Premature outflow of amniotic fluid

Premature rupture of membranes - this spontaneous break before the beginning of labor during pregnancy from 22 to 42 weeks. The frequency of premature discharge of amniotic fluid is from 10 to 15%, depending on the period of pregnancy.

The amniotic fluid is a biologically active environment surrounding the fetus, an intermediate between it and the mother's body, which throughout the entire pregnancy! And in childbirth performs a variety of functions. Normally their amount is about 600 ml; fluctuations depend on the gestational age - from 300 ml (20 weeks) to 1500 ml (40 weeks). At full term, amniotic fluid is a product of secretion of the amniotic epithelium, transudation from the vessels of the decidual membrane and the function of the kidneys of the fetus, are derived by placental and paraplacental pathways. For 1 hour, there is replacement of 200-300 ml of amniotic fluid, and full - for 3-5 hours. In addition, amniotic fluid is an important part of the protective system, preventing mechanical, chemical and infectious effects. In case of physiological pregnancy amniotic fluid retains sterility. The amniotic fluid has antimicrobial activity, due to the production of interferon by fetal membranes, contains lysozyme, antibodies to certain types of bacteria and viruses, immunoglobulins.

[1], [2], [3], [4], [5], [6]

Causes of premature discharge of amniotic fluid

In the etiology of premature discharge of amniotic fluid, there are several reasons:

• infection (amnionitis, ivervicitis, vaginitis of streptococcal or other etiology);
• uterine overgrowth (polyhydramnios and / or crowded pregnancies);
• narrow pelvis;
• extensible insertion of the head;
• pelvic presentation;
• malposition;
• malformations of the fetus;
• structural changes in tissues (due to insufficient intake of ascorbic acid and trace elements, in particular copper);
• injury.

The most frequent factor is infectious. Ascending cervical and vaginal infection leads to contamination with bacteria that release collagenase, which reduces the strength and elasticity of the membranes.

A direct relationship has been established between the intake of vitamin C in the body and the degree of collagen degradation leading to a premature outflow of amniotic fluid. A relationship was found with the level of insulin-like factor in the vaginal secret, with an increase in which the risk of premature rupture of membranes increases dramatically. The outcome of this confirmed the role of ascorbic acid, a-tocopherol, retinol and beta-carotene in the prevention of premature discharge of amniotic fluid. In addition, it is proved that the mechanical strength of the fetal bladder depends on the content of surface-active phospholipid (amniotic surfactant).

With the onset of labor, the bactericidal activity of amniotic fluid decreases, they can delay the development of microorganisms only for 3-12 hours, and later become a breeding ground for their reproduction.

With the rupture of the membranes, the possibility of the penetration of microorganisms into the amniotic fluid significantly increases until the moment of delivery. If the duration of anhydrous period exceeds 6 hours, 50% of children are born infected, more than 18 hours - the seeding of amniotic fluid sharply increases. The development of chorioamnionitis and postpartum infectious complications is observed in 10-15% of cases, despite the ongoing prevention.

The most frequent complication of labor in the premature discharge of amniotic fluid is the weakness of labor. The primary weakness of labor is observed in 5.7 times, and secondary - 4 times more often compared with physiological births. This is due to the lack of increase in the concentration of prostaglandin after premature discharge of amniotic fluid, inhibition of lipid peroxidation, insufficient amounts of oxytocin, low production of prostaglandin chorion cells due to high progesterone production.

[7], [8], [9]

Diagnosis of premature discharge of amniotic fluid

When examining the cervix in the mirrors, the outflow of amniotic fluid from the cervical canal is visually established. In case of difficulty in diagnosing, the amniotic fluid and urine, the increased secretion of amniotic fluid and cervical glands before delivery are differentiated using one or more of the following tests:

