Features of uterine blood flow in adolescents with abnormal uterine bleeding of puberty

The aim of this study was to study the ultrasound characteristics of the pelvic organs and the characteristics of uterine blood flow in adolescents with abnormal uterine bleeding during puberty. Methods: Investigate 93 adolescent girls with abnormal uterine bleeding during puberty (AUBDP), aged 11 to 18 years (mean age was 14.5 ± 3.5 years). Patients with AUBDP were divided into 2 clinical groups: I group consisted of 44 patients 11-14 years old, group II 49 adolescent girls 15-17 years old. The control group included 25 person of the same age without menstrual disorders. The frequency of relapses of AMKPP in group I was 20,4%, in group II – 28,5%. Ultrasound and Doppler study was performed using an ultrasound scanner "Siemens" (Germany), using a transabdominal sensor (3.5 MHz) and a transvaginal sensor (6.5-7 MHz) in adolescents who have sex. The conditional of blood flow in the uterine and spiral arteries was performed using Doppler study. The indices of vascular resistance in both the uterine and spiral arteries, the index resistance (IR), the pulsation index (PI), and the systolic-diastolic ratio (S/D) were calculated. Results: The study revealed hemodynamic changes in blood flow in girls with AUBDP. In this connection, the described changes in the parameters of blood flow in a. uterinae and a. radialis can serve as an additional diagnostic criterion for determining the risk of uterine bleeding during puberty. Conclusion: Based on the study, ultrasound and Dopplerometric features of the pelvic organs in adolescent girls with AUBDP were found, which were characterized by an increase in the size of the uterus, heterogeneous endometrial echostructure, an increase in the size of the ovaries, an increase in systolic and diastolic blood flow rates, and vascular resistance indices in a. uterinae and a. radialis


Introduction
Protection of reproductive health is one of the priority areas for the development of healthcare in Ukraine [1]. Menstrual dysfunction (MD) ranks high among gynecological diseases in adolescent girls, including the disorders associated with abnormal uterine bleeding of puberty (AUBP), which often leads to pathological conditions of menstrual and reproductive function in future [2,4].
The frequency of detection of AUBP in the structure of adolescent gynecological diseases is 10-37.5%, and is the reason of visiting a gynecologist in 30-40% [3,6]. Clinical manifestations of AUBP in the form of bleeding from the genital tract are accompanied by weakness, dizziness, posthemorrhagic anemia, resulting in reduced ability to work, psychological stress and depression, the impossibility to live a productive life. Subsequently, women with AUBP have a history of serious obstetric and perinatal complications [1,4,5,6]. Given the incidence, tendency to relapse, the impact on the reproductive health of a future woman, the problem of AUBP remains relevant and socially significant.
In the course of MD development, the main role belongs to changes in the functional state of the hypothalamic-pituitarygonadal complex. Moreover, blood supply to the pelvic organs also plays an important role [7].
Research methods are essential in the assessment of the condition of the internal genital organs of adolescent girls with AUBP. Thus, the methods of choice in pediatric and adolescent gynecology are ultrasound and Doppler studies, which require minimal preparation and do not cause psychological discomfort in patients. Currently, issues of the peculiarities of uterine blood flow in adolescent girls with AUBP remain unexplored [4].
The purpose of this study was to evaluate the ultrasound characteristics of the pelvic organs and the features of uterine blood flow in adolescents with abnormal uterine bleeding of puberty.

