Fundal Height Calculator

Fundal height, clinically called 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 to measure gestational age and 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 fundal height is the distance between your pubic bone and the top of your uterus.

One test your doctor could perform at your pregnancy visits is measuring your fundal height. They could also check on your baby's health by looking at your baby using an ultrasound, doing tests on your body, listening to your baby's heartbeat, observing how often your baby moves, and verifying your physical health.

Doctors use all these elements to provide the most precise knowledge about your baby's development state.

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 can 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 continues up the abdomen as the pregnancy progresses. By 26 weeks, the fundus is usually by the belly button. By 36 weeks, it 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. 

Though techniques vary, fundal height assessments typically start about 20 weeks of pregnancy. The uterus has now developed enough to be felt above the pubic bone, simplifying outside measurement. Until the 36th week, the fundal height is usually assessed during every prenatal appointment. After 36 weeks, the baby could go lower in readiness for birth, so fundal height becomes less consistent. 

After 20 weeks, regular fundal height measurements provide consistent monitoring that can offer a comforting indication of consistent development. Measurements for women with disorders like obesity or uterine fibroids may occasionally be less reliable. Thus, alternative monitoring techniques like ultrasonic waves may improve evaluation.

The uterus starts a process called involution following childbirth, progressively reducing back to pre-pregnancy size. Beginning practically immediately upon delivery, this procedure starts with the uterus either above or just below the abdominal button. It keeps getting smaller over the first few days at a rate of one centimetre daily.

By the end of the first week postpartum, the uterus usually rests between the belly button and pelvic bone; by the second week, it has dropped into the pelvis and become invisible. The uterus usually returns to a non-pregnant size within six weeks, weighing almost 1000 grams shortly after delivery and averaging roughly 60 grams. < The rate at which the uterus rebounds to its normal size can be affected by carrying multiples or too much amniotic fluid.

Consistently higher or smaller than expected by roughly four centimetres, fundal height measurements could indicate specific problems. Should the fundal height measurements fall short of predicted, this could point to intrauterine growth restriction (IUGR), in which case the baby might not grow sufficiently. Conversely, a higher fundal height could be linked to disorders such as gestational diabetes, in which case the baby might develop bigger than normal.

Usually, an ultrasound is advised if fundal height shows a notable disparity. This enables a more thorough evaluation of the baby's weight, size, and amniotic fluid levels, ensuring that both mother and child get suitable treatment throughout the pregnancy.

Although it is not a perfect diagnostic tool, fundal height measurement is useful for monitoring overall development patterns throughout pregnancy. The precision of the measurement can vary; an expected margin of error of roughly plus or minus three millimetres exists. Although it provides insightful analysis of the baby's development over time, it is less reliable than an ultrasonic scan for identifying certain issues since measurements depend on variables such as the mother's body type, baby position, and amniotic fluid levels.

Usually ranging from weeks 20 to 37, the fundal height measurement (in centimetres) corresponds with the week of pregnancy. For instance, a fundal height measurement of 24 cm is customary around 24 weeks. However, measurements within a range of two centimetres above or below the week of pregnancy are normally regarded as normal. This advice enables one to monitor the baby's development in an understandable and instructive manner.

Should your fundal height deviate from expected, your doctor must conduct more investigations to ascertain the underlying cause. These tests could call for an ultrasound to gain a closer view of your baby or labs to check your body's condition. An odd fundal height measurement could point to something amiss with your kid.

Once your doctor has determined why your fundal height measurement is incorrect, they can assist you in determining, if any, what actions should be taken to enable your baby to grow at a healthy rate going forward.

Many elements that alter the size and shape of the uterus during pregnancy can affect fundal height measurements. Since this measurement approximates foetal development, anything that changes uterine size will affect the accuracy of the fundal height evaluation. These are some typical elements that could lead to variances in fundal height:

1. Amniotic Fluid Levels: The fundal height might vary depending on either low or excess amniotic fluid (oligohydramnios) or polyhydramnios. While low fluid levels could produce a lower measurement, higher than usual fluid levels could cause a bigger measurement. These disorders can call for ongoing observation and additional research to determine their source and effects on prenatal development.

2. Uterine Fibroids or Cysts: By enlarging the uterus, fibroids or other growths might raise the fundal height measurement. Although fibroids are benign tumours, their size, and location can affect the uterine shape and possibly pregnancy.

3. Anatomical Anomalies: Some anatomical variances, including a tilted or retroverted uterus (when the uterus tilts backwards rather than forward), can change the apparent fundal height. Usually benign and widespread, these disorders may affect fundal height readings from normal levels.

4. Maternal Body Mass Index (BMI): Fundal height measures may be less accurate in those with more abdominal tissue, especially when their BMI rises. The additional tissue might cause the uterus to sit differently or cover its top, influencing the measurements and interpretation.

5. Multiple Pregnancy (Twins or More): Carrying multiples naturally increases uterine size, often resulting in a larger-than-average fundal height for a given gestational age. This is typically expected in twin or multiple pregnancies, but healthcare providers closely monitor these pregnancies for accurate growth assessments.

6. Foetal Growth Rate: Individual development patterns affect foetal growth rate, which might vary. While faster development could produce a greater measurement, slower development may produce a lesser fundal height. Intrauterine growth restriction (IUGR), slower or limited development, may call for further ultrasounds to ensure the baby is growing normally.

7. Foetal Positioning: The baby's location in the uterus may momentarily change the fundal height. For instance, the fundal height may vary depending on whether the infant is sleeping horizontally or in a transverse posture compared to if the infant is positioned vertically. Though they can affect measures, changes in foetal position are normal and usually do not point to a concern.

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

It is very important as it is the first sign of problems with the developing baby. When the fundal height is less than the gestational age by more than 3, there's a possibility that the baby is not the expected size 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 than your gestational age in the following conditions:

Fundal height is a simple yet powerful way to track your baby's growth and development. Regular measurements can catch potential issues early, ensuring both you and your baby stay healthy. If something seems off, further tests like ultrasounds can provide clarity and guide the next steps. Stay on top of your fundal height to ensure a smooth and healthy pregnancy journey.

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.