What Do I Need To Know About Amniotic Fluid?


Amniotic fluid, a humble liquid that protects and nourishes your baby. It also helps maintain a constant temperature; it promotes growth and the development of your baby’s lungs, gastrointestinal system, muscles and bones and it also prevents compression of the umbilical cord.

After 16 weeks, when your baby begins swallowing the fluid, it consists partly of recycled urine. The volume increases from about a cup in the first trimester to four cups by the third trimester, then decreases to about three cups at term. How amazing is that?

With amniotic fluid there are certain pregnancy conditions that relate to the levels of the amniotic fluid that can be a reflection of the health of your pregnancy and baby.

In your antenatal check-ups clues that there is either too much or too little amniotic fluid include a decrease in your baby’s movements plus a too-large or too-small belly when you are measured by the Midwife or Doctor. If the Midwife or Doctor are concerned at all they would order an ultrasound to confirm the exact amount of amniotic fluid that is around your baby.

Let’s discuss the two options and what it could mean.


Too little fluid also known as “Oligohydramnios”.


This occurs in about 4 percent of pregnancies and it can be a signal of birth defects, especially those involving the baby’s kidney or urinary tract. It could also mean that you may have had a premature rupture of your membranes (leaking fluid should be reported to your midwife or doctor immediately); or it could also be caused by maternal health conditions such as diabetes and high blood pressure.

Oligohydramnios can also be caused by placental problems. If the placenta is not providing enough blood and nutrients to the baby, then the baby may stop recycling fluid therefore causing a decrease in your amniotic fluid.


What are the risks of having low amniotic fluid?


The risks associated with oligohydramnios often depend on the gestation of the pregnancy. The amniotic fluid is essential for the development of muscles, limbs, lungs, and the digestive system. In the second trimester, the baby begins to breathe and swallow the fluid to help their lungs grow and mature. The amniotic fluid also helps the baby develop muscles and limbs by providing plenty of room for the baby to move around.

If oligohydramnios is detected in the first half of pregnancy, the complications can be more serious and include:

  • Compression of fetal organs resulting in birth defects
  • Increased chance of miscarriage or stillbirth

If oligohydramnios is detected in the second half of pregnancy, complications can include:

  • Intrauterine Growth Restriction (IUGR)
  • Preterm birth
  • Labor complications such as cord compression, meconium stained fluid and an increased risk of a caesarean section.

What treatments are available if I am experiencing low amniotic fluid?


The treatment for low levels of amniotic fluid is based on gestational age. If you are not full term yet, your doctor will monitor you and your amniotic fluid levels very closely. If you are close to full term, then your baby is usually better off on the outside then on the inside and usually what most doctors recommend in situations of low amniotic fluid levels is to induce your labour and have your beautiful baby in your arms.


Too much fluid also known as “Polyhydramnios”.


This occurs in about 1 percent of pregnancies and it can suggest birth defects, most commonly those of the gastrointestinal and nervous systems that affect swallowing. Some other causes of polyhydramnios include:

  • Fetal abnormalities
  • Maternal diabetes
  • Placental abnormalities

However for many women the cause of the polyhydramnios is often unknown.

Complications of Polyhydramnios.

Depending on the severity, polyhydramnios can increase the risk of some pregnancy complications including:

  • Preterm birth
  • Ruptured membranes
  • Cord prolapse
  • Placental abruption (when the placenta separates from the uterine wall)
  • Postpartum haemorrhage (severe bleeding after the birth of the baby)
  • Malposition of the baby (not coming head first)
  • And in severe cases – stillbirth

Women with polyhydramnios may have abdominal discomfort and breathing difficulties as a result of their increased abdominal size. If you feel like this make sure you discuss your concerns with your doctor.

Treatment of Polyhydramnios.

Some cases of polyhydramnios may require removal of the excess amniotic fluid via a needle (amniodrainage) to reduce the risk of ruptured membranes and preterm birth. The procedure is performed under ultrasound guidance and may need to be repeated multiple times during your pregnancy. Follow the lead of your health care providers to know whether this may be an option or you.

If you have any of these pregnancy conditions your pregnancy will be considered high risk and you will be closely monitored throughout the rest of your pregnancy and birth to ensure that you and the baby are safe.

If the reason for either of these conditions is due to a birth defect, a paediatrician will closely monitor your baby after the birth and any necessary tests will be done as per the paediatrician’s orders.


Midwife Zoe

(This article contains general information only and is not intended to replace advice from a qualified health professional. All information is written from the experience and knowledge of the person writing the post).

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