• nitrazine. A few drops of fluid taken from the vagina are applied to a strip of nitrazine paper. If there is an amniotic fluid, the paper is painted dark blue;
• Fern test - the phenomenon of the formation of the fern leaf pattern (arborization). A cotton swab is taken from the external cervical canal area of the cervix, a thin layer is applied to a clean slide, after which the drug is air dried for 5-7 minutes. The drug is viewed under a microscope at low magnification. Determination of crystallization in the form of a leaf fern or tree structure is a confirmation of the presence of amniotic fluid. "Fern leaf", which is formed during the arborization of the amniotic fluid, has more branches than in the arborization of cervical mucus. The fern test is considered more accurate than nitrazine;
• cytological. Determining cells of amniotic fluid in a vaginal smear produces less false results than a nitrazine test, and may be the most accurate for confirmation of a diagnosis;
• pH determination using a test strip. The amniotic fluid has an alkaline reaction (pH 7.0-7.5), and the vaginal content is normal - acidic (pH 4.0-4.4). A sterile cotton swab is taken from the portion of the external throat of the cervix of the uterus, applied to the test strip. Staining the strip in blue-green (pH 6.5) or blue (pH 7.0) indicates the presence of amniotic fluid in the test material. False positive results are possible when contaminated with blood, urine or antiseptics;
• research of smears of moisture-sensitive content by the method of LS Zeyvang. On the slide, 1-2 drops of vaginal contents are applied and 1-2 drops of a 1% aqueous solution of eosin are added, followed by viewing in a light-optical microscope at low magnification. In the case of the outflow of amniotic fluid in the test fluid among the bright pink epithelial cells of the contents of the vagina and erythrocytes, accumulations of unstained, non-nucleated cells of the fetal epidermis are determined, which do not perceive the paint due to the coating with original grease;
• ultrasonography. If a sufficient amount of amniotic fluid is determined, the diagnosis of premature rupture of membranes is uncertain. In the case of the definition of malnutrition and if there is at least one positive test for amniotic fluid, a diagnosis of premature discharge of amniotic fluid is established.

Spontaneous labor (without attempts at its induction) with full term pregnancy develops in 70% of pregnant women during the first 24 hours from the moment of detection of rupture of membranes, and in 90% in the first 48 hours. The waiting tactics in these cases in the absence of spinal manifestations of infection and timely antibiotic prophylaxis does not increase the frequency of purulent-inflammatory complications in the parturient and newborn.

[10], [11]

Management of pregnant women with premature release of amniotic fluid

It is necessary to hospitalize in the midwifery hospital III level of medical care from 22 to 34 weeks of pregnancy. Before the transfer of a pregnant woman from midwifery hospitals I-II level to institutions of the third level of medical care, an external obstetrical examination, examination of the cervix in the mirrors and auscultation of the fetal heartbeat are carried out. In case of confirmed premature rupture of amniotic fluid, it is necessary to begin prophylaxis of respiratory distress syndrome: dexamethasone is administered intramuscularly at 6 mg every 12 hours, for a course of 24 mg (A) or betamethasone 12 mg every 24 hours, for a course of 24 mg (A).

From the 35th week of pregnancy, delivery can be performed at level II facilities, if necessary, with a call from a high-level healthcare provider.

The main stages of in-hospital examination during admission:

• the establishment of a gestational age;
• determination of the approximate time of rupture of membranes according to the history;
• diagnosis of the presence of labor by methods of external examination;
• examination of the cervix in the mirrors (vaginal examination in the absence of labor and contraindications to expectant management of pregnancy is not carried out);
• confirmation of diagnosis by laboratory methods in doubtful cases;
• Ultrasound with the definition of amniotic fluid volume;
• bacterioscopic examination of vaginal discharge with Gram staining.

Management of pregnant women with premature rupture of membranes

Depending on the period of pregnancy, concomitant pathology, obstetric situation and obstetric-gynecological history, individual tactics of reference are chosen.

In all cases, the patient and her family should receive detailed information about the condition of the pregnant and fetus, the benefits of the possible danger of some form of further management of pregnancy with the receipt of written consent of the patient.

Expectant tactics (without induction of labor activity) can be chosen:

• in pregnant women with a low degree of predictable perinatal and obstetric risk;
• with a satisfactory condition of the fetus;
• in the absence of clinical and laboratory signs of chorioamnionitis (increase in body temperature above 38 ° C, specific odor of amniotic fluid, palpitation of the fetus more than 170 per 1 minute, the presence of two or more symptoms gives grounds for establishing the diagnosis of chorioamnionitis);
• in the absence of complications after the outflow of amniotic fluid (prolapse of the umbilical cord, placental abruption and the presence of other indications for urgent delivery).

