The Risks Of Having Low Amniotic Fluid
A baby in its mother’s womb is enclosed in a bag called as amniotic sac. In this sac, the baby lives in amniotic fluid and this fluid is formed by the mother initially, but as soon as the baby develops kidneys, a majority of the fluid is contributed by the baby’s urine. The continuous cycle of swallowing and urinating, keeps the fluid circulating and this has many functions in the baby’s development.
Functions Of Amniotic Fluid
- Provides a cushion effect for the baby from outside injuries, if any
- As the baby keeps moving in the fluid, it helps in bone development
- It also helps in lung development
- This fluid maintains optimum temperature for the baby and keeps it warm and healthy
- As a foetus swallows amniotic fluid, it helps in developing its digestive system
The maximum amount of amniotic fluid is at 34 weeks of gestation when it is around 800ml and at term, it reduces to approximately 600ml. There are problems if the amniotic fluid is too low or too high. And these conditions are called oligohydramnios, and polyhydramnios respectively.
Oligohydramnios
This is a condition in which, the amount of fluid in the baby bag is less as compared to the normal requirement for that gestation. It usually happens in late pregnancies, but in some cases, an early onset of oligohydramnios is also seen, mostly associated with genetic disorders.
Measurement Of Amniotic Fluid
Amniotic fluid can be measured during an ultrasound. It is measured either as the deepest pocket of amniotic fluid (it should be free from umbilical cord) or measuring amniotic fluid index called as AFI (this is a sum of deepest pockets of all four quadrants). In a normal situation, the deepest pocket should be more than two centimetres or AFI should be between eight centimetres to twenty-five centimetres.
Causes of Low Amniotic Fluid
Maternal Causes
- Maternal hypertension
- PIH
- Diabetes
- Chronic diseases
- Use of certain medications such as ACE inhibitors (contraindicated in pregnancy)
- Dehydration (rarely)
- Post-date pregnancy
Foetal Causes
- Birth defects such as developmental detect with the kidneys leading to low urine production
- PROM – prelabour rupture of membrane, where the baby bag ruptures and fluid starts leaking
- Placental causes where inadequate blood, nutrition and mineral supply may lead to stoppage of recycling enough fluid
- Certain genetic disorders
Risks Of Having Low Amniotic Fluid
Amniotic fluid is essential for the development of the foetus, as it helps in movement and the development of bones, respiratory and digestive system. The effects of less amniotic fluid depends on during which gestation of pregnancy it happens, if it occurs early in the pregnancy, the results can be lethal, but if it happens in the late trimester, it can be managed and the baby can be salvaged as well.
Effects of Low Amniotic Fluid (1st Half Of Pregnancy)
- Compression of foetal organs, resulting in birth detects
- Compression of the umbilical cord, resulting in intra-uterine death of the foetus
- Increased chance of miscarriage
Effects Of Low Amniotic Fluid (2nd Half Of Pregnancy)
- As the baby does not get enough space to grow, it leads to Intra-uterine Growth Restriction (IUGR)
- Cord compression
- Increased foetal distress and passage of meconium during labour
- Premature delivery
- More chances of caesarean delivery
Treating Low Amniotic Fluid Levels
Treatment depends on when it is diagnosed, either in the first half of the pregnancy or second half of the pregnancy. If diagnosed in the first half of the pregnancy and the baby has severe detects, then usually a termination is done, with emphasis on knowing the cause of oligohydramnios by genetic and other required testing. If it happens in the second half of the pregnancy, then regular monitoring is advised by the doctor like Daily Fetal Movement Count (DFMC), Doppler, NST and AFI. Depending on clinical and investigation reports, doctor may decide for an early delivery, as the baby may do better outside the womb.
Other Treatments
- Some adjuvant treatments can be of help during the management of low amniotic fluid, such as amnioinfusion during labour, using a catheter to help relieve compression on the umbilical cord during labour.
- Increasing maternal fluid intake by IV fluid and oral intake.
- Supplements like protein and arginine.