What Your Fundal Height Measurement Means

One of these measurements is known as fundal height. Here’s what you should know about fundal height, and what it means for your developing baby.

What Is Fundal Height?

Fundal height is the measurement from your pubic bone to the top of the uterus, or the fundus, in pregnancy.

Fundal height measurements help your doctor understand things like your baby’s size, growth rate, and position in your uterus, as well as how much amniotic fluid there is around the baby. In other words, “It’s a rough estimate for fetal growth,” says Jennifer Hong, M.D., a board-certified ob-gyn at Atrium Health in Fort Mill, South Carolina.

When Do Fundal Height Measurements Begin?

Your doctor will start taking fundal height measurements between 20 weeks and 24 weeks of pregnancy. There’s no need to measure any earlier than that.

“Up until about 12 weeks of pregnancy, the entire uterus is way down low in the pelvis. We can’t even feel it,” explains Clayton Alfonso, M.D., a board-certified ob-gyn at Duke Health in Durham, North Carolina. “Between 12 and 20 weeks, as the developing fetus is growing bigger, the uterus starts to come out of the pelvis, into the abdominal cavity. And around 20 weeks of pregnancy, we should be able to feel the top of the uterus right around the belly button.”

What Should Each Fundal Height Measurement Be?

Fundal height can be somewhat predictable. “Typically, pregnant women will measure about 1 centimeter per week of gestation,” Hong says. It’s common for these weekly measurements to fall within a range of plus or minus 2 centimeters (cm).

A measurement outside that range is usually worth checking out.

Fundal Height by Week

The following fundal height chart can help you reference typical measurements from week to week.

After week 36 of pregnancy, fundal height becomes less predictable. This is when the baby may start to drop down in the pelvis in preparation for labor and delivery. As a result, fundal height measurements may start to go down, and they may not need to be monitored as closely.

If fundal height measurements don’t go down after week 36, it may be a sign that your baby is breech. If needed, your doctor may order additional tests or an ultrasound to monitor your baby as your due date nears.

Why Is Measuring Fundal Height Important?

Measuring and tracking fundal height at each prenatal appointment “gives us multiple data points throughout the pregnancy to ensure that the baby is growing appropriately and that the fluid levels are normal,” Hong says.

Many pregnancies only get one or two ultrasounds: one in early pregnancy to establish viability and due date, and one between 18 and 22 weeks for a detailed view of fetal anatomy from head to toe.

“The vast majority of low-risk individuals don’t get another ultrasound,” Alfonso says. “So, fundal height is our way of checking to make sure the baby is growing appropriately.” If there’s a concern, your doctor may order a follow-up ultrasound to check your baby’s growth.

What Does It Mean If Fundal Height Measurements Are Different?

If fundal height is measuring larger than expected, it could be a sign that:

• Your baby is larger than expected.
• You’re pregnant with twins or other multiples.
• There’s too much amniotic fluid around the baby.
• Your original due date is wrong.
• Your body mass index (BMI) is 25 or higher.
• The baby is in a breech position.
• Your bladder is full.
• Your abdomen is stretched from previous pregnancies.

If fundal height is measuring smaller than expected, it could be because:

• Your baby is smaller than expected.
• You’re of smaller stature.
• You have strong abdominal muscles.
• There’s not enough amniotic fluid around the baby.
• The baby has already dropped into the pelvis in preparation for labor and delivery.

If your doctor notices any discrepancies between your fundal height measurements, they’ll likely order an ultrasound to take a closer look. This imaging test allows them to address or rule out any potential abnormalities.

In most cases, though, the baby is likely developing normally. “Sometimes, we’ll find that somebody doesn’t measure on target, but then an ultrasound confirms that everything is okay,” Hong says.

Fundal Height Measurements Are Individualized

When measuring fundal height, your doctor considers more than just the number. “We look at the trend of what your growth has been,” Alfonso says. Meaning, if you always measure 1 centimeter lower or higher than expected, “that tells us you’re consistent with how growth is going,” he explains, adding the caveat, “If you didn’t follow your own growth curve, we might be worried that the baby’s not growing appropriately—even if you’re within that 2-centimeter range.”

And if you have a high-risk pregnancy or a chronic health condition, fundal height measurements may be less important. “In those pregnancies, you have a higher risk of the baby being either too big or too small,” Alfonso says. “So, most of those individuals get third-trimester ultrasounds to evaluate fetal growth.”

Can You Measure Fundal Height Yourself?

It’s important to leave these measurements to your healthcare team rather than trying to measure yourself. “It’s very hard to feel where the fundus ends on your own body, and trying to do it yourself can just lead to a lot of unnecessary worry and anxiety,” Hong explains.

What Happens to Fundal Height Postpartum?

Shortly after the baby and placenta are delivered, the uterus continues to contract, and the fundus should shrink down to your belly button, or where it was around 20 weeks of pregnancy.

By one week postpartum, the fundus should shrink down to your pubic bone, or where it was around 12 weeks of pregnancy.

“By the time you come back to your postpartum visit, the uterus is nearly back to normal size, all the way down in the pelvis,” Alfonso says.

Then, notes Hong, it may take up to several months for it to get all the way back to its pre-pregnancy size.

You May Also Like:

• A Guide to Your Pregnancy, Week by Week
• The Schedule of Doctor Visits During Pregnancy
• Linea Nigra: The Dark Line on Your Belly, Explained