The fundal height is yet another puzzling medical term in a long list of pregnancy-related jargon. And it’s one you’ll hear a lot of as the weeks go by. If you’re not quite sure what it actually means, don’t worry. We’ve got you.
Your doctor or midwife will start measuring the fundal height at your antenatal appointments from about 20 weeks onwards. Its purpose is to keep track of your baby’s growth, providing you with a lovely little snapshot of how your baby is developing throughout your pregnancy.
What is fundal height?
Your fundal height is the vertical measurement in centimeters, from your pubic bone up to the top of your uterus, which is called the fundus. Simple really!
From about 24 weeks gestation, the average fundal height matches the week of pregnancy. Your doctor will be able to feel the top of your uterus by pressing around the top of your baby bump, but this measurement is not always super accurate.
It can be more difficult to measure an accurate fundal height if you have a high BMI or if you have a history of uterine fibroids. But it’s normal for everyone’s fundal height to sit somewhere +/- 2cm from your gestational week.
In other words, if you’re 25 weeks pregnant, a normal fundal height would sit somewhere between 23cm-27cm.
What does fundal height tell you?
Taking your fundal height measurement is an easy way for your healthcare provider to keep track of your baby’s growth, without the need for additional ultrasounds. But does fundal height indicate baby size only? Nope! The fundal height measurement also provides your doctor with a way to track your baby’s position, and the amount of amniotic fluid there is in your uterus.
Fundal height measurements are also often the first indication that something may be developing differently for your baby. Don’t panic, a lot of the time a fundal height outside of the average range will mean something like a slightly inaccurate conception date or due date, meaning you’re not as far (or perhaps even further along) than you thought you were.
But if your fundal height measurement is +/-3cm from your gestational age, your doctor may suggest an ultrasound or further investigation in order to make sure everything is A-OK.
An unusual fundal height may indicate:
- A small baby — possibly the presence of intrauterine growth restriction
- A large baby — macrosomia, which can be an indicator for gestational diabetes
- A multiple pregnancy — surprise, it’s twins!
- Too much amniotic fluid — called polyhydramnios
- Not enough amniotic fluid — called oligohydramnios.
Or it could just mean that you’re carrying a perfectly healthy baby, who is going to be slightly smaller, or bigger, than average. If you or your partner are on the small (or tall!) side, this may not come as much of a surprise.
Should your fundal height keep increasing?
Up until around week 36, you will expect an increase of your fundal height by week, as you progress through pregnancy. As you near your due date, though, you may well see your fundal height drop. This isn’t anything to worry about. In fact, it’s a positive sign!
Generally speaking, at this point in pregnancy, a decreasing fundal height indicates that your baby’s position has dropped. Your baby dropping, and engaging their head down into your pelvis, means they’re getting ready for their big entrance into the world.
On the other hand, if your fundal height doesn’t start decreasing, it may indicate that your baby is in a breech position. Your doctor will be able to feel this too, by touching your baby bump to check exactly where the baby is resting.
How do you measure fundal height?
To measure your fundal height, your healthcare provider will first ask you to lay down on your back. You will need to loosen your pants so they can get right down to your pubic bone, and lift your top so they can find the top of your uterus. They’ll then use a tape measure and place it tight to your skin, measuring vertically up the front of your baby bump.
It’s quite hard to feel for your own fundus, but generally, it will feel quite firm, whereas the abdomen above will be softer. If you’re wondering how to measure the fundal height at home… well, it’s probably not that easy!
As it’s not the most accurate measurement to take yourself, it’s probably best to leave this one to the professionals to save yourself any worry over an inaccurate DIY measurement.
What is more accurate, fundal height or ultrasound?
An ultrasound is a more accurate pregnancy measurement to track your baby’s growth when compared to the fundal height measurement. Having said that, even ultrasounds aren’t completely accurate and can show variations of 10-20% when measuring your baby — and up to a 500g difference when predicting their weight.
However, ultrasounds do provide a much more detailed look at your baby’s body parts, their position, and the amniotic fluid surrounding them. Sonographers log their measurements of your baby into a computerized algorithm that compares them with average measurements for their gestational age. If your fundal height measurement is flagged as unusual, you will often be referred for an ultrasound scan for a more in-depth analysis of your baby’s growth.
As always, mama, you know your body — and your baby — best of all. If you have any concerns, make sure to speak to your doctor or midwife.