Definition
Oligohydramnios is a condition that can occur during pregnancy, characterized by a quantitative reduction of the amniotic fluid.
In most cases, this phenomenon does not compromise the outcome of gestation, which proceeds normally. In late pregnancy, moreover, a slight reduction in the volume of liquid within the amniotic sac can be considered a "paraphysiological" condition (ie almost normal in some respects).
However, when the oligohydramnios develops in the first and second trimester, it can predispose to the onset of complications, such as atelectasis, insufficient development of the fetus in the lung and perinatal respiratory disorders (respiratory distress syndrome). In fact, the child is compressed against the walls of the maternal uterus and there may not be enough space for its growth; this state of suffering can result in malformative diseases (such as clubfoot and hip dysplasia). The mother can also experience fetal movements with particular intensity, as well as the baby's heartbeat. During labor, lacking the protective action of the amniotic fluid, the fetus can go more easily to suffering.
The oligohydramnios is frequently found in pregnancies beyond the term. The amniotic fluid may decrease due to the altered permeability of the membranes or the premature rupture of the same, such as during cytomegalovirus or toxoplasmosis infections. In some cases, the oligohydramnios is also caused by the mother's poor fluid intake or a strong state of stress.
Rarely, oligohydramnios may indicate a fetal malformation related to the digestive or urinary tract, as urine is one of the main constituents of amniotic fluid. Fluid deficiency may also reflect poor placental blood flow and, therefore, may be associated with fetal growth retardation.
The total absence of liquid is called anhydramnios.
Possible Causes * of Oligohydramnios
- Gestational diabetes
- Cytomegalovirus infection (CMV)
- Hypertension
- Pre-eclampsia
- Down syndrome
- Toxoplasmosis
- Trisomy 18
