Anomalies and Diseases of the Placenta Membranes and Umbilical Cord

Anomalies and Diseases of Membranes. Hydramnion (polyhydramnios) — a pathological condition characterized by excessive accumulation of amniotic fluid (more than 1.5 l) in аmniotic cavity. Hydramnion is a disease of chorion, at which a secretory and resorption function of the placenta is disturbed.

Acute (fast formation up to 3 litres of fluid and over) and chronic (a gradual increase of quantity of amniotic fluid) hydramnion are distinguished. Etiology of polyhydramnios is not found out. It is known that the development of polyhydramnios can result from:
- extragenital diseases during pregnancy (diabetes mellitus, pyelonephritis, diseases of
- cardiovascular system, infection);
- Rh-incompatibility in pregnancy;
- multiple pregnancy;
- congenital abnormalities of the fetus.

Clinical features of acute hydramnion: painful feeling in the stomach, dyspnea, dysfunction of cardiac activity, general malaise. It is frequently accompanied by premature development of labor pains; the pregnancy is interrupted before the term. At chronic hydramnion the accumulation of waters occurs slowly, the pregnant does not feel changes, adapts for increase of quantity of amniotic fluids. Abnormalities of fetal condition, development of fetus, prematurity are frequent complications in such cases.

Diagnostics is based on the following data:
- examination (a round shape of the uterus, "frog" abdomen);
- measurement of abdomen size (size of uterus is larger than expected at a given term of pregnancy);
- palpation of the fetus is complicated, the symptom of fluctuation is positive;
- the pregnant marks an increased mobility of the fetus in uterus; it can be accompanied with unstable fetal lying;
- auscultation of fetal heart sound is laboured.

The diagnosis is confirmed to ultrasonic examination.

Oligohydramnios — the quantity of amniotic fluid is less than 0.5 l. A complete absence of amniotic fluid is called by the term anhydramnios. Primary (idiopathic) and secondary oligohydramnios are distinguished.

Primary oligohydramnios develops due to a primary damage of epithelium of amniotic membrane. It is considered that insufficiently developed epithelium, lining amniotic membrane, does not produce enough amniotic fluid. In some cases oligohydramnios develops as a result of increased resorption of waters by membranes. The reasons remain unknown. Oligohydramnios results in disturbed intrauterine development of the fetus: the deformations of bones, curvature of vertebral column and extremeties, talipes are observed. A sharply curved vertebral column with the head thrown backwards is characteristic.

Because of small quantity of amniotic fluid the fetal movements in uterine cavity are limited and laboured. The fusion of skin of the fetus with amnion, formation of amniotic adhesions, i.e. strong strings and bands bringing to аtrophy and even to amputation of extremities are possible.

Clinical features of oligohydramnios: the pregnant women feel pains in the abdomen amplified at movements of the fetus. Abdominal circumference is less than expected at a given term of pregnancy. Spontaneous abortion or premature delivery is frequent complications in pregnancy with oligohydramnios; labor pains in patient with oligohydramnion are very painful, noneffective. Bleedings in postpartum period are often. The incidence of intrauterine death of the fetus is very high.

Treatment: pathogenetic principles of treatment are not found yet. On establishing the diagnosis of oligohydramnios, the management of pregnant depends on concrete obstetric situation, symptomatic therapy should be administered.

Secondary (traumatic) oligohydramnios (hydrorrhea gravidarum) is a disease, at which during a long period of time the outflow of amniotic fluid occurs in connection with a high rupture of amniotic membranes. Amniotic fluid flows out in small quantity, because the tears between membranes and uterus is small and little liquid passes. Usually pregnancy nevertheless is interrupted because of penetration of infection into the uterine cavity, or because of development of regular contractions of uterine musculature.

On establishing the diagnosis of amniotic hydrorrhea, a strict bed regimen, spasmolytic and tocolytic drugs, аntibacterial therapy for prevention of ascending infection are administered. The treatment for improvement of metabolic processes in placenta, improvement of uterine-placental circulation, symptomatic therapy are carried out. Depending on term of pregnancy, a therapy aimed at acceleration of development of surfactant system of the fetal lungs should be administered. A similar conservative treatment of amniotic hydrorrhea is carried out under the strict control of blood indexes (leucocytes, erythrocyte sedimentation rate), vaginal discharges.

On occurrence of increase of leucocyte number, or erythrocyte sedimentation rate, other signs of infection, pregnancy is interrupted by medical indication. The method of interruption depends on obstetric situation and term of pregnancy.

Anomalies of Umbilical Cord. The anomalies of umbilical cord include anomalies of development of the cord vessels (presence of the third artery, two separate vascular fascicles, atypical anastomoses, aneurisms, arterial nodes), anomaly of the umbilical cord length (excessively long, excessively short), formation of true and false knots of umbilical cord, etc.

A long umbilical cord — the length of cord reaches 70 cm and over. An excessively long umbilical cord is dangerous because at movements of intrauterine fetus the winding of the cord round the fetal neck, trunk, extremities can take place. The winding of the cord may be single and multiple, tight and not tight. If the winding is not tight and there is no excessive tension of umbilical cord during labor, delivery of the fetus may happen without complications. A tight winding of umbilical cord may lead to asphyxia of the fetus, premature separation of normally implanted placenta during labor. An excessively long umbilical cord is also dangerous due to the fact that at fast discharge of amniotic fluid and mobile head of the fetus there can be a loss of loops of umbilical cord, that entails аsphyxia of the fetus and requires urgent operative intervention in labor.

A short umbilical cord — the length of umbilical cord is less than 50 cm. Shortening of umbilical cord can be relative and absolute. An absolutely short umbilical cord means that its length is less than 40 cm. The umbilical cord of normal length (or longer than ordinary), shortened due to winding round the neck or trunk of the fetus is a relatively short umbilical cord.

An excessively short umbilical cord complicates movements of the fetus and can be the reason of malposition of the fetus in the uterus (transverse or oblique lying of the fetus), breech presentation. In the second stage of labor a short umbilical cord, stretching, results in delay of passing of the fetus through the labor canal, аsphyxia of the fetus, preterm separation of placenta.

The true knots of umbilical cord form in early terms of pregnancy, when still a small fetus slips through a loop of umbilical cord during intrauterine movements. If the knot is tightened, the fetus dies from аsphyxia; it can take place during pregnancy and in labor. If the knot is not tightened, the fetus is born alive.

False sites of umbilical cord are limited thickenings on umbilical cord representing varicose sites of its vessels or local congestions of Wharton jelly. They are of no pathological value.

Anomalies of attachment of umbilical cord to the placenta — normally the attachment of umbilical cord to the placenta takes place in the central or lateral area. Sometimes the umbilical cord is attached to the membranes of the placenta. Thus the vessels go to placenta between the amnionic and chorionic membranes. If this site of membranes is located in the lower uterine segment, it can be ruptured during labor, thus from the broken umbilical vessels the bleeding, dangerous to life of the fetus, begins.

The rupture of umbilical cord is observed extremely seldom. It can occur in precipitated labor, at some obstetric manipulations, if umbilical cord is short. The contributing factors are varicose change, insufficient development of elastic fibres.