The fundal height measurement is a simple, non-invasive method used during pregnancy to estimate fetal growth and development. The “fundus” is the broad, curved, uppermost part of the uterus, farthest from the cervix. Palpation is the medical technique of using hands and fingers to feel the body’s surface and underlying organs. In this context, it describes feeling the abdomen to locate the top of the expanding uterus. The measurement is the distance, in centimeters, from the top of the pubic bone to this highest point of the uterus.
Reasons for Tracking Uterine Growth
Monitoring the size of the uterus is a standard part of prenatal care, serving as a screening tool for consistent fetal development. By tracking the fundal height over successive weeks, a healthcare provider establishes a growth curve for the pregnancy. This verifies that the fetus is growing at a predictable rate, typically starting around 20 weeks of gestation.
A measurement significantly smaller or larger than expected for the gestational age signals a need for further investigation. A measurement that is too small might suggest intrauterine growth restriction. Conversely, a measurement that is too large could indicate multiple gestations (such as twins) or an excessive volume of amniotic fluid, known as polyhydramnios.
The fundal height measurement is a quick way to identify potential issues that warrant a more accurate diagnostic tool like an ultrasound scan. It is one of several factors used to assess the overall health of the pregnancy. Consistent charting helps ensure that any deviation from the expected pattern is addressed promptly.
Step-by-Step Guide to Fundal Height Measurement
Before measurement, the bladder should be emptied, as a full bladder can artificially increase the fundal height. The individual should lie on their back in a comfortable, semi-reclined position, allowing the abdomen to be fully exposed. This positioning helps relax the abdominal muscles for accurate palpation.
The first step is to locate the symphysis pubis, the firm bone at the top of the pubic area, which serves as the fixed starting reference. Next, the fundus must be located by gently pressing the fingers across the upper abdomen to find the highest, firm curvature of the uterus. This palpation determines the top boundary of the uterine growth.
Once both points are identified, a flexible tape measure is used. The zero end of the tape is placed firmly at the top edge of the symphysis pubis. The tape is then stretched vertically, following the curve of the abdomen, straight up to the top edge of the fundus.
The final measurement is read in centimeters where the tape meets the fundus. Measure along the longitudinal axis of the uterus for consistency. This recorded number is the fundal height, providing the data for tracking uterine expansion.
Interpreting Results and When to Consult a Professional
After approximately 20 to 24 weeks of pregnancy, the measurement in centimeters should roughly correspond to the number of weeks of gestation. For example, at 27 weeks, 27 centimeters is expected. A variance of 2 to 3 centimeters in either direction is considered normal, and this correlation is most accurate between the 20th and 36th weeks.
If the fundal height is consistently outside this range by more than 3 centimeters, further evaluation may be needed. A measurement that is too small could suggest restricted growth or low fetal positioning. A significantly larger measurement may indicate an incorrect due date, a larger fetus, or a higher volume of amniotic fluid.
Fundal height is a screening tool, not a definitive diagnosis; factors like maternal body habitus or fetal position can affect the reading. If a measurement raises concern, a healthcare professional typically orders an ultrasound for a more accurate assessment. Consult a provider immediately if you notice an extreme deviation, sudden pain, or other concerning symptoms.