Prelying of a placenta
Prelying of a placenta – the anomaly of the period of pregnancy which is characterized by a placenta attachment to the lower segment of a uterus with partial or full overlapping of an internal uterine pharynx. Clinically prelying of a placenta is shown by the repeating bleedings from a genital tract, anemia of the pregnant woman, threat of an abortion, fruit and placentary insufficiency. Prelying of a placenta is diagnosed when carrying out a vaginal research, ultrasonography. Identification of prelying of a placenta demands prevention of spontaneous termination of pregnancy, correction of anemia and a hypoxia of a fruit, the choice of optimum tactics of a rodorazresheniye (is more often – Cesarean section).
Prelying of a placenta
The placenta (afterbirth, afterbirth) is important embryonic structure, skintight to an internal wall of a uterus and mother providing contact between organisms and a fruit. In the course of pregnancy the placenta carries out the nutritious, gas exchange, protective, immune, hormonal functions necessary for full embryo and fetus development. Physiological it is considered to be a placenta arrangement in the field of back and sidewalls of a body or a bottom of a uterus, i.e. in zones of the best vaskulyarization a miometriya. The placenta attachment to a back wall is optimum as protects this embryonic structure from casual damages. A placenta arrangement on the forward surface of a uterus meet seldom.
In case the placenta fastens so low that to some extent blocks itself an internal pharynx, speak about prelying of a placenta. In obstetrics and gynecology prelying of a placenta meets in 0,1-1% of all childbirth. At total closing with a placenta of an internal pharynx, there is an option of full prelying of a placenta. Such type of pathology meets in 20-30% cases from number of predlezhaniye. At partial overlapping of an internal pharynx the state is regarded as incomplete prelying of a placenta (frequency of 35-55%). At localization of bottom edge of a placenta in the III trimester at distance less than 5 cm from an internal pharynx are diagnosed a low arrangement of a placenta.
Prelying of a placenta creates conditions for prematurity and a hypoxia of a fruit, the wrong situation and prelying of a fruit, premature birth. The share of perinatal mortality when prelying a placenta reaches 7 - 25%, and maternal, caused by bleeding and hemorrhagic shock, - 3%.
Reasons of prelying of a placenta
Prelying of a placenta more often happens is caused by the pathological changes of endometrium breaking the course of detsidualny reaction of a stroma. Such changes can be caused by inflammations (tservitsita, endometritises), surgeries (a diagnostic scraping, surgical termination of pregnancy, a conservative miomektomiya, Caesarian the section, perforation of a uterus), the repeated complicated childbirth.
Endometriosis, myoma of a uterus, anomaly of a uterus (hypoplasia, dvurogost), polycarpous pregnancy, polyps of the tservikalny channel are ranked as number of etiologichesky factors of prelying of a placenta. Due to the called factors timeliness of implantation of fetal egg in the top departments of a cavity of a uterus is broken, and its attachment occurs in the lower segments. Prelying of a placenta develops at repeatedly pregnant more often (75%), than at primipara women.
Symptoms of prelying of a placenta
In clinic of prelying of a placenta as the leading manifestations serve repeated uterine bleedings of various degree of expressiveness. During pregnancy of bleeding, the placentae caused by prelying, are fixed at 34% of women, in the course of childbirth - at 66%. Bleeding can develop in different terms of pregnancy - from the I trimester before the childbirth, but a thicket – after the 30th week of a gestation. On the eve of childbirth in connection with periodic reductions of a uterus bleeding usually amplifies.
As the reason of bleedings serves the repeating otsloyka of the prelying part of a placenta arising in connection with inability of an afterbirth to stretch after a uterus wall at development of pregnancy or patrimonial activity. At an otsloyka there is a partial opening of interfleecy space that is followed by bleeding from uterus vessels. The fruit at the same time begins to test a hypoxia as the exfoliated site of a placenta ceases to participate in gas exchange. When prelying a placenta bleeding can be provoked by physical activity, cough, sexual intercourse, a natuzhivaniye at defecation, a vaginal research, thermal procedures (a hot bathroom, a sauna).
Intensity and the nature of bleeding are usually caused by extent of prelying of a placenta. Sudden development of bleeding, lack of pain, a blood loss profuseness is characteristic of full prelying of a placenta. In case of incomplete prelying of a placenta bleeding, as a rule, develops closer to the term of childbirth, is especially frequent – at the beginning of childbirth, during smoothing and disclosure of a pharynx. The more extent of prelying of a placenta, the earlier and more intensively happens bleeding. Thus, bleedings when prelying a placenta are characterized by external character, suddenness of the beginning without the visible external reasons (often at night), release of scarlet blood, painlessness, obligatory repetition.
Recidivous blood loss quickly leads to the pregnant woman's anemization. Reduction of OTsK and quantity of erythrocytes can become the reason of the DVS-syndrome and development of gipovolemichesky shock even in case of insignificant blood loss. The pregnancy complicated by prelying of a placenta often proceeds with threat of spontaneous abortion, arterial hypotonia, gestozy. The premature nature of childbirth takes place at full prelying of a placenta more often.
