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UDC 618.29:616-053.31-005.4
OBSTETRICAL ASPECTS OF FORMATION OF HYPOXIC-ISCHEMIC CNS DISORDERS IN FULL-TERM LOW-WEIGHT NEWBORNS
1 Altai State Medical University, Barnaul
2 FSBHI "Maternity Hospital No.2", Barnaul
N.S. Dolgova12, S.D. Yavorskaya12, L.P. Ananyina2, Ye.V. Pozhenko2
There was carried the retrospective analysis of case records of 100 full-term newborns with diagnosed fetal growth retardation. In order to estimate the predictors of hypoxic-ischemic encephalopathy in newborns there were formed two groups of comparison: newborns without perinatal disorders of CNS (n=49) and with moderate and severe perinatal disorders of CNS (n=51). The comparative analysis was conducted by 125 criteria. It was stated, that prognostically unfavorable factors for the health of newborns are: mother's excessive weight before the period of gestation (21,5±0,5 and 23,8±0,7; f=0,011) and thrombocytopenia shortly before delivery (33,3% and 94,1 %; f=0,011). Pregnant women with markers of placental dysfunction according to the results of Doppler velocimetry (53,1% and 76,5%; р=0,025) in the third trimester of pregnancy constitute the risk group of not only FGR, but also of perinatal CNS disorders.
Kew words: low birth-weight fetus, fetal growth retardation, newborns, pregnancy, perinatal CNS disorders.
Introduction
The birth of a healthy child is an invaluable gift that nature gives us free of charge. According to the Federal State Statistics Service, over the past 25 years, infant mortality has declined by 2.4 times (from 17.4 per 1000 live births in 1990 to 7.4 in 2014), but, despite the positive dynamics, this indicator remains 2-3 times higher than in many European countries [1]. It is known that the health of the fetus and the newborn depends largely on the mother's maternal and reproductive health, the course of pregnancy and childbirth [2].
One of the serious complications of gestation is the intrauterine growth restriction (IGR). This complication increases the risk of perinatal mortality by 6-10 times in comparison with newborns born with normal body weight. Children with IGR are at high risk for disorders of neurological and physical development, metabolic syndrome in adulthood, type 2 diabetes, coronary heart disease and hypertension [4, 5, 6, 7, 8]. Obstetricians and neonatologists are well aware that children born with a low body weight present a different contingent of patients. Some newborns are diagno-zed with perinatal pathology, while others do not have functional disorders of the central nervous system and are let home from the maternity hospital [9].
Research objective
To establish anamnestic and gestational features of mothers who gave birth to full-term babies with perinatal CNS disorders.
Materials and methods
There was performed a retrospective analysis of 100 delivery records of pregnant women, 100 birth histories and 100 records of newborns born
at the term of 370/7-416/7 weeks, who had been diagnosed with IGR at birth.
Inclusion criteria: full-term pregnancy, newborn with an IGR, urgent birth with one fetus, parents of a European race.
Exclusion criteria: premature birth, twins, parents of non-European race.
The gestation period at the time of delivery was established by the date of the last menstruation and data of the ultrasound investigation of the fetal egg in the period of 11-14 weeks [10]. The diagnosis of IGR was established after evaluating the physical development of the newborn according to the table of G.M. Dementyeva, taking into account the gestational term [11].
In the course of study, all newborns were divided into 2 comparison groups: the first group consisted of 49 newborns without significant CNS disorders (were let home), the second group - 51 newborns, with perinatal CNS disorders of medium and severe degree, who needed the second stage of nursing. To establish the predictors of combined perinatal pathology, a comparative analysis was carried out on 125 criteria, which were ranked by groups, taking into account the mother's anam-nestic data, the features of the course of pregnancy and childbirth.
Statistical processing of the obtained data was carried out on a personal computer using the Statistica 10.0 and Excel 2007 applications. Different methods of statistical processing were used in the work, depending on the type of random variables and the task of the study [12]. To estimate the normality of the distribution of characteristics, the kurtosis and asymmetry indicators characterizing the shape of the distribution curve were used.
