During pregnancy, your healthcare provider will likely remind you often to drink plenty of water. We’ve all grown up hearing how important hydration is—stay hydrated! But how does this apply when you’re expecting?

Let’s start with a common term you may hear: A.F.I.
AFI stands for Amniotic Fluid Index, which is how ultrasound technicians measure the amount of fluid surrounding your baby. They take measurements from four different vertical sections of your uterus, looking for the deepest pockets of fluid. These measurements are added together to calculate your AFI.

The normal AFI range is above 5 cm and below 25 cm.

• Less than 5 cm is called Oligohydramnios

• More than 25 cm is called Polyhydramnios

So how is amniotic fluid made?

Amniotic fluid begins forming about 12 days after conception, during the first trimester. At this early stage, it’s made up primarily of water.

By the second trimester, your baby starts contributing—amniotic fluid becomes mostly made up of your baby’s urine. Yep, you read that right—your baby is peeing into the fluid!

It might sound a little gross, but it’s actually a really good sign of healthy development. Why?

Because amniotic fluid plays an important role in your baby’s growth. It helps your baby learn to swallow, supports the development of the kidneys and urinary tract, and teaches them how to pee. It’s all part of a beautiful, self-regulating cycle.

Staying well-hydrated during pregnancy is essential—not just for you, but for your baby too. Your AFI (Amniotic Fluid Index) plays a big role in supporting your baby’s development. It provides several important benefits:

• Cushions your baby, protecting them from bumps and pressure

• Supports the development of body parts, like the lungs and digestive system

• Gives your baby room to move around, which helps with muscle development—and let’s be honest, those little kicks and flips are always reassuring!

• Helps prevent infections by creating a barrier from outside germs

There are many reasons why your amniotic fluid levels might increase or decrease—and some of them are completely out of your control.

For example, if you’re in your third trimester, you might notice a natural decline in fluid levels. This is typically normal as you near your due date—your AFI will usually decrease on its own during this time.

The best thing you can do? Stay hydrated! And if you’re unsure how much water you should be drinking, don’t hesitate to ask your healthcare provider.