Polyhydramnios in pregnant women in late terms: ultrasound signs, management of labor

Hydramnion is a condition characterized by excessive accumulation of amniotic fluid in the amniotic cavity. With polyhydramnios, the amount of amniotic fluid exceeds 1.5 liters and can reach 2-5 liters, and sometimes 10-12 liters and more. According to different authors, this pathology is found in 0.6-1.7% of pregnant women.

[1], [2], [3], [4], [5]

Causes of polyhydramnios

Pathological conditions of pregnancy, in which there may be polyhydramnios:

• diabetes;
• acute or chronic infections, in particular TORCH infections;
• inflammatory processes of female genital organs;
• multiple pregnancies;
• isoserological incompatibility of blood of mother and fetus, more often by Rh-factor;
• gestosis;
• diseases of the cardiovascular system;
• anemia;
• hemoglobinopathy (α-thalassemia);
• fetal development anomalies;
• pathology of the placenta (chorionioma).

Among the causes of polyhydramnios, one of the leading places is diabetes mellitus - 25%.

The immediate etiological factor of polyhydramnios is also an infection. It is proved that signs of inflammation of placental tissues and fetal membranes are present in 50% of cases of polyhydramnios.

The frequency of congenital malformations of the fetus during polyhydramnios, according to the data of different authors, fluctuates in fairly wide chapters and is at least 20%.

The most common congenital malformations of the central nervous system (anencephaly, hydrocephalus, microcephaly, spina bifida, etc.) and digestive tract (atresia of the esophagus, atresia of the duodenum, large intestine, Hirschsprung's disease, Meckel's diverticulum, diaphragmatic hernia, omphalocele, gastroschisis and other).

It is known that the following mechanisms underlie the development of polyhydramnios:

• hyperproduction of amniotic epithelium of amniotic fluid components and delay in their excretion (TORCH-infection, inflammatory processes of female genital organs);
• excessive transudation through fetal vessels, which is observed in a fetus-recipient with a transfusion syndrome in case of multiple pregnancy or with a common hemangioma of the placenta;
• violation or absence of the mechanism of swallowing amniotic fluid by the fetus as one of the mechanisms regulating their quantity (congenital malformations of the digestive tract of the fetus);
• additional transudation of fluid through large skin defects of the fetus (ulcer teratoma and other malformations of the fetus).

[6], [7], [8], [9]

Symptoms of polyhydramnios

There are acute and chronic polyhydramnios. Chronic polyhydramnios develop gradually and pregnant, as a rule, adapts to this condition. Acute polyhydramnios are extremely rare, develop rapidly, complaints are more pronounced, sometimes observed with monozygotic double and much more often - with infectious diseases (especially viral) and fetal malformations, usually in 16-24 weeks.

Comparative characteristics of acute and chronic polyhydramnios

Acute polyhydramnios	Chronic polyhydramnios
Occurs very rarely	Occurs often
Rapid fluid accumulation	Accumulation of fluid occurs gradually
Detectable before the 20th week	It is found in later terms of gestation
Fruit anomalies are detected in 100% of cases	Fetal developmental defects are not always detected

On the part of the mother with polyhydramnios, complaints can arise about moderate increase in the size of the uterus, increased motor activity of the fetus, shortness of breath, abdominal discomfort, pain (with acute polyhydramnios). In late terms with polyhydramnios, there may be signs of a threat of abortion, premature birth.

The height of the standing of the bottom of the uterus and the circumference of the abdomen are significantly higher than those of the expected duration of pregnancy. The uterus is strained, of a tauto-elastic consistency, when it is palpated, a fluctuation is determined. Fetal parts are difficult to prolactate, when palpation the fetus easily changes its position, the presenting part is located high above the entrance to the small pelvis, the heart tones of the fetus are muffled, poorly tapped. Excessive motor activity of the fetus can be observed. In labor during vaginal examination, an intense fetal bladder is determined, regardless of the fights.

