Infertility
Infertility
A complex situation for the couple, which needs expertise, time and precision
The World Health Organization defines infertility as a disease of the reproductive system of the woman or the man: the couple does not achieve a pregnancy after 12 months of regular sex without contraception. For women aged 35 or over, this period is six months, and after 40 treatment should be discussed straight away. With an irregular cycle, endometriosis, previous surgery on the ovaries or tubes, or a known problem in the man, there is no reason to wait. Infertility affects about one in six people of reproductive age.
Infertility rarely has a single cause. Usually it is the result of many factors working together: age, hormones, metabolism, anatomy, and the quality of eggs and sperm. In 25% of couples more than one factor is present. A finding that would be harmless on its own can, together with a second one, prevent a pregnancy. This is why a list of tests is not enough. What matters is reading all the findings together, for each couple.
Many couples move quickly to IVF without a proper look at the hormonal background. IVF gets around some obstacles, but it does not treat the cause. An ovulation disorder, insulin resistance, a thyroid disorder or endometriosis affect egg quality, implantation and the course of the pregnancy, whether conception happens naturally or in the laboratory. Gynecological endocrinology focuses on exactly this background.
The factors behind infertility
How does conception happen?
Conception is a chain of steps, and each step depends on the one before. The brain (hypothalamus and pituitary gland) signals the ovaries to mature a follicle. This maturation starts about three months before ovulation. In the man, a sperm cell needs about 74 days to form.
After ovulation the egg lives only 12 to 24 hours, while sperm can survive up to five days. This is why the fertile days are the five days before ovulation and the day of ovulation itself. Fertilization takes place in the tube. The embryo reaches the uterus after five to six days and can implant only in a short “window”, when progesterone has prepared the lining of the uterus correctly.
Even when everything works well, the chance of pregnancy in one cycle is about 20-25% for a woman under 30. A cycle can look normal and still hide a problem: ovulation that does not happen every month, a weak luteal phase, or a lining that is not ready for implantation.
How do age and ovarian reserve affect fertility?
A woman's age is the single most important factor for fertility. A woman is born with a set number of eggs, and their number and quality keep falling. Quality mainly means whether the egg has chromosomal abnormalities. In a study of more than 9,000 embryos, 45-60% of embryos were euploid, meaning without chromosomal abnormalities, at 30 to 38, and about 25% at 41 to 42. This is why the risk of miscarriage also rises with age: from 15-20% at 25 to 29 to over 60% after 40. More in the article “Pregnancy at an older age”.
The doctor assesses ovarian reserve with the hormone AMH and by counting the follicles on ultrasound. These tests show how many eggs are left and how the ovaries will respond to stimulation. They do not show egg quality, and according to ESHRE they cannot predict whether a woman will get pregnant on her own. A 35-year-old woman with low AMH usually has a better outlook than a 42-year-old woman with normal AMH. Reading the values without age, history and cycle often leads to wrong conclusions, either needless panic or false reassurance. More in the article “Diminished ovarian reserve”.
When the ovaries stop working before 40, this is called premature ovarian insufficiency. According to ESHRE (2024), it affects about 3-4% of women, and it is not only a fertility issue. The woman needs tests to find the cause, and hormone replacement therapy to protect her bones, heart and brain. More in the article “Premature ovarian insufficiency”.
Age, time and assessment
When the assessment starts
What changes with age
Euploid embryos
Risk of miscarriage
Which hormonal causes affect the woman?
Ovulation disorders are the most common cause of infertility in women and also the cause for which treatment is most effective. The World Health Organization divides them into three groups, depending on where the problem lies, and this grouping decides the treatment.
When the brain gives no signal. Functional hypothalamic amenorrhea occurs with low weight, intense exercise, eating too little or severe stress. The body “switches off” reproduction to save energy. In these women the usual stimulation of the ovaries does not help. They need specialized treatment, above all restoring their energy balance. More in the article “PCOS and functional hypothalamic amenorrhea”.
When hormones are normal but ovulation does not happen. This group includes polycystic ovary syndrome, which explains the large majority of cases without ovulation. High androgens and insulin resistance do not only affect ovulation. They also affect egg quality, the lining of the uterus and the risk of complications in pregnancy. This is why inducing ovulation is only one part of the treatment. More in the article “PCOS and infertility”.
When the ovaries do not respond. This group includes premature ovarian insufficiency. The pituitary sends a strong signal, but the ovaries cannot answer.
