Fundal Height Calculator

Fundal height, which is clinically referred to as Symphysio-Fundal Height (SFH) is a measurement taken in pregnant women after crossing 24 weeks of pregnancy. It is the distance between a prominence on your pubic bone and the top of the palpable uterus. It can be used as a measure of gestational age and to estimate foetal growth. Gestational age is the measure of the age of the pregnancy, that is, how far along you are in your pregnancy. 

Sometimes, there can be a discrepancy in calculating the gestational age due to irregular dates of your last period. Sometimes, the foetus may have some developmental issues resulting in decreased growth, which can be picked up by an SFH measurement not corresponding to the known gestational age. This can direct your doctor to order further tests to look for any possible problems with the pregnancy.

The calculator can be used to calculate the following three parameters.

The uterus is the organ that houses the developing foetus. It is present inside the pelvis in a non-pregnant woman. During pregnancy, the uterus has the capability to expand with the growing foetus. Once the pregnancy crosses 24 weeks, a normal foetus is big enough that the uterus longitudinally protrudes into the abdominal cavity, and can now be felt by palpating the abdomen. 

Once this occurs, Symphysio-Fundal Height can be measured as follows.

Once your pregnancy reaches 24 weeks, the fundal height measured corresponds to the number of weeks of your pregnancy (gestational age), plus/minus 2. For example, if you are in your 29th week, the expected fundal height is 29 cm +/- 2 cm. 

The position of the fundus gradually changes and keeps going up the abdomen as the pregnancy progresses. By 26 weeks, the fundus is usually by the belly button. By 36 weeks, the fundus reaches the breast bone (so, the fundal height will be around 36 cm).

Following this, there will be a drop in the fundus and a decrease in the fundal height. As the baby gets close to being born, it slowly starts descending and occupying the lower areas of the pelvis. The part of the baby over the vagina will enter the pelvis as it makes its way out. This is called engagement, typically of the head, which can cause the fundal position to lower and a consequent decrease in the fundal height. 

Fundal height is one of the easiest, simplest, and completely non-invasive methods of monitoring the progress of pregnancy and the health of the developing foetus. It does not cost any extra money and can be performed easily. 

It is very important as mostly it is the first sign of picking up any problems with the developing baby. When the fundal height is less than the gestational age by more than 3, it means that there's a possibility that the baby is not the expected size it should be for its age. This can prompt your doctor to perform an ultrasound scan which offers a much more comprehensive look at the foetus and state of pregnancy. 

There is a margin for error, but this measurement has been an extremely useful tool in clinical practice. Typically, once you cross 24 weeks, your fundal height is measured at every visit. In addition, your doctor will look for the baby's heartbeat with a handheld Doppler probe. They will also palpate your uterus abdominally to look at its contour, check which direction the baby is lying in, and check for other abnormalities. 

Your Symphysio-Fundal Height can be less in comparison to your gestational age in the following conditions.

Symphysio-Fundal Height can also be more than your expected gestational age. This is seen in the following scenarios.

Disclaimer: The content on this page is generic and shared only for informational and explanatory purposes. Please consult a doctor before making any health-related decisions.