Effects

Possible complications of pregnancy:

• vomiting (in 36% of pregnant women);
• threat of abortion and premature birth;
• late spontaneous abortion, premature birth (7.3%);
• incorrect position of the fetus (6.5%);
• distress of the fetus;
• syndrome of intrauterine growth retardation;
• late gestosis (5-20%);
• premature discharge of amniotic fluid.

[10], [11], [12], [13], [14], [15], [16], [17]

Diagnosis of polyhydramnios

In addition to carefully studying the complaints of a pregnant woman, conducting an external obstetric study to detect polyhydramnios, the performance of ultrasound is very important.

Currently, there are 2 main methods for measuring the amount of amniotic fluid in ultrasound:

• the definition of the index of amniotic fluid (AND AJ) is the "gold standard". To determine the IOL, the uterine cavity must be conditionally divided into four quadrants. Then in each quadrant the depth of the largest pocket of the amniotic fluid, free from the parts of the fetus, is determined. The sum of the four values represents the IAD. The diagnosis of malnutrition is praised in those cases when the IWA is below 5%. Polyhydramnios are characterized by an increase in IAB values of more than 97.5%.

• Determination of the size of the largest pocket of fluid, free from small parts of the fetus and the umbilical cord, which is measured in two mutually perpendicular planes. In this case, 2-8 cm is the norm, 1-2 cm is the borderline state; <1 cm - lack of water :> 8 cm - polyhydramnios. Ultrasound helps to diagnose porn fetal development, which often occur in this pathology of amniotic fluid.

An additional method of multivariate testing is the triple test (determination of the concentration of α-fetoprotein, chorionic gonadotropin, free estriol in the serum of the pregnant woman in 16-18 weeks), which makes it possible to suspect the developmental defects of the fetus, placental pathology. The content of prolactin in comparison with its norm for a given gestation period.

Given the possibility of an infectious genesis of polyhydramnios, as well as the important role of the isoserological incompatibility of maternal and fetal blood in the development of polyhydramnios, it is recommended to carry out a test for TORCH infection and for antibodies to the Rh factor and hemolysins in the case of ABO or Rh contralateral conflict.

[18], [19], [20], [21], [22]

Treatment of polyhydramnios

Pregnant women diagnosed with polyhydramnios should be hospitalized and carefully examined to determine the cause of its occurrence (presence of chronic infection, malformations of the fetus, diabetes mellitus, Rhesus isensensibilization, etc.). Treatment of polyhydramnios depends on the nature of the revealed pathology. In the presence of malformations of the fetus, incompatible with life, pregnancy is interrupted.

In parallel with the pathogenetically substantiated therapy in acute polyhydramnios, antibiotic treatment (rovamycin, etc.) is performed, and amniocentesis is sometimes performed with the removal of a part of the amniotic fluid (the effectiveness of such intervention is rather low and the probability of complications is high). It should be remembered that amniocentesis is not a medical procedure. After its carrying out the volume of amniotic fluid is quickly restored. There are data on the treatment of polyhydramnios indomethacin (25 mg every 6 hours), although there is a potential risk of premature closure of the arterial duct in the fetus.

The course and management of labor during polyhydramnios

Possible complications of labor in polyhydramnios:

• malposition;
• premature discharge of amniotic fluid;
• prolapse of umbilical cord loops and small parts of the fetus during the outflow of amniotic fluid;
• weakness of labor (due to overstretch of the uterus, reduction of contractile activity);
• premature detachment of the placenta (due to rapid discharge of amniotic fluid);
• bleeding in the consecutive and early postpartum periods (hypotension of the uterus due to overstretch).

Thus, during labor, it is necessary to prevent the above-described complications.

Particular attention should be paid to the condition of the fetus, given the fact that the level of perinatal losses in polyhydramnios is 2 times higher. Newborns also require special attention, given the possibility of intrauterine infection, congenital malformations, hemolytic disease.