The values of the continuous quantities are given in the form M ± m, where M is the sample
mean and m is the standard error of the mean. The values of qualitative characteristics are presented in the form of observed frequencies and percentages. In cases of normal distribution, as well as the equality of variances, Student's t-test was used to compare the averages. The dispersion equation was estimated by the F-criterion. In the case of distributions that do not correspond to the normal law, as well as for variance inequality, the nonpara-metric Mann-Whitney U-test was used.
To compare the qualitative characteristics, a nonparametric x2 criterion was used. In the presence of low frequencies (less than 10), the Yates correction for continuity was used for this criterion. By frequencies less than 5, Fisher's four-field conju-gacy tables were used. The critical level of statistical significance for testing the null hypothesis was assumed to be 0.05. In all cases, bilateral criteria were used.
Results and discussion
The average age of mothers (26.6 ± 0.8 and 27.7 ± 0.8, p = 0.3) did not vary in the groups. There were no differences in the evaluation of data from social and obstetrical gynecological history of mothers of two comparison groups. Such important for the formation of placental dysfunction and IGR as a maternal illness, such as hypertension syndrome (10.2% and 7.8%, p = 0.95), violation of carbohydrate metabolism (6.1% and 7.8%, p = 0.956) and thyroid function (18.4% and 25.5%, p = 0.537), diseases of the urinary system (30.6% and 51%, p = 0.062), also did not significantly differ in the comparison groups. When assessing anthropometric data, it was found that for the same average growth rates of mothers of comparison groups (162.7 ± 0.9 and 162.8 ± 0.8, p = 0.9), the mass-growth ratio was different. Mothers who gave birth to children with a lower health index entered into a pregnancy with a greater body weight (56.8 ± 1.3 and 63.1 ± 2.1, p = 0.012), they initially had a higher body mass index (21.5 ± 0.5 and 23.8 ± 0,7, p = 0.011), which can speak of the available hidden violation of carbohydrate-fat metabolism. A number of authors believe that overweight is a risk factor for an unfavorable outcome of pregnancy [13]. Mothers of children of the second comparison group were significantly more likely to have overweight before pregnancy (14.3% and 37.3%, p = 0.017).
The assessment of the course of pregnancy in patients of the two groups of comparison revealed that in most of the women it was complicated. In the first trimester of pregnancy, each tenth patient of two comparison groups (10.2% and 9.8%, p = 0.79) had clinical and paraclinic signs of threatened miscarriage, one out of five had early toxicosis requiring in-patient treatment (20.4% and 19.6%, p = 0.881). Acute respiratory viral infections in the early stages of pregnancy were carried by every fourth patient of the first and every fifth
of the second comparison groups (26.5% and 19.6%, p = 0.559). All this could have a negative effect on the formation of the placental complex and subsequently cause its dysfunction. The second trimester of pregnancy proceeded against the threat of termination of pregnancy in 31% of cases, without significant differences in comparison groups (30.6% and 31.4%, p = 0.893), but vulvovaginitis of non-specific etiology was significantly more common in the group of mothers who gave birth to children with low body weight without perinatal CNS injuries (38.8% and 17.6%, p = 0.033). Mothers of children of comparison groups had acute respiratory viral diseases in the second trimester of pregnancy with practically the same frequency (20.4 and 17.6%, p = 0.923). Ultrasonic markers of IGR in the second trimester of pregnancy were diagnosed in 2% of cases, in comparison groups with the same frequency.
