What to know about fundal height
What to Know About Measuring Fundal Height
Choosing to have a baby can be a magical experience. But there are also many unknowns that come with pregnancy. You’re doing everything you can to care for your body and your unborn child, but you may wonder how to know if your baby is growing well in your uterus (womb).
Measuring fundal height is one way to keep track of your baby’s development while you’re pregnant.
What Is Fundal Height?
It’s the distance from your pubic bone to the top of your uterus.
Measuring your fundal height is one test your doctor may do at your pregnancy check-ups. Other ways they may check on your baby’s health include checking your physical health, running labs on your body, listening to your baby’s heartbeat, checking how often your baby moves, and looking at your baby with an ultrasound.
Doctors combine all of these factors to give you the most accurate understanding of how well your baby is developing.
What Does Fundal Height Tell You About Your Baby?
Doctors use your fundal height measurement to test how well your baby is growing.
It’s one of many tests doctors use to measure your baby’s growth. Your fundal height is compared to your estimated pregnancy date to suggest whether your baby is growing on track.
If your fundal height isn’t what you expect it to be, it doesn’t automatically mean that there’s something wrong with your baby. But if your fundal height is on track, you may be able to rest a little easier knowing your baby is growing the way your doctors are expecting it to.
How Do You Measure Fundal Height?
Understand that even trained doctors can have a hard time measuring it accurately. So, before you try measuring fundal height at home, have your doctor show you where your pubic bone is and how to locate the top of your uterus.
Once you know, here are the basic steps to follow.
- Empty your bladder first. Studies show that a full bladder can change fundal height measurements by several centimeters.
- Next, lay down on your back with your legs out in front of you. Using a tape measure that measures centimeters, place the zero marker at the top of the uterus.
- Move the tape measure vertically down your stomach and place the other end at the top of your pubic bone. This is your fundal height measurement.
What Should Your Fundal Height Be?
Starting at 24 weeks, your fundal height should be about the same number of centimeters as the number of weeks you’ve been pregnant.
Your fundal height may be off by up to 2 centimeters in either direction and still be considered normal.
So, for example, if you’re 30 weeks pregnant, a fundal height of 28 to 32 centimeters is considered to be a normal range.
What Can Impact Fundal Height?
There are a number of things that can affect it. Not all of these factors have to do with your baby. For example, your fundal height measurement may not be accurate if:
- You have a BMI of 30 or more.
- You have a history of uterine fibroids.
- Your bladder is full.
- You’re not lying on your back when you take the measurement.
There are other reasons your fundal height may be bigger or smaller than expected. If your fundal height is larger than expected, it may be because:
- You have too much amniotic fluid.
- You’re having more than one baby.
- Your baby is larger than expected.
If your fundal height is smaller than expected, it may be because:
- Your baby is smaller than expected.
- You don’t have enough amniotic fluid.
- Your baby’s growth is being restricted.
Your fundal height measurement may also be off if your pregnancy is further along, or less far along, than you thought. Your due date is an estimate based on the last day of your last period, so it can sometimes be inaccurate.
Doctors usually use the assumption that you have a standard 28-day period when making their due date predictions. Since periods and ovulation windows can vary, your doctor may have been off by a couple of weeks when first predicting your due date.
What Should You Do if You’re Concerned About Your Fundal Height?
If your fundal height isn’t measuring as expected, your doctor will need to do some follow-up tests to determine the root cause. These tests could include an ultrasound to get a better look at your baby or labs to test the health of your body.
An unusual fundal height measurement on its own is an indication that there’s something happening with your baby.
Once your doctor has figured out why your fundal height measurement is off, they can help you figure out what steps need to be taken next, if any, to help your baby grow at a healthy rate.
Show Sources
King Edward Memorial Hospital Obstetrics and Gynaecology: “Fundal height: Measuring with a tape measure.”
Mayo Clinic: “What’s the significance of a fundal height measurement?”, “Prenatal care: 2nd trimester visits.”
Ohio State University Wexner Medical Center: “What can cause your due date to be wrong?”
What to know about fundal height
A fundal height measurement gives information about a developing fetus, such as its position and growth rate. A healthcare professional uses a tape measure to check the distance between the pubic bone and the top of the uterus.
