B4. Functional diagnostics of the ovarian capacity, cycle diagnostic
These investigations are mostly relevant for the evaluation of infertility (see topic B12).
Medical history and labs
The regularity of the menstrual cycle is important in assessing the ovarian cycle. A cycle is considered normal when it comes every 24 – 38 days.
Elevated serum progesterone over a certain value (> 3 ng/mL or > 10 nmol/L) mid-luteal phase (day 21) is indicative of ovulation. If this increase does not occur, the patient has anovulation and should be investigated for it.
Over-the-counter urinary ovulation prediction kits which detect LH in the urine can also be used to predict the timing of the LH surge that indicates ovulation.
Ovarian reserve assessment
Decreased ovarian reserve refers to decreased oocyte quality, quantity, or reproductive potential. These techniques can estimate the number of eggs in the ovaries (ovarian reserve) and is useful in the management of infertility. They can guide the choice and amount of medication to be given.
The two most commonly used tests nowadays are anti-Müllerian hormone (AMH) measurement and antral follicle count (AFC).
AMH is produced by granulosa cells in preantral follicles and is constant throughout the cycle. Normal values are between 1,1 – 3,5. If the value is below this, the ovarian reserve is low, if above then the ovarian reserve is high.
Antral follicle count is an ultrasound measurement of the 2 – 10 mm follicles in the ovaries at the beginning of the cycle. This number correlates to the number of eggs. < 7 AFC means low ovarian reserve, > 20 AFC means high ovarian reserve.
Other tests of ovarian reserve include:
- FSH/oestradiol ratio on day 3
- Inhibit B level
- Clomiphene citrate challenge test
The ovarian reserve declines by approximately 5% per year.
Anatomic and endometrial evaluation
Evaluation of the endometrial thickness and phase by ultrasound is used.
Hysterosalpingography or sonohysterography may be used to evaluate the uterine and fallopian tubes for anatomical abnormalities, endometrial polyps, fallopian tube patency, etc.
Hysteroscopy and MRi may also be helpful.
Hormonal evaluation
Further hormonal evaluation of thyroid function, prolactin, and androgens may be useful as disorders of these are associated with adverse reproductive outcomes.
Basal body temperature test
Progesterone increases body temperature and is released after ovulation. By measuring the body temperature daily in the morning before doing anything which can alter the temperature (walk, eat) for multiple cycles, it’s possible to estimate when during the cycle ovulation occurs. However, the temperature increase occurs too late to be useful for timing intercourse.