Functional diagnostic tests

To determine the characteristics of the menstrual cycle and endocrine influences, studies are conducted using functional diagnostic tests. Currently, of all the tests, only basal temperature recording is used. A woman is asked to measure her basal (rectal) temperature every morning before going to the toilet and enter the data on a special chart. In case of miscarriage, a basal temperature chart should be kept throughout the entire examination and preparation for pregnancy, noting the time of taking medications, other types of treatment, and studies. This allows you to assess the effect of therapeutic measures on the nature of the menstrual cycle (changes in ovulation time, duration of cycle phases) and compare the results of other studies with the characteristics of the menstrual cycle. In addition, the basal temperature chart can be used to suspect the presence of early pregnancy. An 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, women with habitual miscarriage have a two-phase cycle with an incomplete phase II. In this case, the basal temperature can be of two types. In the first variant, there is a sufficient rise in temperature, but the II phase is short - from 4 to 6 days. The study of the level of excretion of pregnanediol in women with such a cycle showed that its level is within the normal range, but for a shorter time. When examining the endometrium on the 18-22 day of the cycle, the initial phase of secretion was detected.

The second variant of insufficiency is that there is a barely noticeable rise in basal temperature with a slow decline, but its duration corresponds to the normal II phase. In this variant of phase II insufficiency, ovulation occurs in the middle of the menstrual cycle, the temperature rise occurs at the same time, but is very small, sometimes with drops, the temperature is unstable. A low level of pregnanediol excretion is detected in the urine.

Often the amount of progesterone produced is so small that it is difficult to determine the presence of phase II based on the results of a cytological examination of a vaginal smear. In an endometrial biopsy with this variant of phase II deficiency, weak development of secretory changes is noted. Often, in case of miscarriage, ovulatory cycles with an incomplete phase II alternate with anovulatory cycles, which are characterized by a monophasic basal temperature without increases, the absence of pregnanediol excretion in the second half of the menstrual cycle, and the presence of only proliferative changes in the endometrium. Clinical manifestations of an incomplete phase II cycle can be caused by both a decrease in gonadal function and damage to the target organ - the endometrium due to a decrease in the activity of receptors that implement the action of sex hormones. Studies of the level of hormones in the blood in different phases of the menstrual cycle allow us to differentiate these conditions. Due to the current availability of hormonal studies to assess the quality of the menstrual cycle, other functional diagnostic tests (vaginal smear cytology, cervical mucus examination, determination of cervical number) are currently of historical interest.