In case of choosing expectant tactics »in obstetric hospital it is necessary to conduct:

• measuring the body temperature of a pregnant woman twice a day;
• determination of the number of leukocytes in the peripheral blood, depending on the clinical course, but not less than once in a day;
• bacterioscopic examination of vaginal discharge once in three days (with counting the number of white blood cells in the smear);
• observation of the fetus by auscultation twice a day and, if necessary, recording CTG at least once a day from the 32nd week of pregnancy;
• warn the pregnant woman about the need for an independent test of fetal movements and contact with the doctor on duty in case of changes in the motor activity of the fetus (too slow or violent);
• preventive administration of semisynthetic penicillins or cephalospores of the 2nd generation in average therapeutic doses from the moment of hospitalization for 5-7 days in the absence of signs of infection in the pregnant woman.

In the period of pregnancy 22-25 weeks:

• monitoring of the state of the pregnant and fetus without an internal obstetric examination is conducted in the midwifery hospital level III level of medical care;
• antibiotic therapy from the moment of admission to an obstetric hospital.

In the period of pregnancy 26-34 weeks:

• monitoring of the state of the pregnant and fetus without an internal obstetric examination is conducted in the midwifery hospital level III level of medical care;
• antibiotic therapy from the moment of admission to the obstetric hospital;
• prevention of respiratory distress syndrome of the fetus by intramuscular injection of dexamethasone 6 mg every 12 hours (per course of 24 mg) or betamethasone 12 mg every 24 hours (per course of 24 mg). Repeated prevention courses are not available.

In the period of pregnancy 35-36 weeks:

• possible expectant or active tactics;
• with a satisfactory condition of the pregnant and fetus and the absence of indications for operative delivery, monitoring is conducted without internal obstetric examination in health facilities of II-III level of medical care;
• antibacterial therapy is started after 18 hours of anhydrous period;
• in the absence of development of spontaneous labor activity, an internal obstetrical examination is performed 24 hours later;
• with the mature cervix of the uterus, the induction of labor begins in the morning (no earlier than 6:00) with oxytocin or irostagl andndines;
• with the immature cervix of the uterus preparing for childbirth by intravaginal injection of prostaglandin E2;
• in the presence of indications, rhinorrhea is performed by cesarean section.

In the period of pregnancy 37-42 weeks:

• in the absence of development of spontaneous labor activity, an internal obstetrical examination is performed 24 hours later;
• with the mature cervix of the uterus, induction of labor in the morning (no earlier than 6:00) oxytopin or prostaglandin E2;
• with the immature cervix of the uterus preparing for childbirth is performed by intravaginal injection of prostaglandin E2;
• in the presence of indications, the delivery is prescribed by cesarean section.

Tactics of management of pregnant women in the presence of infectious complications

In the case of development of chorioamnionitis, abortion is indicated.

In the treatment regimen, cephalosporins II-III generation and metronidazole (or ornidazole) are prescribed 30 minutes prior to the administration of cephalosporins.

The method of delivery is determined by the period of pregnancy, the state of the pregnant and fetus, the obstetric situation.

In the case of operative delivery, intensive antibiotic therapy is performed in the treatment regimen for at least 7 days.

Thus, premature discharge of amniotic fluid is accompanied by a number of serious complications, which requires improving the tactics of giving birth and antenatal protection of the fetus in this pathology, the prevention of purulent inflammatory diseases in the parturient and newborn, and special attention in the management of the early neonatal period.

ICD-10 code

According to the International Classification of Diseases of the 10th revision (ICD-10), the code for premature rupture of membranes is 042:

• 042.0 Premature rupture of membranes within 24 hours before the onset of labor;
• 042 1 Premature rupture of membranes, onset of labor after 24 hours of anhydrous period;
• 042.2 Premature rupture of membranes, delay in labor associated with therapy;
• 042.9 Premature rupture of membranes, not specified.