Malopecia: causes, symptoms, diagnosis, treatment

Oligohydramnion - a decrease in the amount of amniotic fluid to 500 ml or less. According to various authors, oligohydramnion occurs in approximately 5.5% of pregnant women.

The complete absence of amniotic fluid is called ahydroamnion. This pathology is extremely rare.

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Causes of oligohydramnios

Pathological conditions in which oligohydramnios may occur:

• associated with maternal illnesses:
  • gestosis;
  • chronic cardiovascular diseases (arterial hypertension);
  • chronic diseases of the urinary and reproductive systems;
  • infectious and inflammatory diseases in the mother, including inflammatory diseases of the female genital organs;
• associated with fetal pathology:
  • pathology of the urinary and reproductive systems;
  • fetal growth retardation syndrome;
  • chromosomal pathology;
  • intrauterine infection;
• associated with placental pathology:
  • placental developmental abnormalities;
  • fetoplacental insufficiency.

Oligohydramnios also occurs in cases of post-term pregnancy, intrauterine fetal death, and premature rupture of the membranes. Idiopathic hydramnios is also distinguished.

The pathogenesis of oligohydramnios has not been sufficiently studied. There are two forms of oligohydramnios:

• early form - diagnosed in the 16th-20th week of pregnancy using ultrasound. Often combined with congenital malformations of the fetus (hypoplasia of the lungs, agenesis or polycystic kidney disease, Ponter syndrome);
• late form - diagnosed after the 26th week of pregnancy, occurs due to insufficient functional activity of the fetal membranes or disturbances in the condition of the fetus.

In case of oligohydramnios, extensive necrosis of the amnion epithelium and blocking of the mechanism of water and urea transport (in case of inflammatory genesis of oligohydramnios), atrophy and sclerosis of the decidual membrane, and pathological development of the chorionic villi (in case of developmental defects) are revealed in the fetal membranes.

In amniotic fluid with oligohydramnios, changes in the levels of human chorionic gonadotropin, placental lactogen, prolactin, and estradiol are determined.

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Diagnosis of oligohydramnios

• lag in the height of the fundus of the uterus and abdominal circumference from the standard values for the expected gestational age;
• decreased fetal motor activity;
• the uterus is dense upon palpation, the parts of the fetus are clearly defined and its heartbeat can be heard;
• during a vaginal examination, a flat fetal bladder is determined, the anterior waters are practically absent, and the fetal membranes are “stretched” on the head of the fetus;

Ultrasound allows for a more accurate determination of the severity of oligohydramnios. The diagnosis of oligohydramnios is established in cases where the AFI index is below 5%.

Treatment of oligohydramnios

To date, effective methods of pathogenetic correction of oligohydramnios have not been developed. When diagnosing oligohydramnios, the following measures should be taken:

• elimination of the cause of oligohydramnios, if it is established (for example, antibacterial therapy for intrauterine infection of the fetus);
• correction of uteroplacental circulation.

In addition, it should be taken into account that if oligohydramnios occurs before the 22nd week of pregnancy, a comprehensive examination must be carried out to exclude fetal malformations.

In turn, oligohydramnios in the third trimester of pregnancy is often combined with intrauterine growth retardation. Given the ineffectiveness of drug treatment for intrauterine growth retardation, the key point in the management of such pregnant women is a clear assessment of the fetus's condition and timely delivery.

If oligohydramnios is detected during labor (flat amniotic sac), amniotomy must be performed.