Significant gestational complications of third trimester pregnancy, edema due to pregnancy (20.4% and 23.5%, p = 0.892), the threat of premature birth (16.3% and 19.6%, p = 0.868), preeclampsia (4, 1% and 15.7%, p = 0.11) in the comparison groups did not significantly differ. Interesting data were obtained by studying the hematologi-cal indices of red blood of mothers who gave birth to low-weight children. So, with statistically insignificant differences in the mean level of leukocytes, erythrocytes and hemoglobin, the average platelet count in the third trimester of pregnancy was lower in the group of mothers who gave birth to children with perinatal CNS disorders (247.2 ± 64.6 and 135.3 ± 4.4 ; p = 0.006). Thrombocytopenia of mild severity preceding labor in this group was detected 3 times more often (33.3% and 94.1%, p = 0.011). Perhaps this is due to the fact that some mothers of newborns of the second group received low molecular weight heparins during pregnancy in order to correct progressive placental dysfunction. The diagnosis of delayed fetal development during pregnancy is more often established in mothers who gave birth to children with perinatal CNS disorders (32.7% and 43.1%, p = 0.382), which was the reason for prenatal hospitalization. By the assessment of the condition of the placen-tal complex before the delivery, signs of premature aging of the placenta, in particular calcints, are more often detected in pregnant women who gave birth without a perinatal complication from the CNS (65.3% and 45.1%, p = 0.057), which may indirectly indicate their higher readiness for extra-uterine life. According to the Dopplerometry data, disorders of the uteroplacental blood flow are significantly more often established, on the contrary, in the pregnant women of the second group (53.1% and 76.5%, p = 0.025). The method of delivery in the compared groups was identical, the frequency of operative labor was high (49.0% and 49.0%, p = 0.845).
In most cases, the newborns of the comparison groups were born without signs of asphyxia, with an Apgar score of 8-10 points (91.8% and 88.2%, p = 0.790). However, in the future, each tenth newborn of the second comparison group had respiratory disorders (0% and 11.8%, p = 0.04). In the same group of newborns, signs of morpho-functional immaturity were diagnosed twice (4.1% and 7.8%, p = 0.711). After the anthropometric data were evaluated, all the newborns in the comparison group were diagnosed with IGR, but the newborns of the first comparison group exceeded all new-borns of the second group in all anthropometric criteria: mean weight (2558.4 ± 26.2 and 2423.4 ± 32.1, p = 0.002), average height (49 ± 0,2 and 47,7 ± 0,2, p = 0,001), head circumference (32,1 ± 0,2 and 31,5 ± 0,2, p = 0,023), chest circumference 31.3 ± 0.2 and 30.2 ± 0.3, p = 0.003), indicating a later development of placental dysfunction in this group. The majority of newborns had a hypotrophic type of IGR, significantly more often in the first group (87.8% and 70.6%, p = 0.063), usually in the form of hypotrophy of I degree (77.6% and 54.9%, p = 0.029). Hypoplastic variant of IGR, on the contrary, was registered 2.4 times more often in newborns of the second group (12.2% and 29.4%, p = 0.063).
During the adaptation period (the first 3 days of life), only 8.2% of the newborns of the first comparison group had clinical signs of perinatal CNS disorders of the first comparison group; all new-borns of the second comparison group had moderate or severe CNS perinatal disorders (p = 0.001). The most frequent clinical manifestations of perinatal CNS disorders were muscular hypotension (6.1% and 29.4%, p = 0.006), neuro-reflex excitation (2% and 21.6%, p = 0.007) and cerebral ischemia, which occurred only in three newborns of the second group (0% and 5.9%, p = 0.255). By the neuro-sonoscopy, subependimal cysts significantly more occurred in the newborns of the second group (2% and 15.7%, p = 0.042).
Thus, full-term low-weight newborns present different contingents not only in terms of severity and type of hypotrophy, but also in the initial state of the central nervous system. Considering that the degree of hypotrophy in full-term newborns is usually not highly expressed (late realization of placental dysfunction), they have a high frequency of late and unsatisfactory diagnosis of the intra-uterine state of the fetus, post-factum diagnosis, which in the number of fetuses leads to marked changes in the central nervous system of hypox-ic-ischemic origin. Prognostically unfavorable factors for the health of newborns are: the increased weight of the mother before the gestation period and thrombocytopenia preceding the childbirth. Pregnant women with the presence of markers of placental dysfunction according to Doppler-ometry data, in the third trimester of pregnanc, are a risk group not only for IGR, but for perinatal
CNS disorders. All full-term newborns born with low body weight require complex early diagnosis of markers of hypoxic-ischemic encephalopathy.
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Contacts
Corresponding author: Dolgova Nadezhda Serge-yevna - post-graduate student of the Department of obstetrics and gynecology with the course of FVE of ASMU, Barnaul. Tel.: (3852) 36-85-87. E-mail: author-dolgovans@yandex.ru
