Oligohydramnios is an abnormally small amount of amniotic fluid during pregnancy. In normal pregnancy, amniotic fluid measures about 800 ml at term.
What is oligohydramnios?
Oligohydramnios is an abnormal condition where the amniotic fluid is less than expected for gestational age. It may be 300 to 500 ml at term and it can be even less.
Amniotic fluid is a water-like fluid that is present around the foetus during pregnancy. It protects the foetus from external injuries and infections. It also allows for growth and free movement of the fetus and prevents adhesions between the fetal parts and the amniotic sac. It reaches its peak of 1 litre at 38 weeks thereafter the amount diminishes till at term. Too little amniotic fluid during pregnancy causes health problems in the foetus and affects its growth and development and can lead to complications during delivery.
What causes oligohydramnios?
The exact cause is not known. But some of the associated factors include
- Presence of fetal chromosomal anomalies
- Intrauterine infections
- Drugs (PG inhibitors and ACE inhibitors) may cause a reduction in amniotic fluid
- It is found to be associated with renal agenesis(absence of kidneys) or obstruction of the urinary tract of the foetus in the first half of the pregnancy which prevents urination leads to oligohydramnios
- Intrauterine growth restriction associated with placental insufficiency
- Failure of the cells of the amnion covering the placenta to secret amniotic fluid
- Pre eclampsia
- Reduction of amniotic fluid also occurs in postmaturity or post-term pregnancy due to the development of placental insufficiency. Perfusion of the fetal organs reduces due to poor placental function. As urine is the major component of amniotic fluid, the decrease in the foetal urine formation leads to oligohydramnios
- Having a previous history of oligohydramnios.
What are the signs and symptoms of oligohydramnios?
- Uterus size is small
- Less weight gain
- Fetal movements are less
- Malpresentation like breech is common
- Leaking of amniotic fluid
- Premature rupture of the membranes
- Fetal parts can be felt easily because of scanty fluid
- Abdominal discomfort
- Ultrasound may show less amniotic fluid.
How is oligohydramnios diagnosed?
Oligohydramnios is usually diagnosed during pregnancy by ultrasonography, findings such as amniotic fluid index(AFI) is less than 5 cm and reduced amniotic fluid volume suggestive of oligohydramnios.
Amniotic fluid can be measured during pregnancy in two ways such as amniotic fluid index (AFI) or maximum vertical pocket (MVP).
What are the complications of oligohydramnios?
- Fetal deformity can occur due to compression caused by less amniotic fluid
- Umbilical cord compression
- Preterm birth or stillbirth
- Prolonged labour
- Increased risk of cesarean section
- Respiratory problems in the baby due to underdeveloped lungs
- Intrauterine growth retardation
- Increased risk of infection of the birth canal due to early water break.
What is the treatment of oligohydramnios?
The woman with severe oligohydramnios may be admitted to the hospital. To prevent compression deformity and prolong the pregnancy, prophylactic amnioinfusion with normal saline, ringer’s lactate or 5% glucose may be performed. Increased water intake will help you to expand the amniotic fluid, so drink plenty of water.
If you are close to term, that is 37 weeks of pregnancy then the safest option is to induce labour because of the possibility of placental insufficiency. Fetal heart rate monitoring is very important during labour because fetal distress occurs frequently. There may be a need for epidural analgesia because uterine contractions are very painful with this condition.
Once the diagnosis is confirmed, the doctor may monitor your condition more closely during antenatal visits to prevent any complications that may arise due to the condition.
How can I prevent the oligohydramnios?
Actually, there is nothing to do to prevent the condition. Have regular antenatal visits and attend all your checkups during pregnancy. If you experience any symptoms or found decreased fetal movements, contact your healthcare provider immediately.
Oligohydramnios is a serious condition but can be treated and you can have a healthy baby.
In the above post, we discussed oligohydramnios (low amniotic fluid), their causes, symptoms, diagnosis, complications and treatment.