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UDC 618.346-008.811.1-07
IDIOPATHIC POLYHYDRAMNIOS: RISK FACTORS AND SOME ASPECTS OF PATHOGENESIS
Altai State Medical University, Barnaul
M.B. Igitova, E.V. Megrelidze, I.V. Pyankova, I.V. Bogomolova
To measure the relative risk of the idiopathic polyhydramnios a retrospective analysis of the pregnancy course and the results of the urgent birth of 140 pregnant women with moderate polyhydramnios and 280 pregnant women with normal level of amniotic fluid has been performed. 70% of patients having polyhydramnios have shown risk factors of the infectious and inflammatory kind. The results of the histological analysis of the placenta have also shown the predominance of infectious genesis of the polyhydramnios. Key words: pregnancy, idiopathic polyhydramnios, risk factors.
The volume and composition of the amniotic fluid surrounding the fetus during intrauterine life are determined by the balance of production and resorption of amniotic fluid. In the second half of pregnancy, the main sources of amniotic fluid are the fetal urine and the secret of its lungs, suggesting a clear correlation between the volume of amniotic fluid and the functional state of the fetus [1, 2]. In 1984 P.F. Chamberlain et al. for the first time, revealed the relationship between increased amniotic fluid volume and adverse perinatal outcomes, as evidenced by recent studies [3, 4]. At present, somatic, infectious and immunological causes of the pathology of amniotic fluid volume are established, but idiopathic polyhydramnios remains an actual clinical problem requiring the allocation of managed risk factors for optimization of perinatal outcomes.
Objective: to identify risk factors for idiopathic polyhydramnios.
Materials and methods
A retrospective analysis of the course and outcome of 420 full-time pregnancies in the period from 2011 to 2016 (case-control study) was conducted using a targeted sample. The first group consisted of 140 women with moderate idiopathic polyhydramnios (in the analysis, cases of polyhy-dramnios were not included in the background of diabetes mellitus and immunological conflict in the Rh factor and the ABO system), the second group included 280 women with normal amniotic fluid. The analysis of clinical and anamnestic parameters, the features of the course and outcome of pregnancy for mothers and newborns, the data of ultrasound and clinical and laboratory examination, the results of histological examination of the afterbirth was carried out. Since the ultrasonic evaluation of the amniotic fluid index (AFI) is the clinical standard for the diagnosis of polyhy-dramnios, the volume of amniotic fluid was evaluated by ultrasound by Sone Scape SSi-6000, ALO-KA-SSD-2000, Sonoline-Elegra (Simens) by AFI, for which gestational norms were established [5, 6].
Statistical processing of the results was carried out using the computer program "Sigma Plot 11.0" for Windows. The results of the work are presented in the form of values M (arithmetic mean) ± a (mean square deviation). Evaluation of the reliability of the differences in quantitative indicators was carried out according to the Student t-tables criterion. The critical value of the level of statistical significance was assumed to be 0.05.
The assessment of risk factors for the formation of polyhydramnios was based on the analysis of more than 50 potential predictors and was conducted using the program MedCalc 9.1.0.1 for Windows [7] through four-field contingency tables, where one of the factors was the case of idiopathic polyhydramnios. The effect of each specific factor was assessed by the relative risk (Relative risk, RR). To demonstrate the relation strength, a 95% confidence interval (CI) for RR was calculated.
Results and discussion
The average age of the pregnant group was 27.4 ± 4.6 years, the second group was 26.5 ± 4.6 years (p = 0.278). Among the social factors, there was an increase in the number of unmarried women in the group of pregnant women with polyhy-dramnios: 39 patients, which is 27.8%, the comparison group included 52 pregnant women (18.6%, p = 0.042). Primigravidae were 53 women of the first group (37.9%) and 113 patients of the second group (40.4%, p = 0.698), 77 (55.0%) and 190 (67.9%) pregnant (p = 0.013). The anamnesis complicated by artificial abortions, was found in 47 patients of the first group (33.6%) and 109 women of the second group (38.9%, p = 0.331). Spontaneous abortions in the anamnesis were registered in women of comparison groups with the same frequency: in 24 (17.1%) women of the first group and in 53 (18.9%) women of the second group (p = 0.752). Thus, according to the age and peculiarities of the obstetrical anamnesis, the women of the comparison groups were comparable, but in our study, polyhydram-nios was more often observed in the multiparous women.
The peculiarity of the reproductive health of women with idiopathic polyhydramnios is the higher incidence of infectious and inflammatory diseases of the genitals in the anamnesis. Thus, nonspecific vaginitis before pregnancy occurred in 49 (35.0%) women of the first group (in the comparison group - in 69 patients, which is 24.6%, p = 0.034). The specific gravity of tumors and/or tumor formations of the ovaries in the anamnesis was identical (2.1% and 2.1%, p = 0.718), however, hormone-dependent diseases (uterine myoma, en-dometriosis) in the group of women with polyhy-dramnios were more significantly detected (8 , 6% and 2.5%, p = 0.0098).