Placenta arrangement pathology affects in the most adverse way development of a fruit: causes fruit and placentary insufficiency, a hypoxia and a delay of maturing of a fruit. When prelying a placenta the pelvic, slanting or cross provision of a fruit is often observed. In the II-III trimesters of pregnancy localization of a placenta can change due to transformation of the lower uterine segment and change of growth of a placenta in the direction the miometriya is better than krovosnabzhayemy areas. This process in obstetrics is called as "migration of a placenta" and comes to the end by 34-35 week of pregnancy.
Diagnostics of prelying of a placenta
At recognition of prelying of a placenta existence of risk factors in the anamnesis at the pregnant woman, episodes of the repeating external uterine bleeding, data of an objective research is considered. At an external obstetric research the high standing of a bottom of a uterus caused by an arrangement of the prelying part of a fruit comes to light, it is frequent – cross or slanting provisions of a fruit. At an auskultation noise of placentary vessels is listened in the lower segment of a uterus, in the location of a placenta.
During the gynecologic research the uterus neck in mirrors for an exception of its injuries and pathology is examined. At the closed external pharynx the prelying part of a fruit cannot be established. At full prelying of a placenta the massive soft education occupying all arches of a vagina is palpatorno defined; at incomplete - forward or one of the side arches.
At passability of the tservikalny channel in case of full prelying the placenta closes all opening of an internal pharynx, and its palpation leads to strengthening of bleeding. If in a gleam of a uterine pharynx fetal covers and placentary fabric are found, incomplete prelying of a placenta is diagnosed. The vaginal research when prelying a placenta is carried out extremely carefully, in the conditions of readiness for rendering the emergency help at development of massive bleeding.
The safest objective method of identification of prelying of a placenta which is widely used by obstetrics and gynecology is ultrasonography. During an ekhografiya the option is established (incomplete, full) prelying of a placenta, the size, structure and the area of the prelying surface, degree of an otsloyka at bleeding, existence of retroplacentary hematomas, threat of termination of pregnancy, "migration of a placenta" in the course of the dynamic researches is defined.
Treatment when prelying a placenta
Tactics of conducting pregnancy when prelying a placenta is defined by expressiveness of bleeding and degree of blood loss. In the absence of bloody allocations the pregnant woman with prelying of a placenta can be in the I-II trimester under out-patient observation of the obstetrician-gynecologist. At the same time the guarding mode excluding the factors (physical activity, sex life, stressful situations etc.) provoking bleeding is recommended
On gestation term over 24 weeks or the begun bleeding observation of pregnancy is made in the conditions of an obstetric hospital. Medical tactics when prelying a placenta is directed to the maximum prolongation of pregnancy. The bed rest, medicines with a spazmolitichesky (drotaverin) is appointed and tokolitichesky (, ) action, carries out correction of iron deficiency anemia (iron medicines). For the purpose of improvement of a fetoplatsentarny and uterine and placentary blood-groove use introduction of a pentoksifillin, dipiridamol, ascorbic acid, a tiaminpirofosfat. At threat of the beginning of premature birth on the term from 28 to 36 weeks of pregnancy for prevention of repiratrny frustration at the newborn glucocorticoids (dexamethasone, Prednisolonum) are appointed.
As indications to the emergency early rodorazresheniye serve repeated bleedings over 200 ml, the expressed anemia and hypotonia, bleeding with one-stage blood loss from 250 ml, bleeding at full prelying of a placenta. Cesarean section in these cases is carried out for rescue of mother irrespective of the term of a gestation and viability of a fruit.
At successful prolongation of pregnancy to the term of 37-38 weeks the optimum method of a rodorazresheniye is chosen. Cesarean section is shown absolutely in all cases of full prelying of a placenta, and also at the incomplete prelying which is combined with the cross provision or pelvic prelying of a fruit; the burdened obstetric and gynecologic anamnesis; existence of a hem on a uterus, a mnogoplodiya, abundance of water, a narrow basin.
Natural childbirth is possible only at incomplete prelying of a placenta on condition of a maturity of a neck of a uterus, good patrimonial activity, head prelying of a fruit. At the same time continuous monitoring of a condition of a fruit and sokratitelny activity of a uterus (KTG, a fruit phonocardiography) is carried out. In early postnatal terms at women in labor atonichesky bleedings, a lokhiometra, the ascending infection and metrothrombophlebitis are quite often noted. At impossibility of a conservative stop of massive bleeding resort to to removal of a uterus: nadvlagalishchny amputation or a hysterectomy.
Prevention of prelying of a placenta
As measures of prevention of prelying of a placenta serve the prevention of abortions, early detection and treatment of genital pathology and hormonal dysfunction. At development of prelying of a placenta in the course of pregnancy early reliable diagnostics of anomaly, rational conducting pregnancy taking into account all risks, timely correction of the accompanying violations, an optimum rodorazresheniye is necessary.