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Tests of functional diagnostics
Last reviewed: 19.10.2021
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To determine the characteristics of the menstrual cycle and endocrine influences, studies are conducted using functional diagnostic tests. Currently, only the basal temperature record is used from all tests. The woman is offered to measure basal (rectal) temperature every morning to the toilet and apply the data to a special schedule. In case of miscarriage, the basal temperature chart should be kept for the duration of the examination and preparation for pregnancy, noting the time of taking medications, other types of treatment, and also research. This allows you to evaluate the effect of therapeutic measures on the nature of the menstrual cycle (changing the time of ovulation, the duration of the phases of the cycle) and compare the results of other studies with the characteristics of the menstrual cycle. In addition, according to the basal temperature schedule, you can suspect the presence of early pregnancy. The increase in basal temperature in the middle of the menstrual cycle by more than 0.5 degrees indicates the presence of an ovulatory cycle. Most often in women with habitual miscarriage, a two-phase cycle with an inferior II phase is found. Thus the basal temperature can be of two variants. With the first option, a sufficient temperature rise is observed, but the II phase is short - from 4 to 6 days. The study of the level of excretion of pregnanediol in women with this cycle showed that its level is within the norm, but a shorter time. In the study of the endometrium on the 18-22 day of the cycle, the initial phase of secretion was revealed.
The second variant of insufficiency lies in the fact that there is a barely noticeable rise in basal temperature with a slow decline, but its duration corresponds to the normal II phase. With this variant of II phase failure, ovulation occurs in the middle of the menstrual cycle, the temperature rises at the same time, but it is very small, sometimes with changes, the temperature is unstable. In urine, a low level of excretion of pregnanediol is found.
Often the amount of progesterone produced is so small that it is difficult to determine the presence of phase II from the results of a cytological examination of a vaginal smear. With endometrial biopsy, this variant of phase II deficiency shows a weak development of secretory changes. Often when miscarriages, ovulatory cycles with an incomplete II phase alternate with anovulatory cycles that are characterized by a monophasic basal temperature without lifting, the absence of excretion of pregnanediol in the second half of the menstrual cycle and the presence of only proliferative changes in the endometrium. Clinical manifestations of the inferior phase II of the cycle can be caused both by a decrease in gonadal function and by damage to the target organ-endometrium due to a decrease in the activity of the receptors realizing the effect of sex hormones. Differentiate these states allow the study of the level of hormones in the blood in different phases of the menstrual cycle. In connection with the availability of hormonal studies to assess the quality of the menstrual cycle, other tests of functional diagnostics (cytology of vaginal smears, examination of the mucus of the cervical canal, the determination of the cervical number) are of historical interest.