Material and methods
The study was carried out at the Department of Obstetrics, Gynecology and Pediatric Gynecology of Kharkiv National Medical University. The study involved examination of 93 adolescents with AUBP aged 11 to 18 years (mean age was 14.5 ± 3.5 years). Patients with AUBP were divided into 2 clinical groups: Group I consisted of 44 11-14-year-old patients, Group II of 49 15-17-yearold adolescents. Such a division into the groups was carried out due to the fact that, depending on the age of the patient with AUBP, there were marked clinical and laboratory manifestations associated with the menstrual age, duration and frequency of bleeding recurrence. The control group included 25 peers without menstrual dysfunction. The control group was not divided by age, since menstruating girls aged 13-14 and 15-17 years were not found to have significant differences in blood flow in the uterine and ovarian arteries, which is consistent with the literature [1,5].
The incidence of AUBP recurrence was 20.4% in Group I and 28.6% in Group II.
All the patients underwent a comprehensive clinical and laboratory examination. Ultrasound and Doppler study were performed using a Siemens ultrasound scanner (Germany) using a transabdominal transducer (3.5 MHz) and a transvaginal transducer (6.5-7 MHz) in sexually active adolescents.
Ultrasound examination of the pelvic organs assessed the state of the structure of the endo-and myometrium of the uterus, their relationship and uniformity. Identification of focal changes in the endometrium was accompanied with the description of their sizes. Moreover, ovarian sizes were determined and follicular apparatus was evaluated [7,8].
Characterization of the state of blood flow in the uterine and spiral arteries was carried out using a Doppler study at the time of examination of patients in the hospital. The study in patients of the control group was carried out in the first phase of the menstrual cycle on the 5th-7th day from the beginning of menstruation.
The uterine artery was visualized in the longitudinal plane at the level of transition of the cervix into the body. First, a longitudinal image of the cervix was obtained, and then the sensor was displaced to the lateral side until the vascular bundle of the uterus began to be clearly visualized at the level of the supravaginal part of the cervix.
The spectrum of blood flow velocity curves on the medial side from the bifurcation of the common iliac artery, typical for the vasculature with low resistance, was recorded in the form of a two-phase curve with low pulsation and high diastolic velocities [7]. Blood flow in spiral arteries was recorded in the area of their anatomical projection, in close proximity to the basal lamina of the endometrium [4].
When conducting a Doppler study, vascular resistance indices in both uterine and spiral arteries, resistance index (IR), pulsation index (PI), systolic-diastolic ratio (S/D) were calculated.
Statistical processing was performed using the Statistica for Windows version 6.1 general-purpose data processing software package.
Prior to the study, the protocol was presented at a meeting of the Ethics Committee of Kharkiv National Medical University. The study was started after approval of the protocol. According to the recommendations, the patients and their parents were informed about the purpose of the study, research methods, potential benefits and risks, as well as possible discomfort during the diagnosis. It was also explained that the decision on the participation or non-participation of the patient in this study at any stage of its implementation would not affect further management of the patient.

Results and their discussion
Ultrasound scan of the pelvic organs showed that the sizes of the uterus and ovaries in Groups I and II patients significantly exceeded the age parameters of girls in the control group ( Table  1). Most of the examined patients of both groups were found to have endometrial hyperplasia. The endometrium in adolescent girls with AUBP was characterized by a heterogeneous echostructure. In 29 (65.9%) adolescent girls of both groups, multiple hypo-and anechogenic inclusions were visualized secondary to heterogeneous structure of the endometrium.
Ovarian ultrasound revealed a multifollicular structure of the ovaries in 65% of patients in both groups. Retention formations of the ovaries were determined in 20% of Group I and in 35% of Group II patients (p <0.05). Table 1 presents the average size of the ovaries (right and left) in patients of the clinical groups.
Blood supply to the endometrium is known to be carried out by branches of the uterine arteries [6,7]. Radial arteries pass through the myometrium, and are then formed in the direct and spiral branches near the uterine cavity. Direct branches, which are called basal arteries, directly supply the basal layer of the endometrium. It is these vessels that supply the endometrium with blood. The function of the spiral arteries is the nutrition of the functional layer of the endometrium [2].
For a more accurate assessment of uterine hemodynamics and to avoid diagnostic errors, a Doppler study was performed in both uterine arteries [6]. Since the digital data of blood flow in the uterine arteries on the left and on the right did not have significant statistical differences, we presented the averaged parameters of this measurement (Table 2).
Ultrasound characteristics of the pelvic organs of patients with abnormal uterine bleeding of puberty Dopplerometric characterization of patients with abnormal uterine bleeding of puberty Note: * -significance of differences compared with the control group, p <0.05.
Note: * -significance of differences compared with the control group, p <0.05.