The analysis of somatic complications showed an increase in the incidence of chronic infectious and inflammatory diseases of the kidneys and urinary tract in the group of women with polyhy-dramnios (21.4% and 11.8%, p = 0.014), whereas chronic infectious and inflammatory diseases of ENT organs and respiratory organs were observed with the same frequency (11.4% and 9.3%, p = 0.614). In addition, in the first group, pregravid obesity was registered 2 times more often (15.0% and 7.8%, p = 0.033) and 1.7 times more often -chronic arterial hypertension (12.9% and 7.1% p = 0.076). For the rest of the nosological groups, there was no statistically significant difference.
The course of the gestational process in both groups was associated with a high incidence of complications, but significant differences were established in the frequency of the threat of abortion (40.7% and 30.4%, p = 0.046) and anemia (25.0% and 16.1% , p = 0.039), whereas moderate preeclampsia was recorded with the same frequency (14.3% and 12.9%, p = 0.806).
In the group of women with polyhydramnios, 22 patients (15.7%) underwent acute somatic infectious-inflammatory diseases with hyperther-mia (including respiratory infections) during pregnancy, in the comparison group - 25 women, which is 8.9%, (p = 0,05). The frequency of detection of acute vaginitis during pregnancy was also higher in the first group of pregnant women (22.1% and 10.7%, p = 0.0029).
Hemodynamic disorders in the "mother-placenta-fetus" system were revealed in 24 (17.1%) women of the first group and 42 (15.0%) in the second group of pregnant women (p = 0.678) according to the results of dopplerometry. The average AFI by full term pregnancy in the first group of women was regularly higher and amounted to 240.0 ± 35.5 mm, in the second group - 154.9 ± 33.1 mm (p <0.0001).
Despite the absence of differences in the frequency of detection of placental dysfunction, perinatal outcomes in the first group of women were significantly worse than in the comparison group. Various diseases were detected in 63 (45.0%) children from mothers with polyhydramnios, while
in the second group, 75.0% of the newborns were healthy (p = 0.0001). The risk of neonatal complications with maternal idiopathic polyhydramnios increased significantly (RR = 1.77, 95% CI 1.362.29, p <0.0001). Among the nosological forms in neonates, prevailed cerebral ischemia (23.6% in the first group and 14.6% in the second group, p = 0.0318) and conjunctival jaundice (7.1% and 3.6%, p = 0.179). Thus, the hypoxic-ischemic lesion of the central nervous system was the dominant nosological form determining neonatal morbidity in the children of the group under analysis. The in-trauterine growth delay in the hypotrophic type in the compared groups of newborns was recorded with the same frequency (5.0% and 7.1%, p = 0.537) and did not exceed the population index.
Based on the obtained data, it can be assumed that a number of anamnestic factors, somatic diseases and complications of gestation affect the risk of formation of idiopathic polyhydram-nios. The risk of this complication increased by miscarriages (RR = 1.43, 95% CI 1.09-1.86, p = 0.009), and in unmarried women (RR 1.4, 95% CI 1.05-1 , 86, p = 0.023). Analysis of the medical history revealed that the risk increased significantly if a patient had chronic infectious inflammatory diseases of the kidneys and urinary tract (RR = 1.55, 95% CI 1.14-2.09, p = 0.0047). Two non-infectious risk factors were also identified: pregravid obesity (RR = 1.55, 95% CI 1.10-2.17, p = 0.012) and chronic hypertension (RR = 1.48, 95% CI, 1.03- 2.13, p = 0.035). In the gynecological history block, the risk of idiopathic polyhydramnios was significantly associated with hormonal-dependent processes (RR = 1.98, 95% CI 1.36-2.87, p = 0.0003), and acute infectious-inflammatory diseases of the genitals (RR = 1.38, 95% CI 1.05-1.81, p = 0.022). A significant complication was established by vaginitis during pregnancy (RR = 1.67, 95% CI 1.25-2.24, p = 0.0006) and with acute somatic infectious-inflammatory disease with hyperthermia during gestation (RR = 1.48, 95% CI 1.05-2.8, p = 0.023).
