20% each).

Purpose of the test: testosterone measurement is used to confirm hirsutism, diagnose PCOS, and help identify the causes of excess testosterone in the body.

Androstenedione (A4), a weaker androgen, is produced in roughly equal proportions by the ovaries and adrenal glands.

Purpose of the test: diagnosis of PCOS and adrenal dysfunction.

Dehydroepiandrosterone (DHEA) and its sulfate DHEAS are weaker androgens produced almost exclusively by the adrenal glands (over 90%), with only trace amounts produced by the ovaries.

Purpose of the test: helps determine whether excess testosterone originates from the adrenal glands or the ovaries.

SHBG (Sex Hormone Binding Globulin) is a protein that binds and transports sex hormones (testosterone, estradiol) in the bloodstream.

Purpose of the test: confirmation of excess biologically active testosterone, diagnosis of PCOS, or hyperthyroidism.

17‑Hydroxyprogesterone (17‑OHP) is produced exclusively by the adrenal glands in the first phase of the menstrual cycle, and in the second phase also by the corpus luteum.

Purpose of the test: diagnosis of congenital adrenal hyperplasia (adrenogenital syndrome).

Androgen levels remain relatively stable throughout the menstrual cycle, except around ovulation, when their concentrations increase. However, the test is usually performed on day 3 of the menstrual cycle.

hCG – human chorionic gonadotropin is a hormone produced by the chorionic tissue of the placenta. It is secreted by the blastocyst after implantation in the uterus and by the developing chorionic villi. hCG supports the function of the corpus luteum in early pregnancy (up to weeks 8–10). If implantation of a fertilized egg occurs (typically between 6-8 days after ovulation), a detectable concentration of hCG (>1 mIU/mL) appears in the blood approximately 48 hours later.

Purpose of the test: detection of early pregnancy, monitoring the effectiveness of treatment for ectopic pregnancy, and surveillance during the management of hydatidiform mole or trophoblastic tumors.

More important than the absolute hCG values are the changes in its concentration over time. In a normal pregnancy, hCG levels increase by at least 66% within 48 hours and by 114% within 72 hours. hCG reaches its peak around the 8th–10th week of pregnancy, after which its concentration decreases and remains lower for the rest of the pregnancy.

AMH – Anti‑Müllerian Hormone is secreted by Sertoli cells of the gonads, meaning the ovaries in women and the testes in men. The level of this hormone in the blood allows for the assessment of a woman’s fertility, estimation of the chances of conceiving, and confirmation of the menopausal stage.

Purpose of the test: evaluation of ovarian function and assessment of ovarian reserve.

Endometrial assessment is performed using ultrasound imaging. The decidual cells and the EMJ (endometrial–myometrial junction) form a functional unit essential for proper implantation and the maintenance of pregnancy.

Purpose of the test: evaluation of the physiological changes within the endometrium and its ability to support implantation, pregnancy development, and full‑term gestation.

Cycle (ovulation) monitoring is an ultrasound examination that allows for the assessment of the growth of ovarian follicles containing the oocyte, as well as the evaluation of ovulation and its timing. The examination is performed several times during the cycle – in the follicular phase, the peri‑ovulatory phase, and the post‑ovulatory phase – to confirm that ovulation has occurred.

Purpose of the test: assessment of developing ovarian follicles and confirmation of ovulation and endometrial development.

A semen analysis evaluates the basic parameters of a man’s ejaculate, including the total sperm count, sperm concentration, and the assessment of sperm motility and viability.

Before the test, a period of sexual abstinence is required (3–5 days).

Purpose of the test: evaluation of the overall quality and normality of a man’s semen.

* To classify a semen sample as normal, it was sufficient for only one of these values to fall within the reference range.

The above WHO recommendations were established based on a reference group of more than 4,500 men aged 30 years (±5), whose partners conceived within less than one year of attempting pregnancy.

It should be noted that a semen analysis should be confirmed by at least two separate tests, as semen quality undergoes physiological variability influenced by various external factors and medical conditions.

Furthermore, these reference ranges should not be interpreted too rigidly, as natural conception is still possible in men whose results fall below the established norms.

Karyotype testing (cytogenetic analysis) is one of the examinations used in the evaluation of infertility or recurrent miscarriages. It is performed in both women and men.

The test determines the number and structure of a person’s chromosomes. As a result of cytogenetic analysis, a karyotype is obtained – an image of the chromosomes present in each cell of the body. In a healthy individual, each cell should contain 22 pairs of autosomes and 2 sex chromosomes. In total, every healthy person has 46 chromosomes in a single cell. Any deviation from the normal karyotype is associated with serious genetic disorders (sex chromosome or autosomal aberrations) and, through disturbances in gamete production, may also be a cause of infertility.

Purpose of the test: to determine whether fertility problems have a genetic basis.

Who should undergo karyotype testing?

• women after miscarriages, especially recurrent ones;
• women with primary amenorrhea or pubertal development disorders;
• couples struggling with infertility;
• women who previously gave birth to a child with a genetic disorder;
• men suspected of sex chromosome abnormalities;
• individuals with a family history of genetic diseases.