Besides these three groups, other hormonal disorders also affect fertility. They affect not only how often ovulation happens, but also its quality, the preparation of the uterine lining for implantation and the exact timing between the two. This timing is essential for a pregnancy and for the birth of a healthy baby.
Hyperprolactinemia can disturb ovulation. Among thyroid conditions, what matters for fertility is overt hypothyroidism and certain forms of subclinical hypothyroidism. Thyroid antibodies matter mainly when there is a history of miscarriage. Not every woman needs thyroxine, and when it is given, it does not have to aim for specific values in every case.
Insulin resistance, high androgens and excess weight matter both for natural conception and in an IVF cycle. They also raise the risk of miscarriage and gestational diabetes.
The luteal phase, meaning the days after ovulation, is the stage when progesterone prepares the lining of the uterus. A single progesterone test is rarely enough to draw conclusions. What matters is the right timing, and reading the result together with the cycle and the history.
How do endometriosis and adenomyosis affect fertility?
40-50% of women with endometriosis have problems with fertility, and the disease often goes undiagnosed. It is not only a mechanical obstacle. The inflammation in the abdomen affects egg quality, tube function and implantation. Endometriotic cysts on the ovaries (endometriomas) need special care, because surgical removal lowers the ovarian reserve. Adenomyosis, where lining tissue grows into the muscle wall of the uterus, can reduce implantation and raise the risk of miscarriage. The choice between medication, surgery and IVF depends on age, reserve, pain and previous surgery. More in the article “Endometriosis and infertility”.
What role do the tubes and the uterus play?
Anatomical abnormalities of the uterus, disorders of the uterine lining and previous pelvic inflammation can reduce fertilization and implantation. When a tube is blocked and filled with fluid (hydrosalpinx), the fluid can reach the uterus and prevent implantation. According to the Cochrane systematic review, removing this tube before IVF increases the chance of pregnancy.
In the uterus, polyps, fibroids that press on the cavity, adhesions and differences in the shape of the uterus can affect implantation. Not every finding needs surgery, though. The decision depends on size, position and history. 3D ultrasound and hysteroscopy give the most accurate picture.
What role does the man play?
In about 50% of couples, the man is the only cause or one of the causes. A semen analysis is part of the work-up from the start, in a laboratory with quality control, using the criteria of the World Health Organization manual (2021). Because sperm quality varies, an abnormal result needs a repeat test after about three months.
Male fertility also depends on hormones. Sperm production depends on signals from the pituitary and on testosterone inside the testes. A common and underrated problem is the use of testosterone or anabolic steroids. This testosterone switches off the signals to the testes and can stop sperm production, and recovery takes months. Excess weight, diabetes, smoking, heat, infections and varicocele also affect sperm. After 50, the male factor may play a role in recurrent miscarriage. Age, however, seems to affect men differently from women in terms of sperm count and the ability to fertilize. When the semen analysis is abnormal, the work-up continues with hormone tests and, if needed, with a urologist or andrologist.
What if everything looks normal?
In some couples the basic work-up shows no cause. “Unexplained” does not mean there is no cause. It means the cause cannot be seen with the usual tests: egg quality, fertilization, tube function or implantation. Behind “unexplained” infertility there is often mild endometriosis, a metabolic disorder or a weak luteal phase that nobody looked for. More in the article “Unexplained infertility”.
Which tests does the woman need?
For each test, the 2023 ESHRE guideline sets out exactly whether it is recommended or not.
Ovulation. With a regular cycle, routine confirmation of ovulation is not needed according to ESHRE. When confirmation makes sense, suitable methods are a urine LH test, ultrasound or measuring progesterone in the middle of the second half of the cycle. The doctor always reads the result together with the cycle and the history.
Ovarian reserve. According to ESHRE, testing the ovarian reserve is not needed to find the cause of infertility. It is important, however, for planning assisted reproduction, because it affects the number of eggs collected.
The fallopian tubes. An X-ray of the tubes (HSG) and an ultrasound with contrast (HyCoSy) are reliable tests according to ESHRE, and they are equivalent. The choice depends on the doctor's experience and the woman's wishes. The ultrasound method avoids X-rays and anesthesia. A blood test for chlamydia antibodies helps to distinguish between women with a low and a high risk of blocked tubes. If the risk is high, imaging of the tubes is needed. The guideline does not recommend routine laparoscopy.
