Amniotic fluid is an important part of what keeps your baby protected in the womb. The amniotic fluid is created as soon as 12 days after the baby is conceived. In the beginning the amniotic fluid consists of water from the mother, but from around 20 weeks it is primarily composed of fetal urine. As the baby grows it will begin to move around in the amniotic fluid, and during the second trimester it will also begin to breathe and swallow the amniotic fluid.
There are cases where there can be too much or too little amniotic fluid, putting the baby in danger. Not enough amniotic fluid is referred to as oligohydramnios, too much fluid is called polyhydramnios.
What Exactly Is Oligohydramnios?
This is the condition where there is too little amniotic fluid in the womb. The amount of fluid in the womb can be measured a few different ways, usually using the amniotic fluid index which uses deep pocket measurements to find out approximately how much amniotic fluid is in the womb. The following can indicate low levels of amniotic fluid:
- Fluid level less than 5cm
- Lack of fluid pocket 2-3cm in diameter
- Volume of under 500mL at 32-36 weeks
Generally speaking, about 8% of women are diagnosed with levels of amniotic fluid, and 4% have low enough levels to be diagnosed with oligohydramnios. While oligohydramnios can be diagnosed at any time during the pregnancy it is most commonly diagnosed in the third trimester. Women are often at risk of low amniotic fluid levels when they go past their due date by two weeks or beyond, and can be responsible for 12% of complications in pregnancies that go more than one week past due.
Causes Of Oligohydramnios
Various conditions can cause low amniotic fluid levels, such as the following:
Birth Defects: Some birth defects that affect the kidneys or urinary tract can also affect urinary production which will result in low amniotic fluid levels in the uterus.
Placental Problems: On occasion the placenta does not provide the baby with enough nutrients and fluid.
Leaking of Membranes: If there is a tearing in the membrane then the fluid may slowly leak out or you may experience a gush of fluid.
Past Due Pregnancy: The longer past due your pregnancy continues, the less amniotic fluid there will be in the uterus.
Maternal Problems: Problems such as dehydration, high blood pressure or diabetes can affect fluid levels.
Risks Of Oligohydramnios
The risks of low levels of amniotic fluid in the womb depend on how far along the pregnancy is. Amniotic fluid is needed to help with development of the baby’s muscles, limbs and digestive system. As the baby develops the process of swallowing the amniotic fluid helps to develop the lungs, and the amniotic fluid gives room for the baby to move around. The complications that can arise due to oligohydramnios can be more severe if in the beginning of the pregnancy such as:
- Excessive pressure on the baby’s organs leading to birth defects
- Higher chance of miscarriage or stillborn birth
If low amniotic levels are detected in the later stages of pregnancy then other complications can include:
- IUGR: Intrauterine Growth Restriction
- Preterm birth
- Other labor complications like cord compression, meconium in the fluid or a caesarean delivery
Treatments For Oligohydramnios
What treatments are recommended for oligohydramnios depends on the gestational age of the baby. Certain tests will be conducted in order to determine the fluid levels and whether the baby can handle the stress of labor. Generally if you are close to full term the best way to resolve the problem is to deliver the baby, but earlier in the pregnancy the following treatments may help:
- Infusion of fluid during labor via a catheter, which helps to pad the area around the umbilical cord and reduce the chances that a casarean will be required to deliver the baby.
- Prior to labor, fluid can be injected using amniocentesis. However, in most cases the low fluid levels will return within seven days.
- In many cases by hydrating the mother with fluid by mouth or IV can help to re-establish the appropriate fluid levels in the womb.