In women with a regular cycle lasting approx. 25-35 days, ovulation generally takes place. The duration of the menstrual cycle varies by 1-2 days at most in individual women. If the cycle is much shorter or longer, or if it is irregular, the development of the ovarian follicle to ovulation and beyond is often disrupted. In some cases, ovulation does not take place. To diagnose such cycle disorders, one cycle is assessed using ultrasound and hormone analysis.
The causes for such issues may lie in the ovaries themselves, or in the pituitary gland, which controls the ovaries. These functions are also influenced by other organs such as the thyroid gland, the adrenal cortex and the brain, as well as by medications. This is why various organs are also investigated as part of routine testing, and you are asked about any medications you use.