The uterus. ESHRE recommends 3D ultrasound to rule out anomalies of the uterus. MRI is not the first choice. When the cavity of the uterus is normal on ultrasound, no further tests are needed. Hysteroscopy has a place only when the ultrasound shows a finding. A biopsy of the uterine lining without a specific reason and the post-coital test are not recommended. Testing of the vaginal microbiota belongs only in research, according to the guideline.
Thyroid and celiac disease. Measuring TSH is part of good preparation for pregnancy. With a normal TSH, no further thyroid tests are needed. ESHRE does not recommend testing for thyroid antibodies and other autoimmune conditions. The exception is celiac disease: a test for it can be considered when the basic tests show no cause.
What is not recommended for the woman? ESHRE does not recommend testing for thrombophilia, measuring oxidative stress, genetic tests, measuring vitamin D for the diagnosis, or measuring prolactin in women with a regular cycle. Weight and BMI, on the other hand, are part of good preparation for pregnancy.
Which tests does the man need?
The main test for the man is the semen analysis. Even a mildly abnormal semen analysis means that there is a male factor, and the assessment of the man continues.
With a normal semen analysis, ESHRE does not recommend any further tests: no ultrasound of the testicles, no test for sperm antibodies in semen or blood, no test of sperm DNA fragmentation, chromatin condensation or sperm chromosomes, no hormone tests, no HPV test and no microbiological test of the semen. Measuring oxidative stress in semen belongs only in research.
What role does lifestyle play?
Weight, smoking and alcohol are proven to affect the fertility of both partners. Smoking brings menopause earlier and damages sperm. The World Health Organization recommends a healthy diet, physical activity and stopping smoking for all couples trying for a child. The woman should take folic acid for at least one month before conception.
What about the emotional side?
Infertility is a burden for the couple. The World Health Organization recognizes that it can cause anxiety, depression and isolation. A clear explanation of what is happening and a plan with concrete steps greatly reduce this burden. A couple who understands their situation makes better decisions.
ESHRE recommends making psychosocial support a routine part of every fertility treatment. A systematic review shows that emotional strain is one of the most common reasons why couples stop treatment too early, often before their chances are used up. Care for mental health is therefore part of the treatment.
Why does time matter?
In infertility, the doctor weighs every decision against time. Treating a hormonal cause is often the right path. But for a woman of 42, or a woman with a much reduced reserve, a long preparation can cost the chance of pregnancy. Expertise means knowing when targeted hormonal treatment is enough and when not a single month should be lost.
The practice's approach
The practice treats infertility as a complex hormonal and reproductive condition of the couple, not as a list of tests. Many years of working only in gynecological endocrinology and reproductive medicine, including in fertility centers, help the doctor find hormonal causes that are often missed.
The doctor reviews all of the couple's tests and reads them together, based on age, history and how long the couple has already been trying to conceive. The focus of the practice's strategy, however, is hormones: ovulation, the luteal phase, androgens and metabolism determine egg quality, the preparation of the uterine lining, implantation and the course of pregnancy.
The goal of the practice is to increase the chance of natural conception with targeted hormonal treatment. When assisted reproduction is needed, hormonal preparation can increase its chances of success, and the couple arrives at the fertility center with a complete picture and a better starting point. After unsuccessful insemination or IVF, the doctor reviews the whole file again as a second opinion and, on request, writes a report.
Behind every file of test results there is a couple with their own story. Knowledge and expertise make the difference when the couple feels that the doctor sees the whole picture and stays with them at every step.
Sources: World Health Organization – Guideline for the prevention, diagnosis and treatment of infertility (2025). WHO laboratory manual for the examination and processing of human semen, 6th edition (2021). ESHRE – Unexplained infertility (2023), Endometriosis (2022), Premature ovarian insufficiency (2024). American Society for Reproductive Medicine – Infertility: An Overview (2017). Huang TTF et al., Euploidy rates within blastocysts obtained from differently sized cohorts and age groups approximate a binomial distribution, F&S Reports 2025 (euploid embryos by age). Dhillon-Smith et al., New England Journal of Medicine 2019, TABLET trial (thyroid antibodies). Cochrane Review CD002125 (hydrosalpinx and IVF). Gameiro S et al., ESHRE guideline: routine psychosocial care in infertility and medically assisted reproduction, Human Reproduction 2015. Gameiro S et al., Why do patients discontinue fertility treatment? A systematic review of reasons and predictors of discontinuation, Human Reproduction Update 2012.