The main purpose of measuring fundal height is to check whether the fetus is growing as expected. This article explores this measurement in more detail, including what it can tell someone about their pregnancy.
Measuring fundal height helps healthcare professionals screen for any irregularities in fetal growth.
The first measurement typically takes place after 24 weeks of gestation. This simple, affordable method can help healthcare professionals tell whether further investigation into fetal growth is necessary.
It can be a useful way of checking fetal growth in areas where access to medical equipment is difficult. Also, a doctor may gain a more accurate understanding by considering this measurement alongside an ultrasound scan.
A healthcare professional measures the distance from the pubic bone to the top of the uterus.
First, they may ask the person to empty their bladder, as having a full bladder may alter the measurement.
Next, they locate the upper border of the pubic symphysis, a joint between the left and right parts of the bottom section of the pubic bone. Then, they locate the uterine fundus, the uppermost, rounded part of the uterus.
They then use a tape measure to check the distance between these areas and record the measurement in centimeters (cm).
The first fundal measurement typically takes place after 24 weeks . The care team then takes more measurements as the pregnancy progresses and compares these with the average for a healthy pregnancy.
Fundal height generally corresponds with weeks of pregnancy, give or take 2 cm. For example, at 28 weeks, a person’s fundal height is usually within 2 cm of 28 cm.
Fundal height measurements can give information about the position and growth of a fetus.
Various factors can lead to inaccurate fundal height measurements. For example, if a pregnant person has obesity, their fundal height may be greater than that of the average for the gestation week. This can mean that the measurement is a less accurate way of checking fetal growth.
On the whole, fundal height is an accurate tool. The American College of Obstetricians and Gynecologists , for example, recommends it alongside ultrasound scans.
Here are some frequently asked questions about fundal height.
What if fundal height is low?
There are several reasons for a low fundal height. It indicates that the fetus is small, considering its gestational age. This may be no cause for concern.
However, in other cases, it may suggest that there is intrauterine growth restriction. Without effective treatment, this can cause mortality for the fetus and the pregnant person.
Another possible cause of a low fundal height is oligohydramnios. This refers to having too little amniotic fluid around the fetus. Without treatment, this can cause complications.
What if fundal height is high?
This can show that the fetus is growing too fast, which can carry risks for the fetus and the pregnant person.
A high fundal height can also stem from polyhydramnios , which means having too much amniotic fluid. This is not directly dangerous, but it can cause complications that put the pregnancy at risk.
However, it is important to note that a high fundal height may simply indicate that a person has multiple pregnancies, such as twins or triplets.
What if fundal height is ‘behind schedule’?
This can indicate that the fetus naturally grows at a rate that is slower than average.
But it can also indicate that a complication is restricting fetal growth. A healthcare professional can then check for complications with an ultrasound scan.
A healthcare professional uses a tape measure to check the distance between the pelvic bone and the top of the uterus. This measurement, in cm, is the fundal height. It can give information about the growth of a fetus.
The measurement typically aligns with the number of weeks that the person has been pregnant, give or take 2 cm.
Having a low or high reading may be no cause for concern, or it may point to a pregnancy complication. To assess this, a doctor uses other tools, such as an ultrasound scan.
Last medically reviewed on May 3, 2022
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- Basso, N. A. S., et al. (2020). Symphysis-fundal height curve in pregnancies complicated by maternal hyperglycemia: Comparison with curves of nondiabetic pregnant women.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7481913/ - Lee, A. C. C., et al. (2020). Prediction of gestational age with symphysis-fundal height and estimated uterine volume in a pregnancy cohort in Sylhet, Bangladesh.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069288/ - Papageorghiou, A. T., et al. (2016). International standards for symphysis-fundal height based on serial measurements from the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: Prospective cohort study in eight countries.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5098415/ - Peter, J. R., et al. (2015). Symphysial fundal height (SFH) measurement in pregnancy for detecting abnormal fetal growth.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465049/ - Sharma, D., et al. (2016). Intrauterine growth restriction: Antenatal and postnatal aspects.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4946587/