Thus, the study allowed to identify a number of risk factors for idiopathic polyhydramnios, the most frequent of which are infectious-inflammatory diseases that were observed both before the onset of pregnancy and during its course: chronic somatic foci of bacterial infection, infectious and inflammatory diseases of the genitals in the anamnesis, acute somatic infectious-inflammatory diseases and vaginitis during gestation. In general, the risk factors for infectious and inflammatory diseases occurred in 70% of pregnant women with idiopathic polyhydramnios. It can be assumed that the presence of acute or chronic foci of infection in pregnant women of the first group determined not only the development of polyhydramnios, but also an increase in the frequency of complications such as the threat of abortion and anemia. To confirm this assumption, an evaluation of the inflam-
matory response in a full-term pregnancy was made based on the parameters of a clinical blood test performed as part of a standard clinical and laboratory examination, and the results of a histological study of the afterbirth were analyzed (98 cases in the first group and 208 in the second group).
According to the literature, a more informative index of the inflammatory response in comparison with the determination of the total number of leukocytes in the peripheral blood is the calculation of the absolute number of neutrophilic leukocytes [8]. In pregnant women of the first group, the absolute number of neutrophilic leukocytes ranged from 4.3 to 11.9 x 109/L, the mean value was 7.55 ± 1.99 x 109/L. In pregnant women of the second group, the absolute number of neutrophilic leukocytes was in the range from 4.4 to 10.2 x 109/L, the mean value was significantly lower and amounted to 6.79 ± 1.45 x 109/L (p = 0.048).
Results of a standard histological study of the afterbirth revealed inflammatory changes in the placenta and amniotic membranes, represented by hematogenous infection (deciduit, in-tervillusitis) and ascending infection (choroid de-ciditis, chorioamnionitis and funiculitis) in women of both groups. By detecting inflammatory changes in the afterbirth, the pathways and stages of infection were assessed in accordance with the level of lesion [9].
The specific weight of inflammatory changes in the placenta and amniotic membranes in women with polyhydramnios was higher than in the comparison group, they were detected in 43 patients of the first group (43.9.8%) and in 63 women of the second group (30.3%, p = 0.0275). In patients of the first group, hematogenous infection path prevailed, which was registered 1.8 times more often than in the comparison group (in 31 cases, that is 31.6%, in the second group - 17.5%, p = 0.0086). The frequency of detection of the first stage of the disease (deciduitis) was comparable: in 21 patients of the first group (21.4%) and in 56 women of the second group (26.9%, p = 0.372). At the same time, the second and third stages of the lesion (chorio-deciduit, chorioamnionitis, combination of deciduit with chorioamnionitis or funiculitis) in women with polyhydramnios were significantly more frequent: in 16 women, which is 16.3% (in the comparison group - in 7 patients, 3.4%, p = 0.0002). It should be noted that the most severe inflammatory changes (funiculitis, umbilical phlebitis) were detected only in the group of women with polyhydramnios (three cases, which is 3.1%, p = 0.053). Thus, the results of a histological study of the afterbirth indicate a predominance of the infectious-inflammatory genesis of polyhydramnios, which is clinically regarded as idiopathic.
Conclusions:
1. In 70% of pregnant women with idiopathic polyhydramnios, risk factors of an infectious-inflammatory nature are revealed. Infectious and inflammatory diseases that significantly increase the risk include chronic somatic foci of bacterial infection, infectious and inflammatory diseases of the genitals in the anamnesis, acute somatic infectious, inflammatory diseases and vaginitis during gestation.
2. Pregnant women with polyhydramnios are more likely to have inflammatory changes in the afterbirth, indicating both hematogenous and upward infection.
3. Predictors of polyhydramnios of infectious and inflammatory character are "relatively" manageable at the pre-gravid stage and during gestation, so full pre-conceptual preparation and rational antenatal monitoring (sanation of foci of infection) may allow optimizing the course of pregnancy and improving perinatal outcomes.
References
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Contacts
Corresponding author: Igritova Marina Borisovna, Doctor of Medical Sciences, Professor of the Department of obstetrics and gynecology with the course of FVE, Altai State Medical University, Barnaul. 656044, Barnaul, ul. Popova, 29. Tel.: (3852) 441917. Email: igitova-2011@mail.ru
Megrelidze Elena Viktorovna, Candidate of Medical Sciences, Associate Professor of the Department of obstetrics and gynecology with the course of FVE, Altai State Medical University, Barnaul. 656044, Barnaul, ul. Popova, 29. Tel.: (3852) 542360. Email: science@agmu.ru
Pyankova irina Vladimirovna, Assistant of the Department of obstetrics and gynecology with the course of FVE, Altai State Medical University, Barnaul.
656044, Barnaul, ul. Popova, 29. Tel.: (3852) 542360. Email: science@agmu.ru
Bogomolova Irina Valeryevna, resident physician of the Department of obstetrics and gynecology with the course of FVE, Altai State Medical University, Barnaul.
656044, Barnaul, ul. Popova, 29. Tel.: (3852) 542360. Email: science@agmu.ru
