Amniotic fluid: What you need to know

Here are some important questions to ask about amniotic fluid.

What is amniotic fluid and why do we have it?

Before 20 weeks, amniotic fluid is similar to blood plasma. After 20 weeks, it is mainly made of your baby’s urine, mixed with vernix and sloughed off skin cells. The baby keeps the fluid at a constant level by swallowing it. It cushions the baby, maintains temperature and gives space for your baby’s lungs and limbs to develop properly. 

How is amniotic fluid measured? 

Amniotic fluid is measured by ultrasound, either by measuring the largest vertical fluid pocket, or by measuring the largest pocket in each of the four quadrants of the uterus and adding them together. This is called the Amniotic Fluid Index (AFI). A normal AFI ranges from five to 25. 

Can I have too much amniotic fluid? 

Yes, this is called polyhydramnios. The most common cause is diabetes, but it can also happen if the baby has a neurological disorder or a malformation of the heart or stomach. Anything that interferes with baby’s swallowing can lead to a buildup of fluid. This can be uncomfortable. Because of the pressure caused by the extra fluid, your risk of going into early labour can increase. Fluid can be drained off by doing an amniocentesis, which treats the symptoms but not the reason for the excess fluid.

What does it mean if my fluid level is low?

This is called oligohydramnios. It happens after you break your water, but if that is not the case, it can be a sign that the placenta isn’t working properly. Fluid is your baby’s urine, so if it is not getting enough nutrients from the placenta, it will make less, just like we do when we get dehydrated. In that case, your doctor will likely monitor you more closely with ultrasounds and non-stress tests.

How do I know if I broke my water? 

You may feel a big gush of fluid or a slow, steady leak. The fluid is usually clear, but it can sometimes be blood-tinged or brown. You may have contractions, but you might not. It can happen at any time during your pregnancy, so you should call your doctor or hospital right away if you think you are leaking.

How do they check if I broke my water?

It’s important to make sure that the fluid is coming from the uterus. Other things like urine and discharge can feel like leaking. Your doctor will likely look inside the vagina with a speculum (like during your pap smear) to see if there is fluid leaking from the cervix. Sometimes it’s obvious, but if not, the doctor will sample any fluid with a pH swab and look at it under a microscope. If the swab turns blue and there is a specific pattern on slide, then you’ve broken your water! There are some new lab tests that check for amniotic fluid, but not all hospitals have them.

What do I do if I break my water at the grocery store? 

Drop a jar of pickles on the ground to camouflage the puddle and get to the hospital!